Peter Ardito/Fitness MagazineBy the editors of FITNESS Magazine
Should you take Vitamin E? What's the best source of Vitamin C? What are flavonoids anyway? We've got the answers.
Good or Bad?
Amazing. Miraculous. Lifesaving. Until recently, these were just some of the superlatives used to describe the disease-fighting compounds called antioxidants. And health-food-store hucksters weren't the only ones spouting them either. Top scientists at Harvard, Penn State, Tufts and other institutions issued a slew of studies showing that antioxidants could work wonders by neutralizing free radicals-wayward oxygen-carrying molecules that damage cells, leading to cancer, heart disease, memory loss, even wrinkles. Soon it seemed like everyone from your internist to your Aunt Tillie was popping vitamin E pills and drinking gallons of green tea. Then the reports turned unfavorable, even scary. One study showed that vitamin E supplements, once touted as a potent weapon against heart disease, had no benefit. Another trial designed to test the anticancer potential of beta-carotene found that high-dose pills actually raised lung cancer risk in certain people.
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Research showing that vitamin C can damage cells' DNA has received a lot of attention, but these studies were done in test tubes, not people. Most experts say vitamin C is safe in moderate doses. And many people appear to be skimping on C. Experts say 20 to 30 percent of Americans may have low levels in their blood and up to 16 percent may be deficient. In a British study done last year, men and women with high blood levels of C had about half the risk of dying from heart disease, cancer and other ailments than those with low levels. In addition, C protects against cataracts. In a 14-year study of 478 women, Tufts University researchers found that those who took vitamin C supplements reduced their risk of developing cataracts by a third.
Whether vitamin E can prevent heart disease is still an open question. Studies show that taking supplements didn't help people who already had heart problems, but many researchers think the vitamin may be protective if you start taking it early, before arteries become clogged with cholesterol. Both the Nurses' Health Study and the Iowa Women's Health Study-two large investigations focusing specifically on women-found that vitamin E pills cut heart disease risk nearly in half. But heart disease isn't the only reason to be concerned about your E intake. "When people ask me what they can do to keep their brains healthy, I say take vitamin E," says Jeff Victoroff, M.D., a neurologist at the University of Southern California and author of Saving Your Brain (Bantam, 2002). It improves blood flow to the brain and may protect against Alzheimer's disease. Vitamin E may help ward off colon cancer as well. According to a study at Fred Hutchison Cancer Research Center in Seattle, people who take vitamin E cut their risk in half. The Iowa Women's Health Study found that women with the highest E intake lowered their odds of colon cancer by almost 70 percent.
Daily Dose: You can meet your nutritional needs with 22 international units (or 15 mg) a day. But to get E's disease-fighting benefits, many experts think you need 400 to 600 IU a day.
Food or Supplements? Vitamin E is found mostly in foods high in polyunsaturated fats, like vegetable oils, nuts and margarine, but you need a supplement to reach the 400 to 600 IU level. Dr. Victoroff says the best choice is natural.
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Red wine, purple grape juice, tea (black and green), apples, herbs (like oregano and parsley), raisins, prunes, berries, chocolate, even beer are all brimming with flavonoids-a term used for a family of antioxidants that may be even more potent than vitamin C or E. For example, the combination of flavonoid compounds in oregano packs 12 times the antioxi-dant punch of oranges, according to a study from the USDA. Two recent studies found that flavonoids in apples, tea and chocolate can protect against heart disease. Those in tea, called catechins, are also believed to fight cancer and prevent bone loss that leads to osteo-porosis. Polyphenols, another type of flavonoid found in red wine, helps keep blood vessels open, ensuring adequate blood flow to the heart.
Daily Dose: Experts haven't yet set a recommended level; estimates range from 100 to 500 mg a day. A cup of tea contains about 170 mg.
Food or Supplements? So far only a handful of the 4,000 flavonoids known to exist in fruits and vegetables have been singled out as possible disease fighters. But research in this area is just beginning, and it may turn out that some of these other flavonoids are important. That's why experts say you should rely on foods to ensure that you're getting a broad spectrum. Although supplements on the market may provide 1,000 mg of flavonoids per pill, they're likely to contain just a few types. Also, research at the University of California at Berkeley suggests that, at this high level, flavonoids can damage cells instead of protect them. These compounds are flushed out of the body quickly, so try to eat flavonoid-rich foods several times throughout the day. Some experts think the reason heart disease and cancer rates are so low in parts of Asia is simply because people there drink tea with every meal.
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.
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.
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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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Peter Ardito/Fitness MagazineBy the editors of FITNESS Magazine