tag:blogger.com,1999:blog-48757721191878266632024-03-12T16:44:55.215-07:00Food ParadigmA blog on food and health topics concentrating on deconstructing papers - especially on nutritional epidemiology.Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-4875772119187826663.post-50084654294854108602011-06-13T13:21:00.000-07:002011-06-13T13:26:28.549-07:00Nutrient Intake and Substrate Oxidation part 2Nutrient Oxidation and Nutrient Balance Results in Hill et al. <a href="http://www.ajcn.org/content/54/1/10.abstract">"Nutrient balance in humans: effects of diet composition", AJCN, 1991, vol. 54, pp. 10-17.</a><br />
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<div style="text-align: justify;">The experiment provides convincing evidence that oxidation of substrates varies with intake. Fig. 2* can also be used to verify roughly (by printing out the graph, estimating the nutrient oxidation of each bar using the scale and adding them up) that the total nutrient oxidation does not differ significantly between diets and between diet and baseline.<br />
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<img alt="http://4.bp.blogspot.com/-aMCd5vzyPik/Te7APcq2DNI/AAAAAAAAAlY/vQ5SbMGpxJI/s1600/Hill+et+al+nutrient+oxidation+figure+2.jpg" src="http://4.bp.blogspot.com/-aMCd5vzyPik/Te7APcq2DNI/AAAAAAAAAlY/vQ5SbMGpxJI/s1600/Hill+et+al+nutrient+oxidation+figure+2.jpg" /><br />
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<div style="text-align: justify;"></div></div><div style="text-align: justify;">The nutrient balance calculated as 'intake - oxidation' uses the otherwise unreported caloric intake data and is shown in Fig. 3.</div><div style="text-align: justify;"><a href="http://2.bp.blogspot.com/-ZknyhKfDiFw/Te7AQNo1qSI/AAAAAAAAAlc/oQEaup0ZN3U/s1600/Hill+et+al+nutrient+balance+figure+3.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" height="237" src="http://2.bp.blogspot.com/-ZknyhKfDiFw/Te7AQNo1qSI/AAAAAAAAAlc/oQEaup0ZN3U/s320/Hill+et+al+nutrient+balance+figure+3.jpg" width="320" /></a> </div><div style="text-align: justify;">First of all it is interesting that the subjects were in positive carbohydrate balance at baseline - the mean value (although we are told that inter-subject variation was large) is about 144 cal/day** (and about 24 cal/day or less for fat balance). The authors of the paper describe the fat balance of the baseline diet as 'near-zero' - this is presumably because there is again considerable intersubject variation - indicated by the error bar extending out to about -167 cal/day. But where is the excess carbohydrate going? Well, it could be filling up glycogen stores, but equally, if the glycogen stores are full, it could be converted and stored as fat. Just because it appears in the 'carbohydrate' column, does not mean that it is not being converted to fat for storage. The fat column is fat intake minus fat oxidation, which does not preclude fat storage from another source - it was not possible to measure the exact amount of fat going into the subjects’ adipose.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In the case of the high fat diet, the authors comment that fat oxidation increases </div><blockquote><div style="text-align: justify;"><i>"such that by day 3 fat balance was maintained near zero and remained near zero through day 7 "</i></div></blockquote><div style="text-align: justify;">In fact fat balance appears to be negative on day 3 (unless an extensive error bar has been accidentally omitted in the positive direction) and even though it does appear to be slightly positive by a bit less than 24 cal/day (as for baseline) on day 7, the error bar still extends well into negative territory. Compare the characterization of the graph at <a href="http://donmatesz.blogspot.com/2011/06/fat-balance-versus-energy-balance.html">PW</a>: </div><blockquote><div style="text-align: justify;"><i>but by day seven, they were in positive fat balance (burning less fat than consumed)--hence, on day seven they were storing dietary fat in adipose. This happened despite the fact that they had increased fat oxidation. Decreasing dietary carbohydrate forced the body to burn more fat, but because they were consuming a high fat diet, they were consuming more fat than they could burn in a day, resulting in a positive fat balance....increasing adipose.</i></div></blockquote>So the mere fact of consuming a high fat diet causes you to automatically consume more fat than you can burn in a day???<br />
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<div style="text-align: justify;">Anyway the most interesting thing about these results is <i>not </i>that there is a negative fat balance on the HC diet and not on the HF diet. Even the authors point out that this is not an interesting finding:</div><blockquote><i>"It is important to note that total fat oxidation did not increase when subjects were given the high-carbohydrate diet. Rather, negative fat balance resulted because dietary intake of fat decreased dramatically while fat oxidation decreased only slightly ."</i></blockquote>No, the real increase in fat oxidation occurred in response to the HF diet (and to a lesser extent in the mixed diet which was only 35% carbohydrate).<br />
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<div style="text-align: justify;">What <i>is </i>of interest is that all diets had positive carbohydrate balance. Now in the case of the HC and mixed diets there also appears to be a caloric deficit (-36 to -12 cal/day over the two days of the HC diet and -48 to -60 cal/day over the two days of the mixed diet), so the positive carbohydrate balance just represents a shuffling of substrates. In the HC diet case it might represent a ‘carb loading’ response - maybe the body was taking the opportunity to top up glycogen stores in response to the higher carbohydrate intake. Some of the carbohydrate might have been used for non-oxidative purposes such as making glycoproteins, but equally some of it (the fructose at least) might have been converted to fat.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">On the other hand, in the HF diet (as well as baseline) case it appears that there was a positive caloric balance (+155 to +167 cal/day at baseline, +72 to +107 cal/day over the two measurement days of the HF diet). In this case, perhaps the excess carbohydrate was converted to fat – what else can have happened to it?</div><br />
<div style="text-align: justify;">The authors state that the experiment was conducted in conditions of 'near energy balance' and it appears that, within the error margins of their methods, they may be justified in making that claim. The negative and positive caloric differences are very small. However, information such as caloric intake – which could be compared with daily energy expenditure for days 3 and 7 - has not been shown. Also the results of the body composition weighings are not shown or even mentioned again. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The fixed intake across all diets was part of the experimental design as the focus was to be on varying the diet composition and seeing how the body responded, but the data suggests that this resulted in a slight overfeeding on HF and a slighter underfeeding on HC which is potentially a more interesting finding*** but here is the authors' comment on this:</div><blockquote><i>"The data do suggest, however, that high-carbohydrate diets may be more effective in body-weight management than are high-fat diets fed at the same level of total calories owing to the greater negative fat balance seen under high-carbohydrate-feeding conditions. "</i></blockquote>As Tom Naughton would say: Head. Bang. On. Desk.<br />
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*The figures have been copied from the<a href="http://donmatesz.blogspot.com/2011/06/fat-balance-versus-energy-balance.html"> post at Primal Wisdom</a>.<br />
**All values in the paper are given in kJ which are about 4 times bigger than the more familiar ‘calories’ (actually kcal), here they are converted to nutritional calories.<br />
*** In a way the authors are refreshing in sticking to conclusions about their original aims.Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-48836099193522673842011-06-13T11:53:00.000-07:002011-06-13T12:19:05.941-07:00Nutrient Intake and Substrate Oxidationor some comments on <a href="http://www.ajcn.org/content/54/1/10.abstract">Hill et al. "Nutrient balance in humans: effects of diet composition", AJCN, 1991, vol. 54, pp. 10-17.</a><br /><br /><div style="text-align: justify;">Recently the study above was analysed and presented (on <a href="http://donmatesz.blogspot.com/2011/06/fat-balance-versus-energy-balance.html">Primal Wisdom blog</a> q.v.) as support for arguments that:<br /></div><ol><li>the body does not manage 'energy balance', it manages substrate stores and<br /></li><li>high fat diets may not be good for weight loss because they may make it too easy to (paraphrasing the end of the blog post) consume more fat than your body burns daily, (so that) you will increase your body fat day by day.</li></ol><br /><div style="text-align: justify;">Now, point no. 1 is both complicated and simple. It is complicated in that it seems clear from much emerging evidence about hormones such as leptin and ghrelin and brain functions that the brain and the body does have extremely complicated mechanisms for controlling 'energy balance' (see <a href="http://wholehealthsource.blogspot.com/">Whole Health Source</a> for many articles and discussions on this topic). It may do this by either controlling input e.g. by modulating appetite or by controlling output e.g. by modulating metabolic rate, activity levels (inclination to be more or less active) or waste heat production. It is simple only in the fact that there are indeed three basic macronutrient categories which correspond roughly to 'strucutural' (i.e. protein), 'limited storage' (i.e. glycogen (carbohydrate) and 'unlimited storage' (i.e. adipose (fat)). It is within this very limited perspective that this particular paper explores the issue which amounts to peering at metabolism through a keyhole. This paper succeeds in showing that nutrient intake is an independent factor influencing substrate oxidation so that body/brain control of 'energy balance' has to work within the constraints of the hormonal responses to nutrient intake but it doesn't prove that it trumps all other influences.<br /><br /></div><div style="text-align: justify;">The second point of the blog article is that high fat diets may be an impediment to fat loss because if you eat high fat it is too easy to store any fat you accidentally overeat. I do not want to imply that the blog article is stating that high fat diets will inevitably cause weight gain or impede fat loss, but it comes very close to claiming this:<br /></div><blockquote></blockquote><span style="font-style: italic;"><blockquote>You might be able to achieve this on a low carbohydrate diet, and you might not. If eating a low carb diet allows you to eat less fat than you burn daily, you will lose fat, and if it doesn’t you will not. On the other hand, regardless of theoretical "energy" intake, if eating a low carbohydrate diet results in your consuming more fat than your body burns daily, you will increase your body fat day by day.</blockquote></span><div style="text-align: justify;">So let's look at the study, what it set out to do, how it did it and what the results were.<br /></div><br /><div style="text-align: justify;">There were two main aims of the study stated by the authors: to examine the effect of diet [macronutrient] composition on [overall] energy expenditure and on nutrient balance. Their conclusions were that diet composition did not affect total daily energy expenditure but did affect nutrient balance as the substrate oxidation shifted to match the diet composition.<br /></div><br /><div style="text-align: justify;">The subjects in the study were overweight to moderately obese: BMIs ranged from 26 to 34 and body fat% in the 30% range in the males and high 30% to high 40% in the females. The study methods on the whole are precise and careful. For example, body composition was measured using underwater weighing and the functioning and calibration of the indirect room calorimeter are described in detail. Activity or movement in the room calorimeter was estimated using a radar monitoring system and estimates of sleeping metabolic rate (SMR), as distinct from resting metabolic rate (RMR) were also made. Body composition, RMR and 24 hour energy expenditure were measured repeatedly throughout the experiment:<br /><blockquote style="font-style: italic;">"1-2 d before beginning each experimental feeding period."</blockquote></div><blockquote style="font-style: italic;">"Body composition was determined at the beginning and end of each experimental feeding week..." </blockquote>but this data is not reported.<br /><div style="text-align: justify;">The paper is also less than clear when it describes caloric intake. From the abstract:<br /></div><span style="font-style: italic;"></span><blockquote><span style="font-style: italic;">"For each subject, total caloric intake was identical on all diets and was intended to provide the subject's maintenance energy requirements."</span></blockquote><div style="text-align: justify;"><div style="text-align: justify;">To do this the amount of food given to the subjects was estimated as 1.5 x RMR where the RMR (which includes TEF (thermic effect of food)) was calculated based on a 24 hour session in the room calorimeter. It was noted by the authors that the resulting intake was </div><blockquote style="font-style: italic;">"for a level of activity typically seen during 24 h in the room calorimeter"</blockquote> and pointed out that this <blockquote><span style="font-style: italic;">"might have resulted in negative energy balance on other days when activity outside the calorimeter may have been greater."</span></blockquote><br /></div><div style="text-align: justify;">It is stated that all food was consumed on site at the research centre and food that was not eaten was weighed. This information is used later to calculate the difference between intake and oxidation for the different substrates. However caloric intake on any of the diets is not reported.