The Truth About Antioxidants
Selenium and ArotenoidsSelenium
Selenium appears to protect against several forms of cancer, including lung and colon cancer. A 20-year Finnish study found that having high blood levels of selenium cuts lung cancer risk in half. In addition, researchers at Kings College in London and the University of Southampton showed that people with high selenium intake had half the risk of developing asthma compared to those with the lowest. Researchers aren't sure why but think that the mineral may prevent inflammation of the airways.
Daily Dose: Women need at least 55 micrograms. The cancer-protective effects seem to kick in at around 200 mcg a day. More than 400 mcg a day causes hair loss, brittle nails and possibly nerve damage. food or supplements? Stick with food. Brazil nuts, walnuts, pasta, broccoli, bran, tuna, chicken and milk are all good sources. Multivitamin/mineral pills also usually contain about 20 mcg of selenium.Arotenoids
The yellow, orange and red pigments in plant foods are collectively known as carotenoids. Beta-carotene is the most familiar, but others-alpha-carotene, lycopene, lutein and zeaxanthin-are just as important, maybe more so, when it comes to disease prevention. The Harvard Nurses’ Health Study found that carotenoids may reduce breast cancer risk. Scientists at Brigham and Women’s Hospital in Boston recently turned up evidence that high levels of carotenoids may lower the odds of ovarian cancer. Other studies have shown that lycopene protects against heart disease and that lutein and zeaxanthin fight macular degeneration, an eye disease that occurs as people grow older and is the leading cause of blindness in the U.S.
Daily Dose: Nobody knows, exactly. Most studies have looked at carotenoid intake indirectly, by measuring fruit and vegetable consumption. The Harvard study found that women who ate more than five servings a day had the lowest cancer risk. Eating plenty of raw carrots and tomatoes seemed to provide the most protection in the Brigham & Women's study. In general, researchers think that five to nine servings a day provides a good mix of carotenoids at a sufficient level to be protective.
Food or Supplements? In two large studies, beta-carotene supplements increased the risk of lung cancer in smokers. Other research shows they can also cause thickening of the lining of the carotid artery, the main blood vessel that supplies the brain. For those reasons, experts recommend getting carotenoids from foods, not supplements. (Beta-carotene from food, even at very high intakes, has never been shown to be harmful.) Fill your plate with dark green vegetables, cantaloupe, carrots, sweet potatoes, winter squash, red peppers, peaches, papaya and tomatoes.Should you give up on antioxidants?
"To take findings from a few studies and say, 'Oops-everything we thought was true isn't' would be the wrong move," says Jeffrey Blumberg, Ph.D., chief of the Antioxidants Research Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging in Boston. "In fact, we now have more evidence than ever that antioxidants offer powerful protection against a surprisingly broad range of health problems."
What has changed is the idea that you can cover all your health and nutritional needs with one or two individual antioxidant pills. "We&'re seeing that there's a lot of synergy among these compounds," says Jane Freedman, Ph.D., a researcher at Georgetown University in Washington, D.C. Getting a blend of antioxidants—more than any single substance on its own—may be the best way to protect health.
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