Report: No Need For Antioxidant Pills

In a big blow to the dietary supplement industry, a new report by a National Academy of Sciences research panel finds that Americans can get all the antioxidants they need to stay healthy from food, reports CBS Medical Correspondent Elizabeth Kaledin.

Saying there can be too much of a good thing, for the first time ever Academy researchers are setting guidelines for maximum recommended amounts of antioxidants like vitamins C and E and selenium.

Dr. Norman Krinsky, chairman of the vitamin panel, says, "It is possible to achieve the RDAs (Recommended Dietary Allowances) by diet alone."

Antioxidants are compounds known to have disease fighting properties, but the report, released Tuesday by the Institute of Medicine, finds no evidence that mega-doses make any difference.

That means the fistful of vitamin C you swallow to fight a cold is going to waste.

Krinsky says, "High doses of C may shorten the duration of the symptoms of a cold, but certainly not prevent it."

While supplements may not be necessary, the report does suggest changes in current federal guidelines.

Women should consume 75 milligrams of vitamin C each day, and men should consume 90 milligrams, both up from 60 milligrams, the report said.

Smokers, who are more likely to suffer from damaged cells and depleted vitamin C, need an additional 35 milligrams daily.

The researchers said these levels can easily be met without taking supplements, and people can get vitamin C by eating citrus fruits, potatoes, strawberries, broccoli and leafy green vegetables. An 8-ounce glass of orange juice provides about 100 milligrams of vitamin C.

Any amount of the vitamin above the RDA is likely to be excreted by the body unused, Krinsky said.

For vitamin E, both women and men should consume 15 milligrams or 22 International Units, or I.U., each day from foods such as vegetable oil, nuts, seeds and liver. The vitamin E consumed should be "alpha-tocopherol," the only type that human blood can maintain and transfer to cells when needed.

Women and men should also get 55 micrograms of the nutrient selenium each day from foods including seafood, liver, meat, and grains, according to the recommendation.

Nutritionists like Barbara Levine say a well-balanced diet will easily hit those targets, and then some.

She says, "Fruits and vegetables and grains have a whole variety of vitamins and minerals and other phyto -- meaning plant -- chemicals that are protective for heart disease, for cancer."

Most North America adults already get enough of these three nutrients in their diets and those who don't can meet the new recommendations simply by eating more fruits and vegetables, Krinsky says.

Antioxidants are substances that cleanse the body of damaging oxygen molecules known as "free radicals," which are suspected of triggering diseases. Many people routinely take high doses of vitamin C and other antioxidants in the beief that they will prevent or cure everything from the common cold to cancer.

Krinsky warns people not to go overboard.

He says "An upper level of 2,000 milligrams -- that is 2 grams -- of vitamin C can cause unpleasant side effects. The most common one would be diarrhea."

The upper level for vitamin E, based only on vitamin supplements, is 1,000 milligrams. That's roughly equivalent to 1,500 I.U. of "d-alpha-tocopherol," sometimes labeled as "natural source" vitamin E. People consuming more than the upper limit face a greater risk of stroke and uncontrolled bleeding.

The maximum intake level for selenium from both food and supplements is 400 micrograms daily. More than this amount could cause selenosis, a toxic reaction marked by hair loss and brittle nails.

For busy Americans worried about getting three square meals, a multi-vitamin will do no harm, but the bottom line of this report is, the best way to stay well is to eat well.

Too few studies have tested the effects of dietary antioxidants in people, and some of the testing that has been done has produced unclear results, the vitamin panel researchers say.

Krinsky says, "Although a large number of population studies reveal a link between a diet rich in foods containing antioxidants, such as fruits and vegetables, and a lower incidence of certain chronic diseases, we cannot conclude at this time that the antioxidants are the reason." He says other nutrients or factors could be causing the results.

The Institute of Medicine, a private, nonprofit organization that advises the federal government, is part of the National Academy of Sciences, which has set the nation's Recommended Dietary Allowances for nutrients since 1941.