<br /><br /></div><div style="text-align: justify;">The results for daily energy expenditure (DEE) support the assertion that caloric intake was identical for each diet for each subject as the authors state that total daily energy expenditure did not change according to diet. It has to be assumed then that any changes shown in Table 3 are non-significant (although this isn't explicitly stated), as there is some variation within each subject from measurement to measurement (it would be surprising if there wasn't). Mean results for RMR, SMR and energy expenditure due to activity as shown in Table 4 are more convincing as it is easy to see that the standard error on the means puts all the results for baseline and the different diet periods within reach of each other.<br /><br /></div><div style="text-align: justify;">There are two exceptions:<br /><ol><li>the authors note that the values for the mixed diet period are higher and that this is because two subjects, who happened to have the lowest activity levels, were excluded from this part of the experiment</li><li>the mean energy expenditures due to activity during the high carb diet were noticeably (although again presumably not significantly) lower than for the high fat diet.</li></ol></div><div style="text-align: justify;">However, again it seems odd that given that the information for caloric intake and energy expenditure was available, that overall caloric balance was not reported.<br /><br />In the follow-on post, the nutrient balance figures will be discussed.<br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-36762903309844319832009-08-25T14:39:00.000-07:002009-08-27T12:38:22.802-07:00Latest low carb diets cause atherosclerosis story<div style="text-align: justify;"><a href="http://news.bbc.co.uk/2/hi/health/8218780.stm">This story</a> will gladden the hearts (pun not intended actually) of all establishment thinkers everywhere and strike fear into those on a low-carb diet. This is not a joke, according to an interview with the study authors, this study was carried out partly to convince one of them to get off his low-carb diet.<br /></div><br /><div style="text-align: justify;">Three groups of apoE-/- mice (have genetic defects which mean their lipoproteins don't work properly, see Peter's quick overview <a href="http://high-fat-nutrition.blogspot.com/2009/08/low-carbohydrate-high-protein-and-apoe.html">here</a> or my previous post on another study <a href="http://talkingfood.blogspot.com/2009/05/atherogenesis-in-mice.html">here</a>) were fed either standard chow (extremely high carb - 65% of energy and low fat) a 'Western diet' (halfway down the aforementioned <a href="http://talkingfood.blogspot.com/2009/05/atherogenesis-in-mice.html">mouse-related blog post</a>) and a <span style="font-style: italic;">specially constituted</span> low-carb diet. Fortunately, the low-carb diet details are found in the supplementary matter provided with the paper and show that it was 12% carb, 43% fat and 45% protein. It was extremely low in sucrose and corn starch and the fat source was milk fat. This means that prima facie, neither sugar nor excessive PUFA can be blamed for the excess (slightly more than twice as much) aortic atherosclerosis in the low-carb vs the western diet mice.<br /><br />But wait, it's not just a low-carb diet, it's an especially high-protein diet and to be fair to the researchers that seems to have been their intention. In the first place to change only one variable - so they held the fat content steady with respect to the western diet and cut the carbs. To keep the diet iso-caloric (to avoid the confounding effect of energy intake differences) they had to increase another macronutrient, so they chose protein. A second reason for this might be that ,in general, low-carb diets for humans (which should really be high fat diets (43% No?! <span style="font-style: italic;">really</span> high-fat - try 68%)) are often camoflauged as high-protein diets to smoothe the sensibilities of the fat-phobes. And to be fair again, the authors do pass comment that the results point out effects of <span style="font-style: italic;">macronutrients other than fat</span>.<br /><br />So, first reactions:<br /><ul><li>the diet is really, really high in protein - 45% - this could be directly bad for the mice, for these particular mice or for any mice. For humans, it's well-known that there is a physiological limit to protein intake - 30-40% is the often quoted figure. This quote is from <a href="http://www.thepaleodiet.com/faqs/#General">Loren Cordain's paleo diet faq</a>.<br /></li></ul><span style="font-style: italic;"><blockquote>It is physiologically impossible to gain weight when lean protein is the only food consumed because of the body's limited ability to break down protein and excrete the by-product of protein metabolism (urea). This limit is called the physiological protein ceiling and varies between 30-40% of the normal caloric intake in most people, assuming they are consuming their usual (eucaloric) energy intake. Continued consumption of lean protein at or above the physiological protein ceiling without added fat or carbohydrate will elicit symptoms of so-called "rabbit starvation," a malady eliciting lethargy, diarrhea, weight loss, electrolyte imbalances, and eventual death. Hence, all people will lose body weight if limited to consumption of lean protein.</blockquote></span><blockquote></blockquote><br /><ul><li>Most studies of the danger of high protein intake focus on renal consequences and one study on rats found no ill consequences of a 50% protein intake (however, the study was really short-term). It's extremely difficult to establish what other issues there might be with a very high protein intake.<br /></li></ul><br /><ul><li>The protein given to the mice was casein. While not wishing to add to the hysteria over milk and heart disease (and being a cheese lover), it has to be pointed out that milk protein has some form (admittedly in the shape of weak epidemiological evidence) in the causes of CHD stakes. There is an extensive discussion in the comments at Whole Health Source <a href="http://wholehealthsource.blogspot.com/2009/08/ischemic-heart-attacks-disease-of.html">here</a>. And despite all the folklore surrounding mice and cheese, mice aren't really cheese-eaters.</li></ul><br /><li>If the mice were being given protein well in excess of their natural requirements, then the excess would have to be dealt with. Excess nitrogen is excreted (hence the kidney concerns) and the rest is converted to glucose (gluconeogenesis) and either burnt for energy or stored as fat. Hence, a high protein diet - with much too much protein - becomes the equivalent of a moderate carb (self-made glucose into the bloodstream/liver) and moderate fat diet.<br /></li><br />To see this consider the following example: a 2000 calorie western diet with 42% carb/43% fat/15% protein has 210g carbs, 95g fats and 33g protein whereas a 2000 calorie 'low-carb' diet with 12%C/43%F/45%P has 60 g carbs, 95g fat and 100g protein. Let's say 15% protein or 33g matches the body's protein needs, that means in the second diet there are 67g extra. While this <span style="font-style: italic;">doesn't</span> mean that 67g of carbs will be generated, it does mean that the diet does have greater parity in the quantity of carbs and fats presenting for energy provision, which isn't a good thing physiologically.<br /><br />Update: this probably isn't the reason the mice on the 'low-carb' diet did worse than the western diet mice. Apart from the simple fact that apoE -/- mice are doomed by their genetic oddity, there seems to be an extra issue with the high protein -specifically the casein which leads to kidney damage and a specific effect on those cells which can regenerate blood vessel damage - see Peter's updates <a href="http://high-fat-nutrition.blogspot.com/2009/08/low-carbohydrate-high-protein-and-apoe.html">here</a>.<br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-77246304152359343902009-06-07T09:45:00.000-07:002009-06-08T04:10:55.994-07:00The American Paradox<div style="text-align: justify;">Stephan over at <a href="http://wholehealthsource.blogspot.com/">Whole Health Source</a> is doing a series on Omega-6 and its possible role in the heart disease epidemic of the 20th century. This inspired me to put a series of sample daily menus into Fitday to see just how much omega-6 average people with different types of diet might actually be eating.<br /></div><br /><div style="text-align: justify;">First up is an individual who is not health-conscious. An example might be a young (male) student. He starts the day with a bowl of sweet cereal (cocoa puffs) with milk and sugar. Then lunch is a chicken roll (actually I chose a Subway Sub- but only 6"). For snacks during the day he eats a bag of potato chips and a Snickers bar. In the evening, he shares a pizza with mates, followed by some ice-cream. He drinks soft drinks as well as coffee and all the milk (and ice-cream) is full-fat.<br /><br />Not surprisingly this diet is high calorie (3205 kcal) and high-fat (although not as high-fat as my diet!): 40% fat (144g) by energy, 48% (394g) carbohydrate (which is within the average minimum daily recommendation (45-60%) of the 2005 dietary guidelines) and only 13% protein (106g). What is surprising is that, according to Fitday, such a menu contributes only 13% of calories as saturated fat - putting it close to the recommendation (less than 10%); 10% as monounsaturated fat and a whopping 13% fat as polyunsaturated fat. Most of that polyunsaturated fat will likely by omega-6 fatty acids as its source is the vegetable oils which are ubiquitous in processed foods. This indiviudal's body cell membranes will be saturated with omega-6 fats as in Stephan's graph <a href="http://wholehealthsource.blogspot.com/2009/05/eicosanoids-and-ischemic-heart-diseas.html">here</a>.<br /><br />If you eat processed foods, the only way to get your omega-6 polyunsaturates down would seem to be by eating a very low fat diet. Here is my 'extremely health-conscious low-fat eater's' diet. This lady starts the day with oatmeal porridge made with water, followed by multigrain toast with a smear of honey. She always puts skim milk in her tea and coffee and doesn't take sugar. A home-made chicken (breast meat, no skin!) and salad sandwich is followed by an apple. Although she succumbs to an oatmeal cookie with her cup of tea, dinner is a healthy chicken and vegetable affair on wholewheat macaroni, followed by a banana and light ice-cream. Trouble is she's hungry later, so it's a non-fat yoghurt and a small bowl of muesli (skim milk of course) just before bed.<br /><br />Actually, I had to add those snacks in, not only because our subject might be hungry due to the lack of fat and overload of carbohydrates but just to get the calories up above starvation levels to a respectable 1842 kcal. This diet is 22% fat (46g), 61% carbohydrate (294g) and 17% protein (80g). It has only 5% of total calories as saturated fat, 8% as monounsaturated fat and 6% as polyunsaturated fat. So even with a diet meeting the 2005 dietary guideline recommendation for carbohydrate and fat intake (20-35%), the intake of polyunsaturated fat is above the level which may cause problems if it is predominantly omega-6 as explained <a href="http://wholehealthsource.blogspot.com/2009/05/for-those-not-scientifically-inclined.html">here</a>.<br /><br />What about someone in between those two extremes? Here is someone who is trying to eat 'healthily' but not always succeeding. This person starts the day with 'heart-healthy' Cheerios with 2% fat milk and some toast with jam, but is hungry by mid-morning so succumbs to a muffin with a Latte coffee. H/she also eats a chicken and salad sandwich for lunch - but not necessarily home-made - and an apple. Hungry in the afternoon, a diet brownie is eaten. Dinner is chicken in a cheese sauce with macaroni (white not wholewheat) and a green and tomato salad with a commercial dressing, followed by some tinned fruit and light ice-cream.<br /><br />This diet is 2176 kcal and still within dietary guidelines: 30% fat (75g) and 55% carbohydrate (302g) and about the same amount of protein (80g) or 15% by energy as in the low-fat diet. Once again, polyunsaturated fat is high - 10% , equal to the proportion of monounsaturated fat, and thanks to all the innovative processed foods eaten, saturated fat consumption is well within the dietary recommendation target at only 8%.<br /><br />So this is the American paradox. Thanks to the processed foods now available, saturated fat consumption has been reduced towards target. Even the least health conscious can now eat pizzas, snack foods and chocolate bars and be approaching the holy grail of 10% of calories! The public have long been doing their bit to get their carbohydrate consumption up to above 50% - that part is easy since carbohydrates are really quite addictive. So why are there still health problems, why is there still overweight and obesity? That is the American paradox.<br /><br /><br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-9138268025866514292009-05-29T14:56:00.000-07:002009-05-31T01:43:37.679-07:00The 1 Really Important Thing We Didn't Tell You About Losing Weight<div style="text-align: justify;">The most interesting part of <span style="font-style: italic;">10 Things You Need to Know about Losing Weight </span>was the segment which focussed on an overweight actor. This lady revealed that she had always been large and that she felt that she had a 'slow metabolic rate'. She also stated that she had given up worrying up about her weight or trying to diet and just concentrated on eating a healthy diet and being active. Clearly, neither was helping her to lose weight.<br /></div><br /><div style="text-align: justify;">This idea that you are overweight because you have a body that burns food off more slowly is, of course, a common belief, but it isn't the case. Indeed, as Gary Taubes explains in his book G<span style="font-style: italic;">ood Calories, Bad Calories</span> [Alfred A. Knopf, NY, 2007] in the chapter Paradoxes (p. 278):<br /><br /><blockquote><span style="font-style: italic;">The most obvious difficulty with the notion that a retarded metabolism ... is that it never had any evidence to support it. ... Magnus-Levy had reported that the metabolism of fat patients seemed to run as fast if not faster than anyone else's. .... The obese tend to expend more energy than lean people of comparable height, sex, and bone structure, which means their metabolism is typically burning off more calories rather than less. When people grow fat, their lean body mass also increases. They put on muscle and connective tissue and fat, and these will increase total metabolism...