The role of diet in coronary heart disease is evident from its pathological process, which involves the formation of arterial plaques, alterations in endothelial function (which, in turn, influence blood pressure), heightened risk for thrombosis, and inflammatory processes. Diet plays a role through the regulation of blood lipids and by influencing endothelial function and the underlying inflammation that causes disease progression. A modified diet, particularly if combined with regular exercise, can prevent, delay, or reverse the progression of atherosclerosis and development of CHD, with subsequent reduction in cardiovascular events.

The primary goals of dietary intervention are described below.

Controlling Blood Lipid Concentrations

Saturated fats and cholesterol in the diet increase levels of blood lipids, particularly LDL cholesterol, while soluble fiber tends to reduce them. Controlling blood lipoprotein concentrations with a combination of diet, exercise, and medication, if necessary, is a cornerstone of treatment for most CHD patients, as described in more detail in the Hyperlipidemia chapter.

Decreasing dietary saturated fat and cholesterol. Following diets low in saturated fat and cholesterol can help reduce progression of atherosclerosis.The National Cholesterol Education Program has recommended moderate reductions in total fat (≤ 30% of energy), saturated fat (≤ 7% of energy), and cholesterol (< 200 mg/day) intake. In clinical trials, such changes reduce plasma LDL cholesterol concentration about 5%.Studies suggest that low–fat vegetarian and vegan regimens are significantly more effective, reducing LDL cholesterol approximately 15% to 30%.15–16 Because such regimens have also been shown to reduce body weight and blood pressure and to be useful in programs for reversing atherosclerosis, they may be preferable to many patients, provided they are prescribed along with basic diet instruction.

Increasing dietary fiber. Soluble fiber, as is found in oats, barley, and beans, is particularly helpful in this regard. (See Hyperlipidemia for more information.)Sources of soluble dietary fiber and pectin, found mainly in fruits and vegetables, have also reduced atherosclerotic progression.

Consuming soy products. Both epidemiologic and clinical studies have shown that soy foods (eg, soymilk and meat substitutes) may reduce CHD risk. In addition to reducing blood lipids, soy has cardioprotective effects, such as lowering oxidized LDL, homocysteine, and blood pressure.

Clinical trials have combined these lipid–lowering strategies. A vegetarian diet emphasizing cholesterol–lowering foods (including oats, soy foods, nuts, and sterol/stanol margarines) appears to be particularly effective, lowering LDL cholesterol concentration approximately 30%, an effect similar to that of treatment with lovastatin.

Improving Antioxidant Status and Endothelial Function

Dietary antioxidants, folate, magnesium, and other substances in foods may reduce the burden of oxidized LDL and improve endothelial function through increased availability of nitric oxide. Diet–related improvements in endothelial function may also reduce blood pressure.

Fruits and vegetables can help reduce atherosclerosis and lower risk for CHD, particularly if the diet is low in saturated fat. However, the benefits of these foods go beyond their having no cholesterol, very little saturated fat, and abundant fiber. Among their cardioactive components are vitamin C, antioxidant flavonoids, and folic acid.

Several studies have shown that higher dietary intakes of carotenoid–containing fruits and vegetables are associated with a decreased risk of coronary artery disease. Others have found an inverse relationship between lower blood levels of