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there is hope... new article in scientific american

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  • there is hope... new article in scientific american

    In 2008 Stampfer co-authored a study in the New England Journal of Medicine that followed 322 moderately obese individuals for two years as they adopted one of three diets: a low-fat, calorie-restricted diet based on American Heart Association guidelines; a Mediterranean, restricted-calorie diet rich in vegetables and low in red meat; and a low-carbohydrate, nonrestricted-calorie diet. Although the subjects on the low-carb diet ate the most saturated fat, they ended up with the healthiest ratio of HDL to LDL cholesterol and lost twice as much weight as their low-fat-eating counterparts.
    and this one:

    Will the more recent thinking on fats and carbs be reflected in the 2010 federal Dietary Guidelines for Americans, updated once every five years? It depends on the strength of the evidence, explains Robert C. Post, deputy director of the U.S. Department of Agriculture’s Center for Nutrition Policy and Promotion. Findings that “have less support are put on the list of things to do with regard to more research.” Right now, Post explains, the agency’s main message to Americans is to limit overall calorie intake, irrespective of the source. “We’re finding that messages to consumers need to be short and simple and to the point,” he says. Another issue facing regulatory agencies, notes Harvard’s Stampfer, is that “the sugared beverage industry is lobbying very hard and trying to cast doubt on all these studies.”
    and also:

    “If you reduce saturated fat and replace it with high glycemic-index carbohydrates, you may not only not get benefits—you might actually produce harm,” Ludwig argues. The next time you eat a piece of buttered toast, he says, consider that “butter is actually the more healthful component.”

  • #2
    Thanks for that link! I just sent it to my dad who's been wanting more information on saturated fat being good/processed carbs being bad, so hopefully he'll like it.
    You are what you eat,
    and what you eat eats too - Michael Pollan


    • #3
      “If you reduce saturated fat and replace it with high glycemic-index carbohydrates, you may not only not get benefits—you might actually produce harm,” Ludwig argues. The next time you eat a piece of buttered toast, he says, consider that “butter is actually the more healthful component.”
      Thus, the simple brilliance of Taubes' book cover. Brilliant.


      • #4
        I'm going to read the meta-analysis by Krauss. It should be interesting.
        A steak a day keeps the doctor away


        • #5
          This is very encouraging!


          • #6
            Excellent article. I just sent it to my father who needs to learn A LOT... I am working on it and am succeeding...
            Find me at Cheers!


            • #7
              Great link, thanks!
              Rangers Lead the Way, Hooah!


              • #8
                EDIT: Siri-Tarino, Sun Q, Hu F B, Krauss, R M. "Meta-Analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease", American Journal of Clinical Nutrition 2010, vol. 91, pp535-546

                So I finally read the meta analysis by Krauss and it is a very informative and detailed meta-analysis of previous studies that looked at the link between saturated fat and heart disease.

                They found 21 studies that fitted their criteria. 16 of these studies examined the link between coronary heart disease and saturated fat 8 of them examined the link between cardio vascular disease (including CHD) and saturated fat. All combined this study included the data for 347,747 participants. One of the papers falls into both the CHD and CVD category because of how it was designed.

                The paper found no link between saturated fat intake and CVD, CHD or stroke.

                They also performed a secondary meta-analysis that looked at the effects of replacing staurated fat with polyunsaturated fat or carbs. 5 studies dealt with PUFA and 6 with carb.

                Of the studies 12 were conducted in North America, 6 in Europe, 2 in Japan and 1 in Israel.

                The reviewed papers that found a link between sat fat and CVD were the Lipid Research Clinics Study, Health Professionals Follow Up Study, Health and Lifestyle Survey, Strong Heart Study, and studies by Mann et al and Jakobsen et al. Mann et al's study does not control for any other dietry intakes and I consider that a poor study design which allows way too many confounding factors. Some other studies didn't control for diet either and I consider them useless.

                Other studies control for varying things in diet including vegetables, fruit, carb intake, PUFA etc and some studies broke Cholestrol down into HDL, LDL and trig but not all did.

                There is a table in the paper that nicely sets out all this data and I am not going to copy it all. My point, and this is very important, is that many studies are of a poor design and do not control for many confounding variables that will fuck up your results. So always treat any scientific study skeptically, especially in something like nutrition where most people think everything that is not sat fat is created equal.

