Our August Travel Rx column focused on fighting free radicals with a healthy diet rich in antioxidants. Read on to learn about the health risks of low levels of antioxidants and current research on antioxidant supplements.

Antioxidants protect cells from oxidative damage, which is caused by free radicals. Free radicals are highly unstable chemicals that react with and destroy healthy cells. They are byproducts of normal metabolism, but their prevalence can be exacerbated by exposure to environmental chemicals such as air pollution and tobacco smoke. Free radicals set off chain reactions that can only be stopped by a cell’s antioxidant defense system.

Studies suggest that low levels of antioxidants in the body play a role in a range of health problems, including heart disease, stroke, periodontal disease, cancer, retinal damage and low sperm count.

Oxidative stress contributes to aging and aging-related impairments in memory, according to some research, and there is some conjecture that high antioxidant levels, within reason, could promote longevity and reduce the risk of dementia associated with normal aging and neurodegenerative disorders such as Alzheimer’s disease.

Low levels of nutrients, including minerals such as zinc and antioxidant vitamins A, C and E, may be contributing factors in wet and dry macular degeneration, a disease which affects the macula — the part of the eye responsible for central vision — causing blurred central vision or a blind spot in the center of the visual field. The National Eye Institute is sponsoring a clinical trial to assess the role of specific antioxidants — lutein, zeaxanthrin and omega 3 fatty acids — in lowering the risk of macular degeneration. Lutein and zeaxanthrin are found in high concentrations in egg yolks, corn and spinach and other leafy green vegetables. Omega-3 fatty acids are found in fish and certain nuts such as almonds.

The Age Related Eye Disease Study, also sponsored by the National Eye Institute, showed that taking high-dose formulations of antioxidants (vitamins C and E and beta carotene) plus zinc significantly reduced the risk of advanced age-related macular degeneration and its associated vision loss, but that these same nutrients had no significant effect on the development or progression of cataracts. The daily supplement was shown to reduce the risk of progressing to moderate or severe vision loss by up to 25 percent.

Several studies have shown that the risk of rheumatoid arthritis is highest among people with the lowest levels of dietary antioxidants, and a recent pilot study suggests that proper antioxidant intake may help relieve symptoms of the chronic inflammatory condition.

Nutrition studies have produced mixed messages on whether women can decrease their risk of breast cancer by controlling diet. Carotenoids show some promise of protection. The Nurses’ Health Study II suggests that, along with other factors such as increased physical activity, higher intakes of specific carotenoids (beta-carotene, lutein and zeaxanthrin), dietary fiber and unsaturated fat during adolescence and early adult life reduce the risk of pre-menopausal breast cancer. However, the results may not be applicable to a wider population or may be due to factors other than diet.

Other studies have shown limited support for the use of antioxidant supplements in reducing the risk of breast cancer recurrence or breast cancer-related mortality.

While research suggests that glutathione or other antioxidants might be beneficial when used as a supplement to prevent chronic periodontitis and assist in the healing process, evidence is inconclusive as to whether they are safe.

The debate continues over the value of antioxidant supplements. Most studies have shown that supplements are neither harmful nor beneficial. On the other hand, recent reports claim that excessive intake of vitamin and mineral supplements can do harm in some cases. A handful of studies have led to recommendations of specific vitamin and mineral supplementation, but what worked in the lab has not always translated to positive results in human studies. It is not completely understood why individual antioxidants taken as supplements have not proven to be nearly as effective as foods rich in antioxidants.

The debate continues over the value of antioxidant supplements. Most studies have shown that supplements are neither harmful nor beneficial. On the other hand, recent reports claim that excessive intake of vitamin and mineral supplements can do harm in some cases.

A handful of studies have led to recommendations of specific vitamin and mineral supplementation, but what worked in the lab has not always translated to positive results in human studies. It is not completely understood why individual antioxidants taken as supplements have not proven to be nearly as effective as foods rich in antioxidants.

According to Eric Klann, Ph.D., professor of molecular physiology and biophysics at Baylor College of Medicine, the balance of oxidants is very important. “In animal studies, it’s bad to have too much or too little. That could be part of the reason for conflicting findings on antioxidant supplements in humans.”

As we wait for more research results, consider that most vegetables contain fewer calories per ounce than other foods. Filling up on greens can help you maintain a healthy weight because you can eat more of them more often. Research continues to show that foods containing these ingredients are much better than supplements at lowering blood pressure, preventing heart disease and decreasing cancer risk.

Although the health benefits of antioxidant supplements remain in question, the safe way to increase your antioxidant intake is to add fruits and vegetables to your diet. If you consider taking supplements, talk to your doctor before trying them on your own.