In the land of plenty, many Americans have grown accustomed to eating far too much fatty food. But it's become increasingly difficult to ignore the warnings of health professionals: a high-fat diet can lead to disaster, in the form of hardening of the arteries, a stroke, or a heart attack.

For heart health, nutrition experts now recommend that people eat a diet low in cholesterol and saturated fat, with less than 30 percent of total calories coming from fat. In addition to exercise and weight control, several dietary measures have been added to the preventive arsenal for the war against heart disease.

Current research suggests that your risk of heart disease may increase if you are deficient in certain vitamins. Along with others, vitamin E, vitamin C, and folate help protect your arteries from attacks by free radicals and other reactive molecules. If these vitamins are not present in sufficient amounts, highly charged oxygen can turn cholesterol into oxidized cholesterol. Studies show that oxidized cholesterol is very toxic to arterial walls and may promote the rapid buildup of a fatty material called plaque. This plaque may rupture or completely block a coronary artery, resulting in a heart attack.

Antioxidant vitamins

Vitamin E

As an antioxidant, vitamin E may help reduce your risk of heart disease in several ways. First, it shields your arteries from the damaging effects of free radicals. The vitamin also seems to help prevent the formation of blood clots that may trigger a heart attack. In a controlled trial of patients with heart disease, there was a 77 percent reduced incidence of nonfatal heart attacks among patients who took vitamin E for more than a year. The vitamin did not significantly reduce overall deaths, however.

Based on current evidence, experts recommend that people with heart disease consume 400 international units (IU) of vitamin E daily. Food sources include vegetable oils, seeds, nuts, brown rice, and wheat germ. Be sure to consult with your health care provider before taking supplements -- especially if you're taking blood thinners or blood-pressure pills, which may interact with vitamin E and cause bleeding problems.

Vitamin C

Preliminary data show that vitamin C, another antioxidant, seems to work with vitamin E to prevent blocked arteries. One study following 11,349 American men and women over ten years found that those with the highest intake of vitamin C had the lowest rate of heart disease. The best sources are fresh citrus, broccoli, strawberries, and tomatoes. Up to 1 gram of vitamin C a day is recommended.

B-complex vitamins

Vitamin B-6, vitamin B-12, and folate are involved in the metabolism of homocysteine, a product of the breakdown of certain proteins. A deficiency of these B vitamins may lead to the toxic accumulation of homocysteine. Excess levels can damage artery walls, causing plaque formation, blood clots, and a buildup of oxidized cholesterol.

Scientists are studying whether homocysteine reduction helps prevent heart disease. In the meantime, the American Heart Association recommends lowering your levels by consuming adequate amounts of B vitamins -- especially folate. When choosing food sources, think foliage -- leafy greens such as spinach, kale, broccoli, and asparagus are high in folate. The vitamin is also plentiful in yellow fruits and vegetables -- such as yams, citrus, and cantaloupe -- as well as in legumes, wheat germ, and whole grains. In addition, all grain and cereal products are now fortified with folate to help prevent neural-tube birth defects.

For heart health, experts recommend consuming 400 micrograms of folate daily. Don't take B-vitamin supplements without your provider's approval, however. Folate may mask nerve disease caused by B-12 deficiency (called pernicious anemia).

In Part II Dr. Smoots will discuss more dietary discoveries for a healthier heart, including soy, seafood, phytochemicals, fiber, and garlic.

Elizabeth Smoots, M.D., F.A.A.F.P., is a board-certified family physician in Seattle, Washington. A fellow of the American Academy of Family Physicians, Dr. Smoots specializes in prevention and primary care medicine.