</span><br /></blockquote><br />For example, from <a href="http://www.fitday.com/">Fitday</a>, I, at 5'4" and 8 stone 3lbs, with a sedentary type of job require 2050 calories per day, whereas if I was 12 stone, I would need 2432 calories. As predicted, the metabolic rate for the subject of this segment came up perfectly normal.<br /></div><br /><div style="text-align: justify;">Next came an investigation into how much she was eating. Looking at the lady in question, I guesstimated 3000 calories per day for her. She thought she was eating 1900 calories or less. As most people really have no idea about calories and portion sizes, I don't find this surprising and I don't think it's a deliberate or even an unwitting self-deception. It's just understandable, because humans didn't evolve doing complicated calorie counts before putting food into their mouths.<br /></div><br /><div style="text-align: justify;">The test involved a 9-day diet record. Some of this was a video food diary plus a written food diary. The food that we saw looked perfectly reasonable: chicken and vegetables (though, my goodness - a whole head of broccoli?), (a very large) fruit salad, something dipped into a cup of coffee or tea. The guinea pig also drank doubly-labelled water so that the team could monitor her caloric intake. The result given to us was that she had underreported her food intake by 43% and that her actual intake was 3000 calories per day (score one me!)<br /></div><br /><div style="text-align: justify;">Two things need commenting on here. Firstly, the underreporting. So what? It is fiendishly difficult to estimate portion sizes. I should know, I do it quite a lot to use Fitday. I try to be quite accurate, occasionally weighing or measuring to try and learn to 'eyeball' - say 30g of cheese or 1 oz of ham. On the other hand, there is a temptation to cheat. In my case, if I see the carbs going too high, there is a definite urge to downsize my estimates, even if this is silly because I'm only denying reality.<br /></div><br /><div style="text-align: justify;">Secondly, what we <span style="font-style: italic;">weren't</span> told. We weren't told what her energy expenditure was. We were told that the doubly-labelled water technique told the team that her caloric intake was 43% higher than her food diary records showed. The implied conclusion was that she was overeating - here we go, she thinks she's eating 2000 calories a day and she's actually eating 3000 calories a day and so she's fat. Whereas in fact that's probably not the case. She would probably be in energy balance - most people are, even fat people - they plateau at a certain weight, they don't all keep on getting fatter and fatter and fatter....<br /></div><br /><div style="text-align: justify;">Now I thought this at the time, but I didn't know how right I was because then, to write this post I looked up the doubly-labelled water technique to see how it worked and found <a href="http://en.wikipedia.org/wiki/Doubly-labeled_water"> this </a>:<br /></div><blockquote style="font-style: italic;">the term doubly-labeled water test refers to a particular type of test of metabolic rate, in which average metabolic rate of an organism is measured over a period of time.</blockquote>and:<br /><blockquote style="font-style: italic;">Energy expenditure measurements are easier to perform since the development and application of the doubly-labelled water technique.*</blockquote><div style="text-align: justify;">In other words, to work out that she was eating more calories than she said, they proved that she was using that many calories because the test itself measures energy expenditure not actual energy intake! But they didn't tell us that and they didn't draw the obvious conclusion that she was in energy balance! Certainly, if she ate less than 3000 calories a day she could draw on the stored fat and not starve. But, as she had pointed out herself at the start of the segment, she was not trying to diet and just trying to 'eat healthily'. Possibly to a dietician or nutritionist 'eating healthily' for an overweight person, by definition ought to mean dieting. However, the point is that just eating normally, she was not overeating, s<span style="font-style: italic;">he was just eating as much as she needed to maintain her body</span> - including all the extra fat - without discomfort or hunger.<br /></div><br /><div style="text-align: justify;">Clearly, if she could only mobilise that fat and burn it up, she could eat less, so what is stopping that? The reason the fat mass isn't simply used as fuel as soon as we restrict calories is to do with the interplay of hormones in the body. In the simplest terms, if you have too much circulating insulin, then it promotes storage of fat in fat tissue and glucose burning in muscle. It does this because its job is to get excess glucose out of your blood because high blood sugar is damaging. Only if your insulin level is low, can your fat tissue release fat into the bloodstream and your muscles burn fatty acids.<br /><br />The <span style="font-style: italic;">carbohydrate hypothesis of obesity</span> basically says that carbohydrate intake promotes insulin release which promotes fat storage and the conversion of excess glucose (all starch breaks down into glucose) into fat for storage. So a person who eats a 'healthy diet' that would be 50-60% 'healthy' carbohydrates - 6-11 servings a day of cereals anyone? plus lots of fruit but is quite sensitive to this effect of insulin would convert all the excess to fat and store it. If they are unlucky their insulin stays relatively high <span style="font-style: italic;">preventing their body accessing this stored fat.</span> Now they are 'growing' (but outwards) and as long as enough carbohydrates are consumed to keep insulin 'too high' for fat burning, their appetite tells them they need to eat more and so on it goes.<br /></div><br />And that is why all nutritionists and dieticians and doctors should read Gary Taubes' book G<span style="font-style: italic;">ood Calories, Bad Calories</span> - published as <span style="font-style: italic;">The Diet Delusion</span> in many countries.<br /><br />*from Invited Commentary, Energy requirements assessed using the doubly-labelled water method, Klaas R. Westerterp, British Journal of Nutrition (1998), 80, 217–218. Available <a href="http://www.blogger.com/journals.cambridge.org/production/action/cjoGetFulltext?fulltextid=878900">here</a>.Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-79223918240079320422009-05-28T01:55:00.000-07:002009-05-29T05:51:11.354-07:00Review of 10 Things You Need to Know About Losing WeightI managed to watch <span style="font-style: italic;">10 Things You Need to Know About Losing Weight</span> (BBC 1, 9pm) last night without throwing anything at the screen - <a href="http://www.bbc.co.uk/programmes/b00ksh7c">click here</a> for a link to the program (may be available in the UK only) or <a href="http://news.bbc.co.uk/2/hi/uk_news/magazine/8068733.stm">here</a> for a related BBC Magazine article - but this may just have been because my hands were occupied taking notes so that I could blog about it.<br /><br />Here are the 10 things:<br /><br /><ol><li>Not sure what they called this, seemed to be a variation on: <span style="font-style: italic;">Don't go shopping when you're hungry</span>. The presenter had his brain MRI scanned, firstly on a full stomach, on a second occasion on an empty stomach, and while being shown pictures of food. His brain 'lit up' more in response to 'high calorie' food (chocolate eclairs) than 'low calorie' food (cucumber slices) when he was hungry; whereas when he wasn't hungry the response was the same.</li><br /><span style="font-style: italic;">Use of an expensive machine to discover the bleeding obvious: when you are hungry, you are more interested in food and, more than that, more interested in food that your brain knows (from prior experience) is more likely to provide you with calories. Actually, I suppose this kind of research is necessary - we should investigate 'what everybody knows' - and try and disprove it - that is the scientific method. It also raises another interesting point - which wasn't mentioned in the program (although to be fair it isn't strictly relevant). Why doesn't the hungry brain respond to pictures of fruit and vegetables? Perhaps it's because humans didn't evolve chewing their way through bucketloads of plant matter for hours?</span><br /><br /><li>Use plate size to trick the brain about portion size, i.e. use a smaller plate - less food will look like more. </li><br /><span style="font-style: italic;">Personally, I think this works, I've used it with children the other way round - i.e. put the food on a larger plate and it looks like less so they eat it up. However, if you don't eat 'enough', you may end up hungry later on and snack!</span><br /><br /><li>Count calories - save a few here and a few there e.g. have black coffee instead of cappuccino, and it will add up to fewer calories over the day/month/year, leading to you magically losing weight. </li><br /><span style="font-style: italic;">Or maybe you'll just be hungrier? Has there ever been a controlled trial of this idea to see if it actually works?</span><br /><br /><li>Fat people eat more than they think they do. </li><br /><span style="font-style: italic;"> Actually this was the most interesting point and worth a separate post of its own.</span><br /><br /><li>Eat protein because it leads to greater satiety.</li><br /><span style="font-style: italic;">This was demonstrated with a small-scale experiment during the programme. It has been shown by <a href="http://www.medicalnewstoday.com/articles/120310.php">studies</a>.</span><br /><br /><li>Liquid food (as opposed to drinks with food) fill you up for longer. This was also demonstrated with an actual experiment. </li><br /><span style="font-style: italic;">This point is different from the preceding one: the mechanism here is one of the physical constraints on digestion, whereas the fullness from protein comes from the release of a hormone (PPY) which interacts with other appetite regulating hormones (leptin, ghrelin). If you use soup to 'trick' your body into eating fewer calories than usual, you will likely eat more at the next meal, once the soup has been digested.</span><br /><br /><li>Choice causes overeating. </li><br /><span style="font-style: italic;">I thought the 'experiment' conducted to show this was quite poor. Two bowls of equal quantities of sweets were left out in an office canteen with a sign </span>Free Sweets<span style="font-style: italic;">: one bowl was obviously smarties, the other bowl held purple smarties only. The smarties all disappeared, the purple ones didn't. A better comparison would have been smarties vs. chocolate buttons (they're all the same). The purple smarties looked vaguely medicinal - how do we know that didn't put people off?</span><br /><br /><li>Calcium in dairy binds fat which you then excrete: over a month this can save you calories. </li><br /><span style="font-style: italic;">In fact, it saved the guinea pig in this experiment slightly more than 5g of fat per day or about 160g per month. (Sounds like a lot? - I eat that much fat every day! I'm not going to quibble about the loss of one day's consumption per month.) Interesting - bad for dairy's image as a source of calcium - how much of the dairy calcium is lost this way? Also, the presenter felt constrained to recommend 'low-fat' dairy for this strategy. Noteworthy that this was the only vestige of 'low-fat' dogma in the programme. On the other hand, if it truly is 'low-fat' dairy then there isn't much point is there - where's it gonna find the fat to bind?</span><br /><br /><li>Exercise - another interesting one. An experiment with the presenter on a treadmill showed that 90 minutes of fairly fast-paced walking (he was quite breathless after it) only burned about 19g of fat (171 calories).</li><br /><span style="font-style: italic;">Given that after 90 minutes of fast-paced walking you've probably built up a bit of an appetite, it isn't going to do much for weight loss is it? </span><br />However there is a punchline - an 'afterburn' effect where exercise boosts 'fat-burning' into the next day.<span style="font-style: italic;"> So this could work - but there is still that question: why will the greater amount of calorie burning going on, not prompt your body to ask you for more food?</span><br />Update: the effect of exercise to promote 'fat burning' is disputed by research - see article <a href="http://www.msnbc.msn.com/id/30826120/">here</a>.<br /><br /><li>Small amounts of extra movement during the day e.g. take the stairs instead of the lift, will boost your calorie burning. </li><br /><span style="font-style: italic;">Can't argue with this really, but the effect will be small (90 minutes on a treadmill = 171 calories) and once again it ignores the hormonal elephant in the room - which will be tackled in the next post about point 4.</span><br /></ol>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-77120747802883976022009-05-06T02:33:00.001-07:002009-05-06T11:46:56.594-07:00Atherogenesis in Mice<div style="text-align: justify;">Another day, another plug for the diet-heart hypothesis in <a href="http://news.bbc.co.uk/2/hi/health/default.stm">BBC Health</a>, even when the study being reported on <a href="http://news.bbc.co.uk/2/hi/health/8033205.stm"><span style="font-style: italic;">Scientists pinpoint fats danger</span></a> is really about molecular genetics(<a href="http://www.cell.com/cell-metabolism/abstract/S1550-4131%2809%2900063-1">Thorp et al.</a>,Reduced Apoptosis and Plaque Necrosis in Advanced Atherosclerotic Lesions of<i>Apoe</i> and <i>Ldlr</i> Mice Lacking CHOP,<i> Cell Metabolism </i>,Volume 9, Issue 5, 474-481, 6 May 2009, subscription required). The study showed that mice lacking a gene (CHOP) which helps to trigger cell death (apoptosis) had a 35% smaller area of plaques and 35% less apoptosis and 50% less necrosis (dead tissue) in plaques. To quote the researhers directly (as reported by the BBC): <p></p><blockquote style="font-style: italic;"> <p>Lead researcher Dr Ira Tabas said that previous research had suggested that this mechanism might be involvedin plaque rupture, but the magnitude of the effect uncovered in the latest study was a surprise.<br />He said: "The fact that we were able to isolate one gene encoding one protein with such a profound effect on plaque necrosis (death) was a big surprise."