Nutrition and Heart Health

The Physicians Committee
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Nutrition and Heart Health

A modified diet, particularly if combined with regular exercise, can prevent, delay, or even reverse the progression of atherosclerosis and development of coronary artery disease, and reduce the risk for heart attack.

Decreasing intake of saturated fat and cholesterol lowers blood cholesterol levels.
Saturated fats and cholesterol in the diet increase levels of cholesterol in the blood, particularly low density lipoprotein (LDL, or “bad”) cholesterol. Following a diet low in saturated fat and cholesterol can help reduce atherosclerosis.

The National Cholesterol Education Program has recommended moderate reductions in total fat (≤ 30 percent of calories), saturated fat (≤ 7 percent of calories), and cholesterol (< 200 mg/day) intake. In clinical trials, such changes reduce LDL cholesterol concentration by about 5 percent. Studies suggest that low–fat vegetarian and vegan regimens are significantly more effective, reducing LDL cholesterol approximately 15 to 30 percent. Because such regimens have also been shown to reduce body weight and blood pressure, and to reverse atherosclerosis, they provide much more clinical benefit. From the patient’s standpoint, they are often preferred, provided that individuals receive basic diet instruction.

Increasing dietary fiber can reduce blood cholesterol.
Soluble fiber, which is found in oats, barley, and beans, is particularly helpful for reducing cholesterol in the blood. Sources of soluble dietary fiber and pectin, found mainly in fruits and vegetables, have also been shown to reduce the progression of atherosclerosis.

Soy products can reduce cholesterol.
Both population–based and clinical studies have shown that soy products (e.g., soymilk and meat substitutes) may reduce CHD risk. In addition to reducing total cholesterol, soy has cardioprotective effects, such as lowering LDL and blood pressure.

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

Increasing intake of antioxidants can improve functioning of the blood vessels.
Dietary antioxidants, folate, magnesium, and other substances in foods may improve the functioning of blood vessels and may also reduce blood pressure.

Fruits and vegetables can help reduce the risk for CHD.
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 and very little saturated fat, and their high fiber content. Other heart protective components in fruits and vegetables include 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 that lower blood levels of carotenoids are associated with a higher risk for CHD.

Dietary intake can reduce inflammation in the blood vessels.
Inflammation plays a large role in the process of atherosclerosis. There are several ways to decrease inflammation, including weight loss, reduced intake of saturated fat (which is primarily found in animal products), reduction of partially hydrogenated vegetable oils (known as trans fats), and increasing omega–3 fat intake from healthy sources (e.g., walnuts, flax seeds, flaxseed oil, and canola oil).

Some studies have looked at the addition of omega–3 fatty acids in either foods or supplements. Several researchers have found that these fats can decrease inflammation and atherosclerosis. In addition, they have other heart protective properties, including “thinning” the blood and reducing the risk for arrhythmias.

However, fats or oils that provide omega–3 fatty acids do contain as many calories as other fats and are mixtures of various fat types. Fish oils, for example, include significant amounts of saturated fat (15 to 30 percent of total fat content) and cholesterol. People who include fatty fish in their diets as a means of increasing omega–3 intake will also increase total and saturated fat intake, and may experience elevated cholesterol and weight gain. Moreover, fish are often contaminated with dangerous pollutants such as mercury.

Whole grains are associated with lower risk for heart disease.
In epidemiological studies, whole grain consumption is associated with a lower risk of heart disease, as is frequent consumption of nuts. In addition to providing the lipid–lowering benefit of dietary fiber, these foods provide magnesium and vitamin E, both of which may be related to a lower risk for coronary heart disease. Nuts are high in fat and calories, however, and may influence body weight.

Alcohol consumption should not be used as a means of preventing heart disease.
Although alcohol is often said to be protective for heart disease, no controlled clinical trials have examined the effect of alcohol intake on cardiovascular endpoints. Regular alcohol consumption also contributes to several medical conditions, including serious diseases of the liver, pancreas, central nervous system, and cardiovascular system. Alcohol also increases the risks for some cancers, notably gastrointestinal and breast cancers.