Dietary recommendations to prevent coronary heart disease.

The evidence that limiting dietary saturated fat and cholesterol will lower LDL cholesterol and contribute to the reduction in risk of cardiovascular disease is adequate for sound dietary recommendations to patients and to the public at large. Reduction of intake of all saturated fats to less than 10% of calories is a practical and achievable goal for Western man. Further reduction to less than 7% of calories is possible with a motivated and well instructed patient. The mechanism by which saturated fatty acids, particularly palmitate and laurate raise LDL cholesterol need detailed biochemical and physiologic study. Dietary cholesterol is unnecessary and clearly contributes to vascular disease in Western man. This vascular effect appears to be only partially explained by its effect on LDL cholesterol. Reduction to less than 300 mg per day for men of average size is achievable. Women and those eating fewer calories should strive for even less. Monounsaturated fats (oleic acid) can be consumed at levels of 20% of calories without significant concern if total calories are within limits to maintain desirable weight. Omega-6 polyunsaturated fats do not offer a significant health concern and need not be limited below the current intake of 7% of calories in the United States. Populations eating higher levels should be monitored to determine if such intakes are associated with either improved health or long-term ill effects since this level of intake has not been a long-standing tradition in any known culture. Omega-3 fatty acids might be increased to 2 or 3% of calories with potential benefit. Eating fish and marine animals is the most clearly documented safe method for achieving this. Larger intakes and particularly the use of fish oil supplements is unproven therapy for vascular disease prevention and needs much further study as a medical treatment for a variety of disorders. Protein intake is more than adequate in the USA and further increases could have negative effects on the prevalence of renal disease and osteoporosis. Although these issues are of hypothetical interest at the moment, they are worthy of considerable investigation. Complex carbohydrates consumed as components of vegetables, fruits and grains should be considered proven safe and healthful. Increasing calories from these sources at the expense of saturated fats and simple sugars should prove highly beneficial to Western populations. Fiber from these sources may have beneficial effects on blood cholesterol and intestinal function. Soluble fiber is documented to lower LDL cholesterol but the mechanism of this effect is not established and is worthy of considerable study.(ABSTRACT TRUNCATED AT 400 WORDS)