<br />Dr Tabas said the finding raised hopes of new drugs which could act on the key gene, or the associated mechanism, to cut the risk of dangerous plaques.<br />"Just about everybody in our society has atherosclerosis (thickening of the arteries) by the time we reach 20," he said.<br />"So the wave of the future in treating atherosclerosis will be in preventing harmless lesions in young people from becoming dangerous ones, or soothing dangerous plaques so they don't rupture as we age."</p></blockquote><p> </p>Never mind what effect such a treatment might have on necessary cell death (e.g. to deal with emerging cancers) in other parts of the body.<br /><br />Anyway, what does this have to do with diet and the heart? Well, again from the BBC article:<br /><blockquote style="font-style: italic;">Scientists have identified a genetic mechanism which appears to determine which fatty deposits in the arteries have the potential to kill us. Most of these plaques pose no risk to health, but a minority burst, forming blood clots, which can cause heart attacks or strokes. .....<br />Fatty deposits begin to form in the arteries of most people in their teens, but the vast majority are harmless.<br /></blockquote></div><div style="text-align: left;"><br /><div style="text-align: justify;">Here we see the perpetuation of the myth that fat just floats around in the bloodstream clogging up our arteries like it would a drainage pipe. Plaque formation is a much more complex process than that and its genesis is still not fully understood (see for example, extensive discussion <a href="http://www.cholesterol-and-health.com/Does-Cholesterol-Cause-Heart-Disease-Myth.html#debate">here</a> or <a href="http://www.spiked-online.com/Articles/0000000CAE78.htm">here</a>).<br /></div><br />But, ah you say, just read on ...<br /><blockquote style="font-style: italic;">The researchers bred mice prone to develop plaques, and fed them a high-fat diet for 10 weeks.<br /></blockquote></div><br />So what was this high-fat diet? It was the TD.88137 Western Diet (<a href="http://www.harlan.com/research_models_and_services/laboratory_animal_diets">Teklad Lab Animal Diets</a>, Harlan Laboratories, Madison, WI) which consists of:<table><tbody><tr><th><br /></th><th> g/kg</th></tr><tr><td>Casein</td><td>195.0</td></tr><tr><td>DL-Methionine</td><td>3.0</td></tr><br /><tr><td>Sucrose</td><td>341.46</td></tr><tr><td>Corn Starch</td><td>150.0</td></tr><br /><tr><td>Anhydrous Milkfat</td><td>210.0</td></tr><tr><td>Cholesterol</td><td>1.5</td></tr><tr><td>Cellulose</td><td>50.0</td></tr><tr><td>Mineral Mix, AIN-76 (170915)</td><td>35.0</td></tr><tr><td>Calcium Carbonate</td><td>4.0</td></tr><tr><td>Vitamin Mix, Teklad (40060)</td><td>10.0</td></tr><tr><td>Ethoxyquin, antioxidant</td><td>0.04</td></tr></tbody></table><br />(Data from this <a href="http://www.harlan.com/download.axd/51f8735f93f246f992ae40febe3f86f5.pdf?d=88137">pdf</a>.)<br /><div style="text-align: justify;">This diet is 17.3% protein, 48.5% carbohydrate and 21.2% fat <span style="font-style: italic;">by weight</span>, but 15.2% protein, 42.7% carbohydrate and 42.0% fat <span style="font-style: italic;">by energy</span>, thus approximating a typical Western-style diet which is high in fat and <span style="font-style: italic;">simultaneously high in carbohydrate</span>. Note that of the carbohydrates 70.4% by weight is sucrose! The mice are eating <span style="font-style: italic;">30% of calories as sucrose</span>. Now mice are not little people, but <a href="http://wholehealthsource.blogspot.com/2009/04/fructose-vs-glucose-showdown.html">what does that kind of intake do to people</a>?<br /></div><br />How does this compare to a mouse's real diet?<br /><div style="text-align: justify;">From <a href="http://books.google.ie/books?id=Vt6nUmz1yEQC">The Mouse in biomedical science</a> (<span class="addmd">James G. Fox, Stephen W. Barthold, Muriel T. Davisson, Christian E. Newcomer, 2nd ed., Academic Press, 2007) p. 28 we learn that it is still debated whether mice are <span style="font-style: italic;">granivores</span>, eating a wide range of cereals, oilseeds, and a variety of grass and plant seeds, or whether they live on a mix of plant and animal sources. However from the evidence presented in this book it appears that in many environments, mice eat small invertebrates for at least part of the year (i.e. when seeds are in short supply) or to supplement plant seed diets.<br /><br />In short, the typical composition of a diet of invertebrates is high in fat and protein e.g. from p.41 in </span><a href="http://books.google.ie/books?id=7qwm8-dHKuwC">Marsupial nutrition</a>, (Ian D. Hume, Cambridge University Press, 1999) it can range from 20-60% fat and 10-75% protein (by weight of dry matter) for typical things that a mouse might eat (insects and insect larvae). Cereals are typically 68-79% carbohydrate, around 10-15% protein and 2-7% fat, legumes are as much as 25% protein, typically 50-60% carbohydrate and only 1-2% fat whereas nuts (e.g. hazelnut) and oilseeds (e.g. sunflower) are typically about 15-25% protein, 50-60% fat and 15-20% carbohydrate (from various tables in <span style="font-style: italic;">On Food and Cooking</span>, H. McGee, 1st ed. Unwin Hyman, 1984).<br /><br />From this we can conclude that a typical wild mouse would for part of the year eat a diet that was mainly protein and fat and for another part of the year eat a diet that was high in carbohydrate - at least if it ate cereals, but not so much if it ate other types of seeds - but low in fat. It would not however be eating a lot of sucrose. The carbohydrate in grains and seeds is starch which is a polymer of glucose and does not contain fructose. As further support of this analysis <a href="http://high-fat-nutrition.blogspot.com/2008/09/physiological-insulin-resistance-wild.html">here</a> Peter of Hyperlipid considered data on what wild-type mice eat when given free choice: about 12% protein, 6% carbohydrate and 82% fat (all as proportions of energy).<br /><br />A final note about the mice. The mice used in the experiment were either <span style="font-style: italic;">apoe</span> or <span style="font-style: italic;">ldlr</span> mice. <a href="http://www.taconic.com/wmspage.cfm?parm1=901">Apoe mice</a> lack a particular lipoprotein (apolipoprotein E) which is important in both the HDL and vLDL cholesterol transporters, in particular:<br /><blockquote></blockquote></div><blockquote><div style="text-align: justify;"><span style="font-style: italic;">ApoE mediates high affinity binding of chylomicrons and vLDL particles to the LDL receptor, allowing for specific uptake of these particles by the liver, preventing the accumulation of cholesterol rich particles in the plasma<br />.....<br /></span><span style="font-style: italic;"> Mice develop normally, but exhibit five times normal serum plasma cholesterol and spontaneous atherosclerotic lesions</span><br /></div></blockquote><div style="text-align: justify;"><a href="http://jaxmice.jax.org/strain/002207.html">Ldlr mice</a> lack a proper LDL receptor and essentially mimic (familial) hypercholesterolaemia with a very high circulating LDL level and an increased propensity to develop atherosclerotic lesions <a href="http://jaxmice.jax.org/strain/002207.html">amongst other things</a>.<br /></div><br />Does <span style="font-style: italic;">this</span> not indicate that fat is the root cause? Well not necessarily.<br /><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><a href="http://en.wikipedia.org/wiki/Very_low_density_lipoprotein">vLDL</a> is made in the liver to transport triglycerides (made from excess carbohydrates intake) to the tissues for use and storage. At this stage, it does not contain <a href="http://en.wikipedia.org/wiki/Apolipoprotein_E">apoE</a>: it has to pick that up from HDL on the way. ApoE contributes to its recognition and re-uptake by the liver after it has performed its delivery task or it loses its apoE and becomes an LDL particle and is taken up by body cells with an LDL receptor. So, this process will become disrupted in an apoe mouse which does not have a proper apoE protein. No wonder it ends up with excess blood cholesterol (which really means excess circulating lipoproteins). Similarly as ldlr mice lack the LDL receptor, they cannot remove the LDLs left at the end of the described process. On the other hand, after digestion, fat is absorbed either directly into the bloodstream - if the molecule is small - which gets it to the liver (where it may contribute to triglyceride production) or, for larger molecules, as <a href="http://en.wikipedia.org/wiki/Chylomicron">chylomicrons</a> which go via the lymphatic system into the bloodstream and from there directly to fat tissue for storage or to the liver to be used to provide fuel.<br />So which is more likely to contribute to the problem - the 21.2% of food (by weight) that comes as fat (most of which doesn't go straight to the liver anyway) or the 48.5% of food (by weight) that comes as carbohydrate - three-quarters of which is sucrose and half of that is fructose (i.e. 17% by weight of the total food intake) which goes straight to the liver and <a href="http://entropyproduction.blogspot.com/2009_04_01_archive.html">comes out as triglycerides</a>.<br /><br /><br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-80757293205196194902009-04-28T05:41:00.000-07:002009-04-28T06:30:13.802-07:00Mediterranean Diet Score - What else does the model tell us?<div style="text-align: justify;">A further analysis of the expected (from the model) vs the observed numbers within each diet score category and eating particular amounts of each food group throw up more interesting observations. This doesn't mean that we are claiming that people should behave like the model and that we expected that their food choices would not be internally correlated in some way. In fact, we expected that they would be (so do these researchers which is why they are trying to describe a dietary pattern); this data gives us information on what these correlations are.<br /><br />We have already noted that <a href="http://talkingfood.blogspot.com/2009/04/data-patterns-in-mediterranean-diet.html">meat & poultry intake is actually largely independent of the diet score</a>. So, when researchers claim that a Mediterranean diet is <span style="font-style: italic;">low in meat</span>, we will know that that is not borne out by this data.<br /><br />Comparison of expected vs actual numbers in the low score (0-3) group shows that there are more people getting a low score because they score 0 for vegetables, fruit & nuts, legumes or fish consumption (i.e. they don't eat 'enough' of these). Conversely, in the high scoring group (6-9) there are more people than expected scoring a 1 in these same categories. There are also more people than expected scoring a 0 for meat & poultry, dairy and cereals in the high scoring group, i.e. they get a high score while still eating 'bad' amounts of these food groups. The suggestion here then is that the diet score is mainly a reflection of vegetable, fruit & nut, legume and fish consumption and is much less related to dairy and cereal consumption as well as being independent of meat consumption.<br /><br />What about the predicted correlation between meat & poultry, dairy and the monounsaturated/saturated fat ratio? Whether this has any impact is very hard to determine. The main reason for this is that the postulated effect is obscured by the data presentation. To see why consider this thought experiment:<br /><br />Let's assume our subject has a score of 6 so far and we have meat & poultry, dairy and the fat ratio still to determine. If <span style="font-style: italic;">either</span> meat & poultry <span style="font-style: italic;">or</span> dairy score 0 (i.e. greater than median consumption), this increases the chance that the fat ratio will also be scored 0, giving a final score of 7; if <span style="font-style: italic;">both</span> meat & poultry <span style="font-style: italic;">and</span> dairy score 0, then there is an even greater chance of fat ratio being 0, giving a final score of 6. But, we can't see the difference (i.e. that there are proportionally more scores of 6 and 7 and fewer of 8 than expected) because all scores 6-9 are lumped together. The same argument works in the other direction, making the scores 2 and 3 potentially more frequent than scores of 1, but again this effect is obscured when the low score includes 0-3. Perhaps this is why?<br /><br /><br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-28874435494645838102009-04-25T13:37:00.000-07:002009-04-28T05:41:23.723-07:00Data Patterns in the Mediterranean Diet ScoreThe original construction of the edifice known as the Mediterranean Diet began with a paper which used a scoring system to handle the mass of data that results when you give thousands of people food frequency questionnaires. The data manipulation is roughly like this: People say how often and how much they eat of typical dishes and foodstuffs; these quantities and frequencies are converted to daily food group consumption for which a score is given. RESULT massive amounts of data reduced to one number.<br /><br /><div style="text-align: justify;">Let's recall the <a href="http://talkingfood.blogspot.com/2008_10_01_archive.html">basics</a>: the food groups were: vegetables, fruits & nuts, legumes, meat & poultry, fish, dairy products, cereals, monounsaturated to saturated fat intake ratio and alcohol intake. The <span style="font-style: italic;">bad</span> score was 0 for eating <span style="font-style: italic;">more</span> of the bad groups (meat & poultry, dairy, low mono to saturated fat ratio and alcohol) and <span style="font-style: italic;">not enough of the good</span> groups (vegetables, fruit & nuts, legumes, fish, cereals) and the <span style="font-style: italic;">good</span> score was 1 for doing the opposite. When these scores are added up, the lowest possible score (bad) is 0 and the highest (good) is 9.