Environmental factors in coronary heart disease: diet.

The customary diet of a population is the essential factor determining susceptibility to atherosclerosis and coronary heart disease (CHD), and it does so through its effects on lipoproteins, blood pressure and the coagulation system. The simplest and possibly strongest measure of this dietary effect is the serum total cholesterol concentration in the population. Within populations on high-risk diets [high saturated fat intakes and low ratio of polyunsaturated to saturated fatty acids (P/S ratio)], hypertension and cigarette smoking are potent secondary factors. Adipose tissue fatty acid studies support this concept of a dietary basis to CHD; low levels of linoleic acid and high P/S ratios are associated with a higher risk of CHD. Marine long-chain polyunsaturated fats may play a protective role in the CHD story. Monounsaturated fats are as effective in lowering serum total cholesterol as low fat-high carbohydrate diets. Coagulation factors of possible importance to CHD risks can be affected by dietary fat intake. Dietary fats affect blood pressure levels and may initiate hypertension. Coffee and alcohol consumption do not appear to effect the risk of CHD, although coffee may raise the blood cholesterol and alcohol raise the blood pressure. Diet is probably the central environmental factor in the development of CHD.