General conclusions

Abstract

As a nutritionist, the author would have liked to find irrefutable scientific evidence linking food habits to coronary heart disease. Such evidence would have provided hope for the prevention of ischemic heart disease even if major modification of the diet would have been necessary. Unfortunately, the large body of scientific data now available suggests that:

• (1) total blood cholesterol would seem to be only a poor indicator of the risk of developing coronary heart disease;

• (2) dietary cholesterol, in general, has little influence on blood cholesterol;

• (3) the major prevention intervention studies based on the use of hypocholesterolemic diets or drugs showed that the slight lowering of blood cholesterol levels induced by these diets and drugs had no effect on total mortality. In some instances, undesirable side-effects and a higher incidence of cancer were associated with the use of these diets and drugs. Thus, hypocholesterolemic diets high in polyunsaturated fatty acids (linoleic acid) and low in cholesterol and animal fat have little or no effect on coronary heart disease, and such diets are of little benefit in primary as well as in secondary prevention programs;

• (4) diets high in polyunsaturated fatty acids (PUFA) do not seem to increase the serum levels of HDL—a class of lipoproteins becoming known as the “good” cholesterol; and

• (5) the “lipid hypothesis,” after repeated investigation in the past two decades, remains a hypothesis for which “completely satisfactory evidence has not yet been advanced either pro or con”¹.