Unresolved problems in the diet-heart issue.

A n enigma for the 1980s is the continuing diet- heart controversy. Over 60 years ago, the cholesterol-fed rabbit model of atherosclerosis was discovered, and coronary atherosclerosis was linked to the clinical syndrome of myocardial infarction. Over 30 years ago, the role of dietary fat in the etiology of atherosclerotic disease was suggested, and epidemiologic evidence linking diet to atherosclerotic disease began to accumulate. The number of scientific papers on diet and atherosclerosis is now enormous. On the one hand, believers assemble these reports into an argument for dietary cholesterol and saturated fat being major causative agents for the high levels of atherosclerosis in the technically developed countries. On the other hand, skeptics contend that inconsistencies, gaps, and paradoxes in the evidence do not permit one to infer a causative relationship between these dietary components and atherosclerosis. When conservative interpretations of the diet-heart issue 1 are contrasted with recommendations such as those of the American Heart Association, 2 it is no wonder that the public is confused.