<br /></div><br /><div style="text-align: justify;">Now, it turns out that the pattern of scores expected can be modeled by a mathematical probability distribution known as the <a href="http://en.wikipedia.org/wiki/Binomial_distribution">binomial distribution</a>. Strictly speaking, to adopt this model of the situation we need to make two assumptions about the behaviour of the participants. Firstly, we assume that each participant is operating (i.e. choosing foodstuffs and quantities of these to eat) independently of (i.e. not influenced by) each other participant (this is quite likely) and secondly, we need to assume that a participant's scoring on each food group is independent of (i.e. not influenced by) the score of other food groups. This second assumption is not entirely true, for example, it is clear that there would be some correlation between both dairy products and meat & poultry consumption and the monounsaturated/saturated fat ratio. However, for now, let's make this assumption and then we can check whether the actual data support this view.<br /><br />With this model for the scoring process, it becomes possible, given the total number of participants, to calculate the expected numbers with different scores. It is quite easy to see that, given the way the scoring system has been constructed, there will be a full spread of scores, because on every food item, there is a 50-50 chance of scoring 0. Another point to consider is that, with the exception of scores 0 and 9, there are multiple ways of obtaining the other scores. For example, a score of 1 may be obtained by being above the median on one and only one of the 9 food groups - which means there are 9 different ways of getting this score. Whereas a score of 2 may be obtained by combining a score of 1 from 2 out of 9 groups: there are 36 ways of doing this. For the most likely scores of 4 and 5, it can be shown that there are 126 different ways to obtain each of these scores.<br /><br /><a href="http://content.nejm.org/cgi/content/full/348/26/2599/T2">Table 2</a> (and you should look at this table while reading the next bit) in the paper shows the individual food group scores versus the Mediterranean diet score. This table is important because it gives some insight into the raw results of the scoring process which is otherwise obscured because score results for the individuals are grouped into three categories: low diet score (0-3), medium (4-5) and high (6-9). This is distinctly unhelpful and does not let us see how many got each individual score. However we <span style="font-style: italic;">can</span> see – within each diet score category – how many people scored 0 or 1 for a particular food group (i.e. how many people ate more than the median amount and how many ate less than it - or vice versa).<br /><br />Using the binomial distribution and the total number of individuals, it is possible to predict how many people should score 0 or 1 for each food group in the three diet score categories under our assumptions outlined above. (But note that we will get the same prediction for each and every food group because the model makes no distinction between these.) For example, for men in the category of low diet score (0-3), we would expect 2257 individuals and to see only 643 (28%) scoring 1 but 1616 (72%) scoring 0. In the category of medium diet score (4-5) 4378 individuals are expected, with equal numbers scoring 0 and 1 and in the category of high diet score (8-9), we would expect to see 643 of 2257 (28%) scoring 0 and 1616 (72%) scoring 1.<br /><br />How does the prediction compare to the actual values? Quite well in fact for legumes and fruit & nuts (both 23%/77% and 50/50 in the medium score category) and dairy products (31%/69% in the low and high categories and 50/50 in the medium category) not quite so well for fish, vegetables and fat ratio where the ratios are actually 'more extreme' than predicted (18%/82% or 20%/80% in the low and high score categories). Cereals (36%/64%) and meat & poultry show the worst correspondence where the ratios are 'less extreme' than predicted. Overall we slightly overestimate the number in the medium score category (actual number 3808) and underestimate the numbers in the low and high categories.<br /><br /><div style="text-align: justify;">There are some foodstuffs included in Table 2 which are not included in the calculation of the Mediterranean diet score: eggs, potatoes and sweets. As they are not used to calculate the score, it can be expected, that any participant in any diet score group would be equally likely to be above as below the median consumption of these items and so there would be approximately a 50%/50% split in the consumption in each diet score category. A sizeable departure from these figures would suggest that the participant's consumption of these non-scoring foodstuffs is in some way dependent on or linked to consumption of a scoring food group. However, this is clearly not the case, except possibly for potatoes, which show about 16% deviation from the expected 50-50 split in favour of (unsurprisingly) vegetables.<br /><br />This leads to the most notable find in this table - a point which was completely unmentioned in the original article. <span style="font-style: italic;">The distribution of meat and poultry consumption appears to be essentially independent of the Mediterranean diet score.</span> Within each scoring category, the distribution of above and below median consumption for meat and poultry is much more like that of eggs and potatoes and sweets than it is of the other items making up the diet score. Whatever the diet score group, there is close to a 50-50 split in the distribution of individuals' meat consumption. On a Chi-sqared test on the actual versus the expected values, the meat and poultry item shows the strongest result for independence in common with the foodstuffs which <span style="font-style: italic;">are</span> independent of the diet score (e.g. eggs, potatoes, sweets) because they are not used in its calculation. It is interesting that this result is <span style="font-style: italic;">not</span> remarked upon in the paper. In fact, to the contrary, when giving an example based on the link between a 2-point increment in the diet score and improved survival, it is mentioned that such an increment could be achieved by `making a substantial reduction in meat intake' despite the evidence that many high scorers score highly in spite of an above median meat intake!<br /></div></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-69365907065547561162009-04-01T14:16:00.001-07:002009-04-02T15:40:46.792-07:00When epidemiology worksSometimes epidemiology produces a reasonable result. Take this <a href="http://news.bbc.co.uk/2/hi/health/7965380.stm">recent story.</a><br /><br />Researchers note that somewhere has a very high rate of a relatively rare condition. In this case a province of Iran with a high rate of oesophageal cancer. The first step in such a situation is often the <a href="http://en.wikipedia.org/wiki/Case-control_study#Case-control_studies">case control study</a>. This is a study done on the basis of matching people already diagnosed with the condition as closely as possible with controls who do not have the condition and then attempting to find significant ways in which the cases and the controls differ. <a href="http://en.wikipedia.org/wiki/Case-control_study#Problems_with_case-control_studies">Case control studies can be problematic</a> because the results can be manipulated by choice of the controls. Also this type of study is purely observational and it is <span style="font-style: italic;">after the fact</span> observation. You are relying on people's recall and what they recall may be influenced by their present condition - particularly when they have a serious disease. However in this study the results were quite striking:<br /><p></p><blockquote>Compared with drinking warm or lukewarm tea (65C or less), drinking hot tea (65-69C) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70C or more) was associated with an eight-fold increased risk.</blockquote> <p></p> <p></p><blockquote>The speed with which people drank their tea was also important.</blockquote> <p></p> <p></p><blockquote>Drinking a cup of tea in under two minutes straight after it was poured was associated with a five-fold higher risk of cancer compared with drinking tea four or more minutes after being poured.</blockquote> <p></p> <p></p><blockquote>There was no association between the amount of tea consumed and risk of cancer.</blockquote> <p></p>Compare this with the purported increase in <a href="http://news.bbc.co.uk/2/hi/health/7959128.stm">risk of death from eating red meat</a> (based on the responses to one labyrinthine food frequency questionnaire ten years earlier) of about 0.31 times (men) to 0.36 times (women).<br /><br />And what was also nice was that having asked people to estimate how hot they drank their tea, they then went and measured the actual temperature.Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-3192495398712492092009-01-28T13:42:00.000-08:002009-01-28T15:06:30.678-08:00Calorie Restriction and Memory - Low-Carb wins again, actually...<div style="text-align: justify;">This <a href="http://www.pnas.org/content/early/2009/01/26/0808587106.abstract">study</a> is the latest to make <a href="http://news.bbc.co.uk/2/hi/health/7847174.stm">headlines around the world</a> as it is claimed that modest calorie restriction in elderly people can result in an improvement in memory. From the abstract:<br /></div><blockquote style="font-style: italic;"><div style="text-align: justify;">Animal studies suggest that diets low in calories and rich in unsaturated fatty acids (UFA) are beneficial for cognitive function in age. Here, we tested in a prospective interventional design whether the same effects can be induced in humans. ......We found a significant increase in verbal memory scores after caloric restriction .... which was correlated with decreases in fasting plasma levels of insulin....No significant memory changes were observed in the other 2 groups. This interventional trial demonstrates beneficial effects of caloric restriction on memory performance in healthy elderly subjects.</div></blockquote><div style="text-align: justify;">However, what caught my eye in <a href="http://news.bbc.co.uk/2/hi/health/7847174.stm">reports</a> of the study was this:<br /><blockquote><span style="font-style: italic;">However, care was taken to make sure that the volunteers, despite eating a restricted diet in terms of calories, carried on eating the right amount of vitamins and other nutrients.</span><span style="font-style: italic;"><br /></span></blockquote><span><br />Now, this is an important point - it was even - implicitly - used as an objection to the approach by an anonymous dietician who said that:</span><br /></div> <div style="text-align: justify;"><blockquote style="font-style: italic;">....people, particularly those already at normal or low weight, should be "extremely careful" about attempting such a diet. She said: "There is other<span style="display: block;" id="formatbar_Buttons"><span class="on" style="display: block;" id="formatbar_CreateLink" title="Link" onmouseover="ButtonHoverOn(this);" onmouseout="ButtonHoverOff(this);" onmouseup="" onmousedown="CheckFormatting(event);FormatbarButton('richeditorframe', this, 8);ButtonMouseDown(this);"><img src="http://www.blogger.com/img/blank.gif" alt="Link" class="gl_link" border="0" /></span></span> evidence that, far from enhancing memory, dieting or removing meals can interfere with memory and brain function. </blockquote>presumably because it follows that if you just cut calories by 30% you cut nutrition by 30%.<br /></div><br />But these people claim they didn't reduce the subjects intake of vital nutrients, how did they manage this?<br /><br /><div style="text-align: justify;">The truth is revealed in the (rather limited) data in the Table S2 in the <a href="http://www.pnas.org/content/early/2009/01/26/0808587106/suppl/DCSupplemental">supplementary information package.</a><br /></div><span style="font-style: italic;"><br /></span><div style="text-align: justify;"><span>For individuals in the caloric restriction experimental group the mean calories fell from 1843 to 1630, the mean protein intake went from 77g to 71g (all numbers rounded to nearest whole number), the mean fat intake from 70g to 57g and the mean carbohydrate intake from 192g to 74g!! Converted to percent energy measures, this means the mean values went from 17% protein, 35% fat and 43% carbohydrate to 24% protein, 43% fat and 25% carbohydrate (the values don't add to 100% because alcohol intake was included). In other words caloric restriction was achieved, without compromising nutrition, by restricting carbohydrates (especially one imagines typical nutritionally empty carbohydrates like products made mainly of white flour and white sugar).<br /><br />Interestingly, the individuals in the second experimental group which increased its unsaturated fat intake (to 68% of total fat intake on average - that's 36% mono-unsaturated fat which didn't actually increase (baseline for that group was 36%) and 32% polyunsaturates (from 15%)) didn't show the memory improvement, although they also appeared to have achieved a conversion to 'low-carb'. However, in their case the standard deviation for carbohydrate intake was bigger than the mean value (and much larger than the baseline value), which suggests a huge variation within the group.<br /><br />Another caveat is that while taking the mean values of consumption and converting to calories reproduces (to within 40 calories or better) the reported mean caloric intake for the <span style="font-style: italic;">before</span> case in all the groups, it is does <span style="font-weight: bold;">not</span> do so for the <span style="font-style: italic;">after</span> case (the discrepancy is as much as 400 calories - and in all cases the mean nutrient data (in grams) result in an under-estimate of the mean calories). A better model - using a normal distribution for each parameter - might give an idea as to why this is so. Another interesting fact related to this is that - apart from the unsaturated to saturated fat ratio for the unsaturated fatty acid experimental group, none of the reported differences in <span style="font-style: italic;">before</span> and <span style="font-style: italic;">after</span> macronutrient mean intakes were reported as significant.<br /><br />To sum up: the calorie restriction appears to have been mainly achieved by restricting carbohydrates. The researchers claimed that they had achieved calorie restriction without reducing nutrient content of the diet. The only way to do this is by removing or significantly reducing nutritionally empty carbs e.g. see <a href="http://www.freetheanimal.com/root/2009/01/vitamin-supplements-part-three.html">here</a>. Mean dietary data reported from the study lends support to this theory. The results observed in the subjects e.g. reduced insulin levels also support this theory.