Vitamin E

Daily Value: 30 international units

Good Food Sources: Vegetable and nut oils, including soybean, safflower and corn; sunflower seeds; whole grains; wheat germ; spinach

Vitamin E may well prove to be one of the most powerful nutrients on the face of the earth.

Studies indicate that it fights heart disease, prevents cancer, alleviates respiratory problems and boosts your immune system's ability to fight off infectious disease. It may also prevent some of the damage that diabetes does to the body, particularly to the eyes.

How does a simple vitamin achieve such complex results? Vitamin E works in a variety of ways, but a key mechanism seen in the laboratory is its ability to neutralize free radicals, naturally occurring unstable molecules that can damage your body's healthy molecules by stealing electrons to balance themselves.

And what happens in the laboratory seems to translate into what happens in real life. Two joint studies, which looked at more than 127,000 people, for example, reported that those who took vitamin E supplements for at least two years had about 40 percent less risk of heart disease than those who didn't.

"There's a lot of evidence to support the possible benefits of vitamin E, but these are the first studies to actually measure benefits in terms of less disease and fewer heart attacks," says Meir Stampfer, M.D., Dr.P.H., an investigator at the Harvard School of Public Health who was involved with the study.

Yet despite this vitamin's ability to prevent disease, somewhere between 69 and 80 percent of older adults do not get even the Daily Value of 30 international units. And Dr. Stampfer maintains that we might need many times that amount to prevent disease.

Vitamin E deficiency, however, is very rare. Infants with low birth weight are susceptible, as are people with conditions such as cystic fibrosis, which prevents the proper absorption of fat. Signs of deficiency can include neurological and reproductive problems.

Unless you want to drink two quarts of corn oil or eat a pound of sunflower seeds every day, the only way to increase your vitamin E intake is with supplements.

There are eight different forms of the vitamin. But the supplement labeled "d-alpha-tocopherol" is the one that will give you the biggest bang for your buck. It makes more vitamin E available to your body than any other form.

d-alpha-tocopherol loses its potency when exposed to air, heat and light, so make sure it's stored in a cool, dark place. It should be taken with a meal that contains fat; otherwise your body cannot absorb it adequately. It should not be taken at the same time as an iron supplement, since iron seems to destroy vitamin E before it can get down to business.

Using Vitamin E Safely

Some studies that have found vitamin E can prevent disease have also shown that getting somewhere between 200 and 800 international units is necessary to release its power.

Fortunately, the vitamin seems to be relatively safe, even at higher doses. Studies indicate that daily supplements of 800 and 900 international units have been taken without any reported problems. People who are taking anticoagulants (sometimes called blood thinners or heart medicine) should not take vitamin E supplements, however, because they can be harmful. Some experts think it's also a good idea for people who have had strokes or bleeding problems to consult their doctors before taking supplements. Vitamin E can also interfere with the absorption and action of vitamin K, which is involved in blood coagulation.

On the other hand, those who are taking anticonvulsants, cholesterol-lowering drugs, tuberculosis drugs, ulcer medication or the antibiotic neomycin should probably talk to their doctors about increasing the amount of vitamin E they take. All of these medications can increase the body's need for the nutrient.