Cholesterol

Some of the earliest clues about possible ill effects of cholesterol on human health came from the research of Russian biologist Nikolai Anitschow in the 1910s. Anitschow fed rabbits a diet high in cholesterol and found that the animals became particularly susceptible to circulatory disorders. Post-mortem studies of the animals found the presence of plaques (clumps) of cholesterol on their arterial walls.

Since Anitschow's original research, debate has raged over the relationship between cholesterol intake and circulatory disease, particular atherosclerosis (the blockage of coronary arteries with deposits of fatty material). Over time, it has become increasingly obvious that high serum cholesterol levels do have some association with such diseases. A particularly powerful study in forming this conclusion has been the on-going Framingham Study, conducted since 1948 by the National Heart Institute in the Massachusetts town that has given its name to the research. Among the recommendations evolving out of that study has been that a reduced intake of cholesterol in one's daily diet is one factor in reducing the risk of heart disease.

The cholesterol-heart disease puzzle is not completely solved. One of the remaining issues concerns the role of lipoproteins in the equation. Since cholesterol is not soluble in water, it is transported through the blood stream bound to molecules containing both fat and protein components, lipoproteins. These lipoproteins are of two kinds, high density lipoproteins (HDLs) and low density lipoproteins (LDLs). For some time, researchers have thought that LDL is particularly rich in cholesterol and, therefore, "bad," while HDL is low in cholesterol and, therefore, "good." While this analysis may be another step in the right direction, it still does not provide the final word on the role of cholesterol in the development of circulatory diseases.