                The Strong Heart study when adjusted for TRANS fats found no link between sat fat and CVD. So their conclusion is bullshit because they didn't look at the effect trans fats may have on the outcome and when trans fat consumption is taken into account sat fat is found to be not guilty.

                Two other studies I've not mentioned found an inverse relationship between sat fat and hemorrhagic stroke which seems like good news for us. The studies, in case anyone is interested:

                Gillman MW, Cupples LA, Millen BE, Ellison RC, Wolf PA, "Inverse association of Dietary fat with development of ischemic stroke in men." Journal of the America Medical Association 1997, vol. 278, pp2145-2150. AKA: The Framingham Study

                Iso H, Sato S, Kitamura A, Naito Y, Shimamoto T, Komachi Y. "Fat and Protein intakes of and risk of intraparenchymal hemorrhage among middle aged Japanese." American Journal of Epidemiology 2003, vol. 157, pp32-39.

                I did a quick google search and apparently only 17% of strokes are hemorrhagic:

                Excluding those two studies since hemorrahgic stroke is only one type of stroke and pooling the estimates to get a risk ratio they found no relationship between stroke, CVD and CHD.

                Subgroup analyses found no link between CVD and age or sex compared to sat fat intake, though this finding is not as strong since not all the studies they reviewed differentiated between sex or age.

                They also conducted a test to determine publication bias and found that publication favoured those studies that reported a link between sat fat and heart disease over those that didn't.

                Other things to note: Not all studies adjusted for total energy intake and some that did adjust for it didn't include carb intake or make a distinction between the type of fats yet total energy "has been shown to be relevant in evaluating nutriet-disease relations". For more on this rather obvious factor that many studies leave out the authors referred to:

                Willett WC, Howe GR, Kushi LR, "Adjustment for total energy intake in epidemiologic studies." America Journal of Clinical Nutrition 1997, vol. 65 (supplement) pp 1220 S - 1228 S & discussion 1229S - 31S.

                Two more caveats: People (particularly overweight people) often under report the number of total calories they eat and this throws of findings and secondly asking participants to recall what they ate in the previous 24 hours is easy but not a very good illustration of their diet. In fact there is no really reliable way to get the facts on someone's diet when relying on their self reporting.

                Also inverse risks of PUFA and CHD have been reported in other papers. Replacing 5% of sat fat intake with PUFA reduces CHD by 42%.

                See: Laaksonen DE, Nyyssonen K, Niskanen L, Rissanen TH, Salonen JT. "Prediction of cardiovascular mortality in middle aged men by dietary and serum linoleic and polyunsaturated fatty acids." Archives of Internal Medicine 2005, vol. 165, pp193-199.

                Sonio M, Lassko M, Lehto S, Hakala P, Ronnemaa T. "Dietary fat predicts coronary heart disease events in subjects with type 2 diabetes." Diabetes Care 2003, vol. 26, pp619-624

                Hu FB, Stampfer MJ, Manson JE, et al. "Dietary fat intake and the riks of coronary heart disease in women." New England Journal of Medicine 1997, vol. 337, pp1411-9

                Hu FB, Stampfer MJ, Manson JE, et al. "Dietary saturated fats and their food sources in relation to the risk of coronary heart disease in women." American Journal of Clinical Nutrition 2010, vol. 70, pp 1001-8.
                Only one study in the meta-analysis included that criteria and it found no benefit to PUFA.

                The authors speculate that the presumed beneficial affects on reducing CHD by reducing sat fat intake may actually be due to the increases in PUFA instead.

                The exclusion of the two Japanese studies (since Japan has lower sat fat intakes) did not change things. There was still no link between sat fat intake and heart disease.

                The studies they examined were not good enough for them to conduct a meta analysis on whether replacing sat fat with PUFA or carb has any beneficial effect on CVD risk.

                In Summary: This is a very good meta-analysis which finds no link between sat fat intake and cardiovascular disease or coronary heart disease. Studies that found a link have poor study design and poor statistical methods.

                This is a very instructive paper, not only because it deals thoroughly with an important topic, but because it is straight forward and easy to follow and highlights the difference between poor research and good research. If you know a little statistics then this paper will not be too hard to read and if you have no statistical background you can probably get everything they are talking about with a little effort.

                So always remember to take any scientific report with a grain of salt unless you can be sure of the validity of the study's design and method.
                Last edited by Bushrat; 05-20-2010, 04:56 PM.
                A steak a day keeps the doctor away