Diet Can Have Worthwhile Effects on Human Plasma Cholesterol
The first well designed experiments, feeding cholesterol to humans, by Keys (reported around 1952) showed surprisingly little effect on serum cholesterol, but total dietary fat did raise serum cholesterol. Next, from around 1956 it was found that effects differed with the predominant fatty acids in the dietary fat. When saturated fatty acids dominated, serum cholesterol was increased, while polyunsaturated fats tended to lower serum cholesterol. It was LDL- or β-lipoprotein cholesterol that was increased or decreased by the fatty acid pattern. Further work showed the different effects of individual saturated and unsaturated fatty acids. Cholesterol balance experiments are complicated because of plant sterols in the diet but it appeared that different fatty acids do not change serum cholesterol by altering cholesterol excretion. They probably affect activity of the LDL-receptor in cell membranes (discovered by Brown and Goldstein ). Years 1952–1965.