Effect of unsaturated fats and cholesterol on serum and fecal lipids. A study of healthy middle-aged men.

Modification of the Western diet, with an intake of 2,500 kcal per day and a decrease in cholesterol and fat intake to 33 per cent of calories with a P:S of 0.40, failed to alter serum lipids significantly. Evidence suggested that increasing the daily intake of cholesterol resulted in deposition in the body tissues. However, when the fatty acid composition and the P:S ratio of dietary fat were adjusted, lower serum lipids and a compensatory increase in fecal sterols occurred when cholesterol was added to the diet. Changes in serum lipoproteins in the subjects fed a "prudent" or a common diet indicate an increase in the proportion of HDL-cholesterol which may be beneficial in reducing coronary heart disease. Evidence suggests that, in absence of caloric excess, lowering of serum lipids and increased removal of fecal sterols is possible on a prudent diet without major modification of the customary foods, but that a high P:S ratio is required.