<br /></span></div><span style="font-style: italic;"><br /><br /></span><blockquote><span style="font-style: italic;"></span><div style="text-align: left;"><span style="font-style: italic;"><blockquote><br /></blockquote></span></div><span style="font-style: italic;"><blockquote></blockquote></span><div style="text-align: left;"><span style="font-style: italic;"></span><blockquote></blockquote><br /><span style="font-style: italic;"></span></div> </blockquote>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-64799464169213034082008-12-07T08:39:00.000-08:002009-04-25T08:33:22.938-07:00Lark Rise - Discussion<div style="text-align: justify;">The book Lark Rise <a href="http://http//talkingfood.blogspot.com/2008_12_01_archive.html">documents the apparent good health and long lives of nineteenth century rural labourers despite a physically demanding lifestyle</a>, a life of considerable material poverty relative to today and less medical support than is available today. The testimony of this book is backed up by my own observations of mortality and lifespans while doing family history research. What could be the explanation?<br /><br />The first that springs to mind is that the author is simply mistaken; that her recollection is clouded by time, by the rosy glow of the <span style="font-style: italic;">good old days</span>. However, the author herself seems aware of this possibility and her own seeking for an explanation suggests that, as far as she can tell, she is recalling fact and not invention.<br /><br />It's likely that one of the reasons the doctor was seen so rarely was due to the cost. In those days there was no <a href="http://www.nhshistory.net/intro1.htm">NHS</a>. A doctor's services had to be paid for although it is claimed that wealthy doctors also treated patients who were unable to pay for free and many hospitals were charitable institutions and free to the poor (see for example, discussion in the following books: <span style="font-style: italic;">Sociology as applied to medicine</span> by Graham Scrambler, Elsevier, 2008 and <span style="font-style: italic;">Social policy and welfare</span> by Walsh, Stephens and Moore, Nelson Thornes, 2000, both available on <a href="http://books.google.ie/books">Google books</a>). However, it seems likely that the doctor was only called in when absolutely necessary. People might have treated less serious complaints themselves and put up with chronic conditions and pain such as arthritis.<br /><br />Assuming then that this does show that serious disease - such as cancer - was largely absent what is the reason for this generally robust health and long life?<br /><br />First and foremost, probably <a href="http://www.grassrootshealth.net/">vitamin D</a>: - children were sent outside to play every day, labourers worked outdoors. Pork meat and fat was a major component of the diet and the pigs were kept outside and fed a diet of scraps, milk and vegetable matter which would have been notably deficient in soy and corn (i.e. maize, because in nineteenth century England, <span style="font-style: italic;">corn</span> meant wheat)! Thus, the lard obtained likely would have been as high in vitamin D as it is possible for lard to be and probably lower in omega-6 polyunsaturates than today's. Thus the diet would have been better balanced in the omega-6/omega-3 ratio.<br /><br />Meat was eaten daily and, even if only once a day, because of the way nothing was wasted and everything cooked in one pot, the goodness (minerals, gelatine) from meat and bone juices would have been eaten up by the children, soaked into the bread or pudding. In addition, it appears that fish was eaten weekly (the fishmonger called weekly) and fish roe was prized and preferentially given to children.<br /><br />Although many fruits and vegetables we habitually eat today (oranges, bananas, tomatoes) were absent. Other, native green plants (e.g. sorrel, nettle, dandelion, goose grass and many more are all edible) were taken from the wild and eaten. (It is in fact to this that the author herself attributes the good health of the hamlet.)<br /><br />Finally, the bread was made from stoneground wheat. It is widely believed that this is more nutritious than today's refined white flours. But, it's not as clear cut as it seems.<br /><br />On the one hand, white flour is very low in nutrients compared to wholemeal (see <a href="http://www.westonaprice.org/modernfood/wheatyindiscretions.html">here</a> for the effects of modern processing on flour). From <a href="http://www.fitday.com/">Fitday</a>, all-purpose white wheat flour unenriched has the following micronutrient profile (as a percentage of daily allowance)<br /><br /><table><tbody><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin A</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Calcium</div></td><td class="Prct"><div class="Float">2</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin D</div></td><td class="Prct"><div>0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Thiamin</div></td><td class="Prct"><div class="Float">10</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Niacin</div></td><td class="Prct"><div class="Float">8</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin B6</div></td><td class="Prct"><div class="Float">3</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Phosphorus</div></td><td class="Prct"><div class="Float">14</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Selenium</div></td><td class="Prct"><div class="Float">61</div></td><td>%</td></tr></tbody></table><table><tbody><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin C</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Iron</div></td><td class="Prct"><div class="Float">8</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin E</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Riboflavin</div></td><td class="Prct"><div class="Float">3</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin B12</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Manganese</div></td><td class="Prct"><div class="Float">43</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Copper</div></td><td class="Prct"><div class="Float">9</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Magnesium</div></td><td class="Prct"><div class="Float">7</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Zinc</div></td><td class="Prct"><div class="Float">6</div></td><td>%</td></tr></tbody></table><br />whereas whole wheat flour has much more Iron, B vitamins and other minerals.<br /><br /><table><tbody><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin A</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Calcium</div></td><td class="Prct"><div class="Float">4</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin D</div></td><td class="Prct"><div>0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Thiamin</div></td><td class="Prct"><div class="Float">36</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Niacin</div></td><td class="Prct"><div class="Float">38</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin B6</div></td><td class="Prct"><div class="Float">20</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Phosphorus</div></td><td class="Prct"><div class="Float">42</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Selenium</div></td><td class="Prct"><div class="Float">121</div></td><td>%</td></tr></tbody></table><table><tbody><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin C</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Iron</div></td><td class="Prct"><div class="Float">26</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin E</div></td><td class="Prct"><div class="Float">5</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Riboflavin</div></td><td class="Prct"><div class="Float">15</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Vitamin B12</div></td><td class="Prct"><div class="Float">0</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Manganese</div></td><td class="Prct"><div class="Float">228</div></td><td>%<span style="display: block;" id="formatbar_Buttons"><span class="on" style="display: block;" id="formatbar_CreateLink" title="Link" onmouseover="ButtonHoverOn(this);" onmouseout="ButtonHoverOff(this);" onmouseup="" onmousedown="CheckFormatting(event);FormatbarButton('richeditorframe', this, 8);ButtonMouseDown(this);"><img src="http://www.blogger.com/img/blank.gif" alt="Link" class="gl_link" border="0" /></span></span></td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Copper</div></td><td class="Prct"><div class="Float">23</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Magnesium</div></td><td class="Prct"><div class="Float">41</div></td><td>%</td></tr><tr class="View_FoodLabelDvRow"><td class="Name"><div>Zinc</div></td><td class="Prct"><div class="Float">23</div></td><td>%</td></tr></tbody></table><br />But without neutralization of the phytate content of the wholemeal flour, much of this nutritional content, particularly the minerals, cannot be absorbed [1] (see also the discussion of White Flour vs Whole Wheat <a href="http://www.practicallyedible.com/edible.nsf/Index/flour">here</a>). There is also the question of its effect on <a href="http://www.practicallyedible.com/edible.nsf/pages/stonegroundflour">teeth</a>. There are also other 'anti-nutrients' in whole grains - see for example <a href="http://www.westonaprice.org/foodfeatures/be_kind.html">here</a>.<br /><br />However, it's possible that, as the bread was made at home, it was actually a sourdough bread. In this case the effects of anti-nutrients (lectins and leptins) and phytate would have been partially neutralized by the longer fermentation. (Stephan on <a href="http://wholehealthsource.blogspot.com/">Whole Health Source</a> has many posts on this issue.)<br /><br /><br />[1] McGee, H. On Food and Cooking, London: Unwin Hyman Ltd, 1984.<br /><br /><br /><br /><br /><br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-9824609418285572362008-12-05T14:42:00.001-08:002008-12-07T08:39:14.151-08:00Lard in Lark Rise<div style="text-align: justify;">I'm very keen on researching my family history, and recently I've been working on the predecessors of one great-grandmother who were all East Anglian <a href="http://http//www.genuki.org.uk/big/Occupations.html">'ag labs'</a> (agricultural labourers). I noticed an interesting thing about them: in the nineteenth century particularly, very many of them lived to a ripe old age. Even going back to individuals born in the middle of the eighteenth century, I can find more than a few - across different families - who lived into their late 70s and 80s. Why is this so? They were poor, they didn't have access to modern medical care and they worked hard physically.<br /><br />One book which sheds light on this is <a href="http://en.wikipedia.org/wiki/Lark_Rise_to_Candleford">Lark Rise to Candleford</a>*, the first part of which was published by Flora Thompson in 1939. It is a novel/memoir of her childhood in a rural England (Oxfordshire) which even then was passing out of existence. By the 1880s, when Flora and my great-grandmother (living a similar life in Cambridgeshire) were growing up, the industrial revolution in Britain was a hundred years old, but in the agricultural sector machine power was only just beginning to replace manpower and horse-power. Hamlets and small villages were populated still by agricultural labourers, living in cottages which came with the job, and working for the local farmer. The farms were mixed farms, in the area Thomson grew up, they were mostly arable with some livestock. The weekly wage would not normally have been enough for such large families not to starve, but they survived and even thrived in the rural setting as they had the opportunity to provide for themselves: an opportunity denied to poor families in town. Indeed, Thomson notes that the general opinion of those in her village of the nearest big town, Oxford, was that although a man might earn more there, as he'd be paying more rent and would<br /><blockquote></blockquote><span style="font-style: italic;"><blockquote>have nowhere to keep a pig or to grow many vegetables, he'd be a fool to go there. (p. 33)</blockquote></span>Thomson refers to the adult generation of the 1880s as 'The Beseiged Generation'. The term seems to be meant in two ways: firstly, it was a period just before enormous change. Although the social structures of the time were to hold for at least another thirty years (until after the Great War) and to a lesser extent for sixty more, not collapsing completely until after the Second World War, the big change in agriculture and the start of the inexorable decline in manpower on the land was just around the corner. Maybe it is just a coincidence, maybe it is a consequence of the initial impact of small changes, innovations, where before, for so many years, there were none, but it was a time of decaying tradition and custom. For example, she says of the herb garden:<br /><blockquote></blockquote><blockquote></blockquote><blockquote style="font-style: italic;">As well as the garden herbs, still in general use, some of the older women used wild ones, ..... But the knowledge and use of these was dying out; (p. 115).</blockquote><blockquote style="font-style: italic;"></blockquote> Secondly, it was a tough time economically, the agricultural wage of the 1880s was 10 shillings per week (<a href="http://www.measuringworth.com/ppoweruk/?redirurl=calculators/ppoweruk/">equivalent</a> to £258 per week today) and every way possible had to be used to feed, shelter and clothe a large family (and they did have large families, my great-grandmother was the 1oth of 11 children).<br /><br />So why were they apparently so healthy? Indeed, the author herself seems somewhat pushed to explain the robust good health of the hamlet she remembers. She says:<br /><blockquote style="font-style: italic;">There were two epidemics of measles during the decade, ... but, for years together, the doctor was only seen there when one of the ancients was dying of old age, or [for] some difficult first confinement... There was .... except for a few months when a poor woman was dying of cancer, no invalid. (p.19)</blockquote><span style="font-weight: bold;">What They Ate</span><br />The staples of the diet were bread, lard and bacon. Every household raised and killed one or two pigs each year. The importance of the pig was shown by the amount of effort lavished on their care and feeding. They were given not only household scraps (if there were any) but specially cooked up meals of potatoes mixed with leftover cooking liquor, milk and barley meal. Children gathered weeds and grass or even snails to supplement the pig's diet. Often half the pig had to be 'mortgaged' to the baker or publican as a way of buying on credit the necessary pig fattening food.