Wednesday, May 26, 2010

WHS - Dietary Cholesterol a Mythical Beast

There are still some badly written articles which report that consumption of cholesterol has an impact on the consumer's lipid profile - in other words, that eating cholesterol results in worse cholesterol levels and CVD. Here's a simple refutation, but it amazes me that something so totally unfactual has been repeated so often from so many sources over the years, by very smart, and presumably educated people. One cannot take any of the information in this arena at face value.

"The diet-heart hypothesis is the idea that (1) dietary saturated fat, and in some versions, dietary cholesterol, raise blood cholesterol in humans and (2) therefore contribute to the risk of heart attack.

I'm not going to spend a lot of time on the theory in relation to dietary cholesterol because there really isn't much evidence to debunk in humans. As far as I can tell, most diet-health researchers don't take this theory seriously anymore because the evidence has simply failed to materialize. Dr. Walter Willett doesn't believe it, and even Dr. Ancel Keys didn't believe it. Here's a graph from the Framingham Heart study (via the book Prevention of Coronary Heart Disease, by Dr. Harumi Okuyama et al.) to drive home the point. Eggs are the most concentrated source of cholesterol in the American diet. In this graph, the "low" group ate 0-2 eggs per week, the "medium" group ate 3-7, and the "high" group ate 7-14 (click for larger image): The distribution of blood cholesterol levels between the three groups was virtually identical. The study also found no association between egg consumption and heart attack risk. Dietary cholesterol does not raise serum cholesterol in the long term, because humans are adapted to eating cholesterol. We simply adjust our own cholesterol metabolism to compensate when the amount in the diet increases, like dogs. Rabbits don't have that feedback mechanism because their natural diet doesn't include cholesterol, so feeding them dietary cholesterol increases blood cholesterol and causes vascular pathology."

http://wholehealthsource.blogspot.com/search/label/Tokelau

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