Quiet Heather wrote:I keep hearing from some people who disagree with eating a very low fat diet like this one that there is NO evidence that saturated fat is bad for you. They say that there have been NO studies that have looked only at natural saturated fat, and that EVERY study that implicated saturated fat lumped unnatural trans fats in with natural saturated fat, and so it was the trans fats that were the real culprit, not the saturated fat.
I have a hard time believing this - it's the insistence that "every" study was done this way that I'm finding hard to believe. Also, I've read that meat and dairy products have naturally occurring trans fats. Are these as harmful as the ones you get from eating hydrogenated oils? Do you know of any studies that look specifically at the health risks of natural saturated fat?
Thanks!
Hi Heather
I have a hard time believing it also, especially since there is so much data to support the harm of saturated fat.
It is very easy for them to do controlled studies and replace one single item, and they have done that many items not only in humans, but also in monkeys.
Here are notes from a conversation with Dr Castelli, the former director of the Framingham Heart Study. Some quotes of his are often used to promote that saturated fat is not harmful but they are "mis" quotes.
So, in order to figure out whether it was eating saturated fats that
was lowering cholesterol, or the exercise instead, they investigated
further. Specifically, a direct quote cut-and-pasted from Dr.
Castelli's communication:
".... how do you know that eating cholesterol and saturated fat raise
your serum cholesterol? You have to do a metabolic ward study. Being
on a metabolic ward is like being in prison and the two best studies
were done in Minneapolis (Dr. Ancel Keys) and Boston (Mark Hegsted).
They would increase the cholesterol and saturated fat in your diet,
controlling for everything else and showed the more cholesterol you
ate, or the more saturated fat you ate, the higher you serum
cholesterol went."
Further, he goes on:
"Virtually all the early diet trials were based on removing saturated
fat and cholesterol from you diet and lowering your serum
cholesterol. They also showed that the better they did this, the
better was the fall in coronary heart disease."
So, Dr. Castelli is saying, not only did lowering saturated fat
intake drop cholesterol, it also reduced heart disease. And further,
Dr. Castelli says:
"....... the latest diet data from Framingham showed that the women of
Framingham who ate a high fat, low calorie diet doubled the deposits
in their carotid arteries compared to women on a heart healthy diet."
And still further he notes that the impact on lipids of a high
saturated fat diet is even greater than that measured by standard
cholesterol tests. This is because the tests are normally done after
an eight to ten hour fast. But the atherogenic effects (chylomicron
remnants) peak around the time the meal is eaten and then diminish
dramatically as the hours go by. So they are much greater in the
period immediately following a high fat meal than when the tested
blood is normally drawn many hours later.
They not only controlled for other fats, they also controlled for dietary cholesterol.
Am J Clin Nutr. 1976 Nov;29(11):1184-9 Independence of the effects of cholesterol and degree of saturation of the fat in the diet on serum cholesterol in man.
Substitution of the saturated diet for the polyunsatured diet caused a significant elevation of serum cholesterol which was the same when the substitution was made in the presence or in the absence of added dietary cholesterol.
They have also done studies in Green Monkeys, controlling for everything and only changing the type of fat in their diet and again, the high saturated fat diets cause atherosclerosis. And, substituting out the saturated fat, lowers their risk and the development of atherosclerosis.
Dietary polyunsaturated fat decreases coronary artery atherosclerosis in a pediatric-aged population of African green monkeys. Arterioscler-Thromb. 1994 Apr; 14(4): 587-97
Rudel LL, Parks JS, Sawyer JK. Compared with dietary monounsaturated and saturated fat, polyunsaturated fat protects African green monkeys from coronary artery atherosclerosis. Arterioscler Thromb Vasc Biol. 1995 Dec;15(12):2101–2110.
Rudel LL, Haines JL, Sawyer JK. Effects on plasma lipoproteins of monounsaturated, saturated, and polyunsaturated fatty acids in the diet of African green monkeys. J Lipid Res. 1990 Oct;31(10):1873–1882.
Mattson FH, Grundy SM. Comparison of effects of dietary saturated, monounsaturated, and polyunsaturated fatty acids on plasma lipids and lipoproteins in man. J Lipid Res. 1985 Feb;26(2):194–202
In Health
Jeff
