Antioxidants seem to be in everything these days. Just walk down the aisle in your local grocery store, and you’ll see the shelves lined with products boasting they contain antioxidants.
But how safe are they? Should we be loading up on them? Are antioxidants the same as vitamins?
Antioxidants are substances that may protect your cells against the effects of free radicals, according to McKay-Dee Hospital registered dietitian Grant Cefalo. Free radicals are molecules produced when your body breaks down food, or by environmental exposures like tobacco smoke and radiation.
Free radicals can damage cells, and may play a role in heart disease, cancer and other diseases. Well-known antioxidants include vitamins A, C and E; beta-carotene; selenium; lycopene and lutein.
According to Consumer Reports on Health, there are thousands of antioxidants, but only a few of them are vitamins. Some are minerals; others are enzymes. Foods rich in antioxidants include fruit, vegetables, whole grains, tea, chocolate and red wine.
“Technically, they’re substances that prevent oxidation. A cut apple that browns is an example of oxidation,” said Jennifer James, an outpatient dietitian at Ogden Regional Medical Center. “Aging, cancer, heart disease, Alzheimer’s, cataracts are all thought to be caused in part by free radicals that are not neutralized. The antioxidants neutralize these free radicals.”
Our bodies also make some antioxidants, James said.
More is not better?
Some research shows that taking large amounts of antioxidant supplements can actually be harmful.
“A very famous study out of Finland that studied smokers who took beta-carotene found that those who took large amounts of antioxidants actually developed more lung cancer,” James said. “A similar study funded by the National Cancer Institute yielded similar results with smokers, former smokers and those exposed to asbestos. There’s still a lot we don’t know.”
The National Center for Complementary and Alternative Medicine warns that high-dose antioxidant supplements can also interact with certain medications. For example, vitamin E supplements may increase the risk of bleeding in people who are taking blood thinners.
High use of vitamin E supplements have also been linked to increased risks of hemorrhagic stroke and prostate cancer.
Good free radicals
So far, James said, no research has proved that taking antioxidant supplements reduces disease risk.
“Free radicals may have healthy purposes in our bodies, too, such as destroying bacteria or improving insulin resistance from exercise, according to some researchers,” James said. “Taking boatloads of an antioxidant may interfere with free radicals’ good aspects.”
Consumer Reports on Health also reports that antioxidant claims on packaged food don’t always mean a health benefit. Some food manufacturers add an antioxidant and then label the product as containing antioxidants in the hopes of boosting sales.
“Unfortunately, ‘antioxidant’ is a very loosely used term,” said Joy Dubost, a nutritionist for the Academy of Nutrition and Dietetics. “Outside the lab, it has become more of a marketing term than a scientific term.”
Food sources best
In addition, said McKay-Dee Hospital registered dietitian Beth Ann Smith, keep in mind that supplements are not approved by the Food and Drug Administration.
“Whole foods are always best, especially to get a mix of antioxidants, not just one specific antioxidant,” she said. “When you start isolating these compounds and take them, let’s say, in pill form, they may have the opposite effect. The strength of evidence is quite limited for supplements.”
Plus, not all antioxidants are created equal.
Different antioxidants fight different free radicals. For example, James said, vitamin C will fight free radicals in body fluids, but not in fat tissue. Vitamin E works in fat tissue. So it’s a good idea to eat a wide variety of foods to benefit from all of the antioxidants available.
Instead of amping up your intake with supplements, McKay-Dee Hospital registered dietitian Sherrie Calles said, it’s best to follow the advice of the Dietary Guidelines for Americans.
“Consume a wide variety of whole plant foods in your diet, especially fruits, vegetables, nuts, seeds and unsaturated oils,” she said. “All of the ingredients that make up this variety of foods work together to promote health. There is no question that we need to eat a higher quantity and diversity of foods that are high in antioxidants. They all contain different substances and they all contribute to good health.”