Is Too Much Vitamin C and E Good For You?

-- It's a big blow to the dietary supplement industry. The new report finds that all the antioxidants Americans need to stay healthy and meet the federal recommended daily allowance or RDA, comes from food. CBS correspondent Elizabeth Kaledin reports.

Antioxidants like vitamins C and E and selenium are compounds known to have disease-fighting properties. But the report released today by the Institute of Medicine finds no evidence that massive doses of the compounds make any difference. That means the fistful of vitamin C you swallow to fight a cold is going to waste.

"High doses of vitamin C may shorten the duration of a cold but certainly not prevent it," says Dr. Norman Krinsky at Tufts University School of Medicine in Boston.

While supplements may not be necessary, the report does suggest changes in current federal guidelines increasing recommended vitamin C intake from 60 mg a day to 75 mg for women and 90 mg for men. Vitamin E intake should be 15 mg a day.

Nutritionists like Barbara Levine at Rockefeller University in New York says a well balanced diet will easily hit those targets and then some "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."

In addition to setting new minimum daily allowances for certain antioxidants, for the first time ever, the Institute of Medicine is setting guidelines for maximum amounts recommended saying there can be too much of a good thing, even too much vitamin C can be harmful.

"An upper level of 2000 milligrams that is 2 grams of vitamin C can cause unpleasant side effects, the most common one would be diarrhea," says Krinsky.

For busy Americans worried about getting 3 square meals, a multivitamin will do no harm, but the bottom line of this report is that the best way to stay well is to eat well.