<br /><br />Only one meal a day would have any meat. As an agricultural labourer's house did not have an oven, nor even a range, cooking was done in the fireplace in an iron pot slung from a rack or chain built into the lower part of the front of the chimney piece. This arrangement meant everything was cooked (boiled) together: bacon, green vegetables kept together in a net, potatoes in another net and a <a href="http://thefoody.com/pudding/rolypoly.html">roly-poly pudding</a> greased and floured and wrapped in a pudding cloth. (This last is a peculiarly English creation being a flour and suet or lard dough adaptable to either sweet, if fruit, currants or jam are added, or savoury purposes, if meat.) All that was necessary was careful timing of when to put in and take out the various components. There were no leftovers for the pig, save the vegetable and potato peelings and the cooking water.<br /><br /><div style="text-align: justify;"> The other two meals (breakfast and lunch) were bread and butter (rarely) or bread and lard. According to Thomson, butter was expensive, although cheaper in the summer when a pound cost tenpence, and the cheaper imitation 'butterine', presumably an early form of margarine, was not liked. Instead they collected their own lard from their pigs and flavoured it with rosemary from the garden. Rosemary did not just improve the flavour. Herbs such as rosemary and sage have anti-oxidant properties and help to prevent the unsaturated fatty acids in the lard from going rancid ([1], p.606) as it had to last until the next pig killing, an important consideration in houses which had no refrigeration.<br /></div><br />The pig killing was an important event and was followed by a celebratory 'pig feast' to which the extended familly was invited. The feast featured "joints of pork, potatoes, batter puddings, pork pies, and sometimes a cake or two" [to take advantage of the opportunity of using the baker's oven] (p. 27) plus three or four different kinds of vegetables and a meat pudding.<br /><blockquote style="font-style: italic;">At the pig feast here would be no sweet pudding, for that could be had any day, and who wanted sweet things when there was plenty of meat to be had! (p. 27).</blockquote>This statement is one of the most remarkable in the whole book: it would be hard for today's children to understand.<br /><br />Nothing from the pig was wasted: home-cured bacons and hams kept the family provided throughout the winter and beyond (depending of course on the size of the family and whether half the pig was already spoken for!), 'hog puddings' were also made (from the pig's blood) and the <a href="http://en.wikipedia.org/wiki/Chitterlings">chitterlings</a> were made into sausages after they had been rinsed under running water for three days.<br /><br />Throughout the year, the main meat to be had was the preserved, salted and dried bacon and ham. Once a week, there would be a small amount of meat bought ("six-pennyworth of pieces") made go further by making a meat pudding. Even less often a small joint would be roasted "on a string before the fire" or used as a pot-roast, cooked with lard in a saucepan over the same fire. A "<a href="http://en.wikipedia.org/wiki/Toad_in_the_hole">toad</a>", the meat wrapped in a suet [pastry] crust and boiled over the fire would again make a small joint go farther and make sure the precious meat juices were not wasted.<br /><br />Bread was bought, but the women also needed flour - to make the puddings which were otherwise the way of eking out a meagre supply of meat. This flour was obtained by the right of the labourers to the leazings: the heads of grain left behind in the field from the less efficient time before mechanical harvesting. For two to three weeks once harvesting was over, the women and children went out to the stubbly fields each day, collecting by hand the leftover ears of wheat. Once threshed by hand at home, it was taken to the local mill and a large sack of flour returned:<br /><blockquote><span style="font-style: italic;">one bushel, two bushels, or even more, in large, industrious families. (p.28)</span> </blockquote>It would have been stone ground flour too, at least at the beginning of the decade (of which more later).<br /><br />Just as the pig was home-raised, vegetables and fruits were also home-grown. The men tended allotments (parcels of land granted to them, probably as part of the cottage rental to allow them to grow food crops) where they grew potatoes and wheat or barley. In the cottage garden they grew vegetables and fruits: peas, cabbages, cauliflowers, kale, beans and potatoes, fresh greens, radishes and onions. Rhubarb, currants and gooseberries would be made into jam. They had the advantage of fresh and organic produce. They also did not waste the natural produce around them. Children went out gathering mushrooms; sloes, blackberries and elderberries could be made into jams or jellies - or brewed into wine.<br /><br />Nevertheless, there were occasional variations to the diet. Eggs were eaten, but only when affordable or only by those who kept chickens. Milk was available, at very low cost, if you walked the mile and a half to the farmhouse. It was hand-skimmed, so some cream was left and it was raw. Interestingly, she says that most people did not bother and so most children did not drink milk once they were weaned.<br /><br />A travelling fishmonger who also sold fruit called weekly. If it could be afforded a <a href="http://en.wiktionary.org/wiki/bloater">bloater</a> would be bought for a penny, "but it had to be a soft-roed one, for, in nearly every house there were children under school age at home; so the bloater had to be shared, and the soft roes spread upon bread for the smallest ones." (p. 119). Oranges and, on one occasion, a tomato bought from this vendor were merely curiosities, tried out once.<br /><br />Small birds were another frequent and popular addition. Older boys would go out at night and net groups of sparrows where they were nesting in the hedgerows. These could be plucked and put into a pudding. One or two would be toasted over the fire. Women and children also lured and trapped birds. To take anything bigger than a sparrow or a blackbird or thrush, even to pick up a dead hare, was poaching. But it was done, not habitually, but if the opportunity should arise.<br /><br />* My edition of the book is: Flora Thompson, <span style="font-style: italic;">Lark Rise to Candleford, </span>Penguin Modern Classics, Penguin Books, 1973.<br /><br />[1] McGee, H. On Food and Cooking, London: Unwin Hyman Ltd, 1984.<br /><br /><br /><br /><br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-41440974683095584282008-11-21T14:42:00.000-08:002008-11-21T15:09:05.151-08:00LCHP Part 2 - the punchline<div style="text-align: justify;">It’s all very well to show that the <a href="http://www.nature.com/ejcn/journal/v61/n5/abs/1602557a.html">LCHP (LowCarbohydrate-HighProtein) score</a> doesn’t completely and accurately reflect protein and carbohydrate intake, but what about the claimed results of an increased risk of mortality with an increasing score?<br /></div><br /><span style="font-style: italic;">How was the relationship to mortality calculated?</span><br /><div style="text-align: justify;">The relationship to mortality was calculated through <a href="http://www.statsoft.com/textbook/stsurvan.html#rcox">Cox proportional hazards models</a> which are used to relate the risk of death with either the deciles of nutrient intake or the LCHP score, taking into account confounding factors (gender, age, socioeconomic status, smoking, BMI, physical activity, alcohol consumption). One thing to note about Cox proportional hazards models is that they represent the assumption of a model in which the thing being investigated (in this case carbohydrate vs. protein consumption) is being assumed to be <span style="font-weight: bold;">directly causal</span> in the decease of the affected individual. Cox models were originally used in drug and treatment trials where a terminally-ill patient’s survival might be expected to vary directly – and over a relatively short time-period (months to only a few years) depending on whether they were receiving drug or placebo. While it is likely that diet does have an impact on mortality, it is not at all clear that the link is as direct and immediate as assumed by these models.<br /></div><br /><div style="text-align: justify;">Four different models (i.e. essentially differently constructed equations) were used to hunt for links between the supposed diet culprits – low carb/high protein – and death. In model 1 (not energy adjusted), increased protein intake (per decile) was found to be significantly linked to increased mortality (1.13 increased risk, CI: 1.03-1.23). However, as protein intake was the best predictor of total energy intake (correlation coefficient 0.93) it is likely that the one is a proxy for the other and the authors note that<br /><br /></div>‘mortality … increased with … total energy intake’ (p.577)<blockquote></blockquote><div style="text-align: justify;">Model 2 assessed the LCHP score but found that an association with increased risk of mortality was non-significant (P=0.14; CI: 0.97-1.20). Model 3 looked at energy-adjusted individual nutrient intake and found that energy-adjusted carbohydrate intake was inversely related to mortality: reduced risk 0.94 (CI:0.89-0.99) but the apparent link with protein had disappeared (possibly because of the energy-adjustment). However, according to the authors, <span style="font-style: italic;">this model is flawed because it does not take into account</span><br /><blockquote>‘the complementary changes that have to be introduced for the preservation of total energy intake, when carbohydrates and proteins change’ (p.578). </blockquote><br /><div style="text-align: justify;">Most interesting is model 4 which finds a significant relationship between the LHCP (using energy-adjusted protein/carb deciles) and mortality (increased risk 1.08 CI:1.03-1.13, P=0.001). What this actually means is that increased mortality is associated with a decreased fat intake! Yes, because a 2-point increase in the LCHP score is caused 57% of the time by increasing intake of protein <span style="font-style: italic;">and/or</span> carb. In an energy-adjusted formulation, when one or more macronutrients is increased, then necessarily the others decrease – as a proportion of energy intake – so what this finding may really be telling us is that – <span style="font-weight: bold;">as fat intake declines as a proportion of energy, mortality increases!</span><br /></div></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-79835086788268991352008-11-08T16:40:00.000-08:002008-11-09T12:42:30.348-08:00Interlude: the LCHP (LowCarbHighProtein) score<span style="display: block;" id="formatbar_Buttons"><span class="" style="display: block;" id="formatbar_CreateLink" title="Link" onmouseover="ButtonHoverOn(this);" onmouseout="ButtonHoverOff(this);" onmouseup="" onmousedown="CheckFormatting(event);FormatbarButton('richeditorframe', this, 8);ButtonMouseDown(this);"><img src="http://www.blogger.com/img/blank.gif" alt="Link" class="gl_link" border="0" /></span></span><br /><div style="text-align: justify;">Oh, dear, they’ve been at it again. Someone asked about this <a href="http://www.nature.com/ejcn/journal/v61/n5/abs/1602557a.html">study</a> on <a href="http://www.proteinpower.com/drmike/">Dr Eades’ boog</a> and I decided to take a look. I have to admit I’d been avoiding it because of a bit of cognitive dissonance due to the conclusion touted in the abstract:<br /></div><blockquote>In models with energy adjustment, higher intake of carbohydrates was associated with significant reduction of total mortality,… Even more predictive of higher mortality were high values of the additive low carbohydrate-high protein score (per 5 units, mortality ratio 1.22 with 95% CI 1.09-to 1.36). Positive associations of this score were noted with respect to both cardiovascular and cancer mortality.</blockquote>Sounds scary, doesn’t it – has it been discovered lower carb/higher protein diets are really bad for us after all? Well, no not really – once you look into this low carbohydrate-high protein score (hereafter abbreviated as LCHP) it turns out they’re not measuring quite what they think they are…. So read on.<br /><div style="text-align: justify;"><br />This study is based on the same cohort of Greek EPIC participants as used in the famous <a href="http://content.nejm.org/cgi/content/full/348/26/2599">Mediterranean diet study</a>. As such food consumption data is based on food frequency questionnaire data – albeit interviewer administered – with all the caveats that appy to that . The 22944 subjects were followed until December 2003 – not quite 5 years on average – but making 113230 person-years. However, there were only 455 deaths. This makes 22944 a <a href="http://www.numberwatch.co.uk/trojan_number.htm">trojan number</a> because although the comparison is done on the 455 with the much larger group of 22489 survivors, data is effectively only available relating diet to death for 455 people.<br /><br /><span style="font-weight: bold;">How was the LCHP score calculated?</span><br />The key to the study is how the LCHP score is calculated. The study participants are classified by deciles (10% steps) of ascending protein intake and descending carbohydrate intake. For example: let’s say the range of protein intake was 50-90g: a decile is 4g; so protein intake of 50-54g would be assigned a score of 1, 54-58g – assigned a score of 2, and so on. Carbohydrate intake is scored in reverse order, so that a score of 1 indicates the highest decile of consumption and 10 the lowest. The additive LCHP is then created by adding the two scores together. Or as they put it:<br /><blockquote>Thus, a subject with LC/HP score 2 is one with very high consumption of carbohydrates and very low consumption of protein, whereas a subject with score 20 is one with very low consumption of carbohydrates and very high consumption of protein.