DEAR MAYO CLINIC:

I keep hearing that antioxidants can help prevent disease and improve my overall health. Is this true? Should I be taking antioxidant supplements each day along with my multivitamin?

ANSWER:

It is true that antioxidants -- such as vitamins C and E, carotene, lycopene, lutein and many other substances -- may play a role in helping to prevent diseases such as cancer, cardiovascular disease, Alzheimer's disease and macular degeneration.

However, research indicates that simply taking antioxidant supplements is not the best way to go about getting what your body needs. In fact, it's possible that some of these supplements could be harmful.

Fortunately, research is also increasingly showing that you can reap the potential health benefits of antioxidant intake by eating a diet rich in antioxidant-containing foods.

Antioxidants are thought to be helpful because they can neutralize free radicals, which are toxic byproducts of natural cell metabolism. Free radicals can also be introduced into the body by exposure to certain substances, such as cigarette smoke, sunlight or pesticides.

Although free radicals perform some useful immune functions, in excess or in the wrong place, they can damage healthy cells through a process called oxidation. Oxidation is thought to be a factor in the development of certain diseases. Overall, free radicals do far more harm than they do good.

Our bodies naturally produce antioxidants and are quite effective at neutralizing free radicals. The minerals copper, manganese, selenium and zinc are important players in this process. But this process isn't 100 percent effective, and its effectiveness declines with age.

One reason foods appear to be a better choice than supplements is that foods contain an unmatchable array of antioxidant substances. A supplement may contain a single type of antioxidant -- or even several types. However, foods contain thousands of types of antioxidants -- vitamin A alone has several hundred forms -- and it's not known which of these substances are able to confer benefits. In fact, many researchers theorize that antioxidants in food form chemical networks that then interact with our own cellular and genetic intricacies.

Although supplements containing antioxidants are generally considered safe, some studies have suggested that taking higher doses of supplements, such as beta carotene or vitamin E, over time may actually increase your risk of death.

When it comes to antioxidant intake, no one food or food group should be your sole focus.

It's best to include a wide variety of foods as part of a healthy, well-balanced diet. Some of the better sources of antioxidants include:

Berries:

Blueberries, blackberries, raspberries, strawberries and cranberries are among the top sources of antioxidants.

Beans:

Small red beans and kidney, pinto and black beans are all choices rich in antioxidants.

Fruits:

Many apple varieties (with peel) are high in antioxidants, as are avocados, cherries, green and red pears, fresh or dried plums, pineapple, kiwi and others.

Vegetables: Those with the highest antioxidant content include artichokes, spinach, red cabbage, red and white potatoes (with peel), sweet potatoes and broccoli. Although the effect of cooking on antioxidant levels varies by cooking method and vegetable, one study showed that cooking generally increased levels among select vegetables.

Beverages:

Green tea may come to mind as a good source of antioxidants, but other beverages have high levels, too, including coffee, red wine and many fruit juices such as pomegranate.

Nuts:

Walnuts, pistachios, pecans, hazelnuts and almonds are some of the top nuts for antioxidant content.

Herbs:

These may be unexpected suppliers of antioxidants, but ground cloves, cinnamon and ginger, dried oregano leaf and turmeric powder are all good sources.

Grains:

In general, oat-based products are higher in antioxidants than are those derived from other grain sources.

And for dessert -- Don't forget that a piece of dark chocolate ranks as high or higher than most fruits and vegetables in terms of antioxidant content.

As a bonus, foods high in antioxidants typically offer many other health benefits.

These foods are often plant based and offer health benefits in addition to their antioxidant content, such as being high in fiber, protein, and other vitamins and minerals and low in saturated fat and cholesterol.

-- Donald Hensrud, M.D., Endocrinology, Mayo Clinic, Rochester, Minn.

(Medical Edge from Mayo Clinic is an educational resource and doesn't replace regular medical care. E-mail a question to medicaledge@mayo.edu , or write: Medical Edge from Mayo Clinic, c/o TMS, 2225 Kenmore Ave., Suite 114, Buffalo, N.Y., 14207. For more information, visit www.mayoclinic.org.)

(c) 2009 Mayo Foundation for Medical Education and Research. Distributed by Tribune Media Services Inc. All Rights Reserved.

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