</blockquote><span style="font-style: italic;">However, as we shall see – this isn’t quite how it works.<br /><br /></span>Imagine we have 10 individuals with protein consumption that puts each one of them into a different protein decile. So we score these individuals<br /><blockquote>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]</blockquote><br />Now these same 10 individuals also have the carbohydrate consumption so that their carbohydrate scores are:<br /><blockquote>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]</blockquote><br />Adding these together, these individuals have LCHP scores:<br /><blockquote>[2, 4, 6, 8, 10, 12, 14, 16, 18, 20]</blockquote>But what if we had another 10 individuals with the same protein scores but different carbohydrate consumption –so that they scored respectively [2, 3, 4, 5, 6, 7, 8, 9, 10, 1] ? These individuals’ LCHP scores would be: [3, 5, 7, 9, 11, 13, 15, 17, 19, 11]. In the second group someone in the highest decile of protein consumption had a final LCHP of 11 because their carbohydrate consumption was also high. What about the other person with an LCHP of 11 in that group? They had middling consumption of each.<br /><br />In fact for any individual with a protein score of 1 – their carb score could be anywhere from 1 to 10 – giving them a LCHP of anywhere from 2 to 11. Any individual with a protein score of 2, could score an LCHP from 3 to 12 and so on. You might argue that you can’t increase both protein and carbohydrate – but when comparing individuals like this you can – because consumption also depends on other factors such as weight, age, gender, activity level. <span style="font-style: italic;">There has been no consideration here that there is a certain minimum requirement of protein for health</span> (usually expressed as at least 0.5 -1g/ kg body weight) and it doesn’t follow that if one macro-nutrient goes up, the other always goes down because fat is a third variable in the equation which can also be manipulated by the eater and which is left unconsidered in this score.<br /><br /><span style="font-weight: bold;">Another problem</span><br />The second problem with the score concerns what the detail of what differs between two individuals with different scores. Consider an individual with what is clearly considered to be a ‘low’ score by the authors – 6. This can be made up from these possible combinations of protein + carb deciles:<br /><blockquote>1 + 5, 2 + 4, 3 + 3, 4 + 2, 5 + 1</blockquote>Let’s say this person has 3+3: a quite low (only 3rd decile) protein consumption and a quite high carb intake too. Now, someone else has a LCHP score 2 points higher, i.e. 8. This can be made up of these possible combinations of protein + carb:<br /><blockquote>1 + 7, 2 + 6, 3 + 5, 4 + 4, 5 + 3, 6 + 2, 7 + 1 </blockquote>Now, if the second person’s score was 4+4 – we could say that yes they had higher protein and lower carb intake. But what if their score was 6+2? Then they would indeed have a higher protein intake but also a higher carb intake. On the other hand if their score was 2+6, they would have a much lower carb intake but also a lower protein intake. In fact, for a difference between scores of 2 points, there are: 5 differences due to increasing protein intake only, 5 due to decreasing carb intake only, 5 due to increasing protein and decreasing carb, 10 due to either <span style="font-style: italic;">increasing</span> <span style="font-style: italic;">both</span> protein and carb and 10 due to <span style="font-style: italic;">decreasing</span> <span style="font-style: italic;">both</span> protein and carb! Hence 20/35 or <span style="font-style: italic;">57.1% of the possible score differences could involve a change in what is considered to be a ‘good’ direction</span> <span style="font-style: italic;">of one component</span> of the score (increasing carb or decreasing protein). A further 10/35 or <span style="font-style: italic;">28.6% involve no change in one component</span> of the score. Only 5/35 or 14.3% involve the typical 'increased protein and decreased carb' posited by the authors!<br /><br />For evidence that this ambiguity really does exist, one need look no further than Table 2 in the paper where the correlation coefficients between various measures used in the paper are given. They show that the <span style="font-style: italic;">correlation between the LCHP score and protein consumption is only 0.32</span> (0.28 when energy-adjusted) and only <span style="font-style: italic;">-0.31 (-0.31 when energy-adjusted) for carbohydrates</span>! Compare this with the correlation between protein and carbohydrate consumption which is 0.78. This suggests protein and carbohydrate consumption tend to move together strongly whereas changes in the LCHP score only very weakly reflect changes in protein and carbohydrate consumption!<br /><br />This problem of working out exactly what numbers contribute to the differences between two LCHP scores is in fact a very complex mathematical problem belonging to the field of combinatorics and was probably not foreseen by the creators of the score! However, it hugely muddles the interpretation of the 'results'.<br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0tag:blogger.com,1999:blog-4875772119187826663.post-8912794153804428482008-10-04T07:17:00.000-07:002009-04-25T13:40:34.744-07:00Un-picking the Mediterranean diet [score]<div style="text-align: justify;">The Mediterranean diet has been in the news again with the release of <a href="http://content.nejm.org/cgi/content/full/359/3/229">a study </a> that pits it against a low-fat diet (the standard AHA recommendation) and a low-carb diet. But, I'm not going to talk about that. I'm actually a bit obsessed with the whole idea of the <a href="http://content.nejm.org/cgi/content/full/348/26/2599">Mediterranean diet score</a>. I think it's got something to do with the way it makes it all seem simple - as in a diet book approach you adjust your diet by tweaking your diet score - yet it's scientific - because some researchers have used this score to prove that if you keep your score high enough you will live longer!<br />The Mediterranean diet is usually described as emphasizing legumes, fish, olive oil and lots of fruit and vegetables and is supposed to represent the kind of healthy diet typical of those who live in the sun-drenched regions around the Mediterranean sea. In fact, of course, there are lots of different <span style="font-style: italic;">real</span> Mediterranean diets: French, Spanish, Italian, Greek and so on. So what is the Mediterranean diet as it exists in the mind of nutrition researchers? The Mediterranean diet concept was launched with a <a href="http://content.nejm.org/cgi/content/full/348/26/2599">study</a> that declared that<br /></div><span style="font-style: italic;"><blockquote>A higher degree of adherence to the Mediterranean diet was associated with a reduction in total mortality (adjusted hazard ratio for death associated with a two-point increment in the Mediterranean-diet score,</blockquote></span><div style="text-align: justify;">The Mediterranean diet score described in that study was based on a Greek diet. The researchers studied the dietary intake of elderly Greeks using Food Frequency Questionnaires and based on the results from that came up with <span style=""> 14 <span>"food groups</span>" : potatoes, vegetables, legumes, fruits and nuts, dairy products, cereals, meat, fish, eggs, monounsaturated lipids (i.e. olive oil), polyunsaturated lipids (vegetable-seed oils), saturated lipids and magarines, sugar and sweets, nonalcoholic beverages.<br /><br /></span></div><div style="text-align: justify;">These food groups already reflect the preoccupations of researchers. Why for instance are potatoes considered a separate group from vegetables? Aren't potatoes a vegetable? Is it because potatoes are starchy tubers? Well, presumably not, because it's <span style="font-style: italic;">only</span> potatoes; other starchy root vegetables such as carrots and parsnips are not similarly singled out. Is it because potatoes <a href="http://en.wikipedia.org/wiki/Potato">contain enough nutrients apart from the starch</a> to act as a staple crop just like cereals (in fact better than cereals) ? Probably not. My personal answer to this question is that it is because potatoes can be made into chips and crisps and therefore potatoes are (as every nutritionist knows) most definitely not a vegetable.<br /><br />The diet score itself was based on only 9 out of these 14 "groups": vegetables, fruits and nuts, legumes, meat, fish, dairy products, cereals, monounsaturated to saturated fat intake ratio and alcohol consumption. (Why did they pick these and leave out potatoes, eggs, sugar and sweets and nonalcoholic beverages? Who knows? I can hazard a guess though: it reflects the obsession of <span style="font-style: italic;">fat bad: carbs good)</span> and the actual diet score was worked out as follows:<br /><ul><li>for the items considered beneficial or 'good' (vegetables, fruits and nuts, legumes, fish, cereals, high monounsaturated fat ratio) a score of <span style="font-weight: bold;">+1</span> was given if the individual consumed <span style="font-weight: bold;">more</span>;<br /></li><li>for the items considered harmful or 'bad' (meat, dairy products, alcohol) a score of <span style="font-weight: bold;">+1</span> was given if the individual consumed <span style="font-weight: bold;">less</span>. </li></ul>More or less than what? What was the dividing line? Well, that is the interesting bit: the dividing line was the 'middling' consumption of the cohort, i.e. the <a href="http://en.wikipedia.org/wiki/Median">median</a>. [Given the whole range of consumption values for each item, the median is simply the value exactly in the middle, with 50% of values above it and 50% below.] This of course has the obvious result, that for every item, immediately, the study population separates out into sheep and goats: the sheep who are on the right side of the median (even by 1 gram!) and the goats who are on the wrong side!</div><br />So what was the 'middling' Mediterranean diet?<br />You can see it for men and women in <a href="http://content.nejm.org/cgi/content/full/348/26/2599/T2">this table</a>.<br /><br /><div style="text-align: justify;">To investigate what this means in terms of macronutrient ratios, I used <a href="http://www.fitday.com/WebFit/Index.html"> Fitday </a>to simulate these median diets as follows: for <span style="font-style: italic;">vegetables</span> I included a combination of zucchini, peppers, aubergines and salad vegetables: lettuce, cucumber, tomatoes; for <span style="font-style: italic;">fruits</span>: apricots, apples, oranges and bananas and nuts: almonds and pistachios. <span style="font-style: italic;">Fruits and nuts</span> were combined as 95% fruit and 5% nuts – this was adjusted to get the resulting fat intakes close to the actually recorded values. For <span style="font-style: italic;">dairy</span>, I used 60% wholemilk plain yoghurt and 40% (full-fat) feta cheese. For <span style="font-style: italic;">meat</span>, a 50/50 combination of lamb and poultry and for <span style="font-style: italic;">fish</span>, <a href="http://kalofagas.blogspot.com/2008/06/marinated-red-mullet.html%E2%80%9D"> red mullet</a>. The <span style="font-style: italic;">legumes</span> were kidney beans and the representative <span style="font-style: italic;">sweets</span> I chose was halvah. (After all what does <span style="font-style: italic;">sweets</span> represent? Desserts? Or just confectionary?) Nonalcoholic <span style="font-style: italic;">beverages</span> were a mix of fruit juices, soft drinks and tea. <span style="font-style: italic;">Cereals</span> included were bread, crackers, cornflakes and filo pastry, oh and a representative biscuit – as it was explicitly stated that <span style="font-style: italic;">biscuits</span> were included under <span style="font-style: italic;">cereals</span> (and not under <span style="font-style: italic;">sweets</span> for example).<br /></div><div style="text-align: justify;">As a check of my methods I compared my 'results' with the recorded fat intakes: I came out pretty close to the actual results:<br /></div><table><tbody><tr><th><br /></th><th> Total kcal </th> <th> Sat Fat (g) </th> <th> PUFA (g) </th><th> Monounsat (g)</th><br /></tr><br /><tr><th>Men </th><br /></tr><tr><td>Calculated</td><td>2290.2</td><td>32.5</td><td> 15.7</td><td>57.7</td></tr><br /><tr><td>actual </td><td> 2354.5 </td><td>33.1</td><td>15.0</td><td>55.9<br /></td></tr><br /><tr><th>Women </th></tr><br /><tr><td>Calculated </td><td> 1933.9</td><td> 28.7 </td><td> 13.3 </td><td> 49.2</td></tr><br /><tr><td>actual </td><td> 1863.0 </td><td> 27.0 </td><td> 12.6 </td><td> 46.5</td></tr></tbody></table><br /><br />And the macronutrient ratios of such a diet?<br /><table><tbody><tr><th><br /></th><th> Protein </th><th> Fat </th><th> Carb</th></tr><br /><tr><td>Men </td><td> 14.56% </td><td> 43.22% </td><td> 42.23%<br /></td></tr><tr><td>Women </td><td> 14.23% </td><td> 44.00% </td><td> 41.77%</td></tr></tbody></table><br /><div style="text-align: justify;">Grams of carbs per day were were <span style="font-style: italic;">220g for men and 183g for women</span> – not low-carb. Most of the carb intake does come from the cereals group – but how does this compare to the typical diet pyramid recommendation? The <a href="http://www.mypyramidtracker.gov/">diet pyramid</a> recommendation is for 5-6 "oz grain equivalents" per day for women and 6-8 per day for men (the variation is due to age). A "1 oz grain equivalent" is a slice of bread, a cup of breakfast cereal, ½ cup of cooked rice or pasta. Calculating a combination of these for our median individuals gives a requirement to eat about <span style="font-style: italic;">450g of cereals per day for men and about 340g per day for women</span> – as you can see our Mediterraneans (177.7 g/day for men and 139.7g/day for women) are quite far from this ideal!<br /></div><br /><div style="text-align: justify;">One final thing to note is that the proportion of fat in the actual Mediterranean diet as evidenced above is considerably more than was recommended in the recent <a href="http://content.nejm.org/cgi/content/full/359/3/229">diet study</a> where it was restricted to 35% or less.<br /></div>Jacquelinehttp://www.blogger.com/profile/09429343452823881929noreply@blogger.com0