Are Antioxidants the “Fountain of Youth”?

January 3, 2008—Growing evidence indicates that antioxidants might slow aging. Now a new study has found that beta-carotene supplements prevent changes to the brain associated with aging.

Oxidation is the primary cause of damage to cells, organs, and tissues throughout the body. As the body ages, its ability to repair oxidative damage slows down, and the results are the changes we generally associate with aging: wrinkles, gray hair, the need for reading glasses, and so on. Slow diminishment of brain (cognitive) function, which can eventually lead to dementia, is also caused by oxidative damage.

Antioxidants are special nutrients that prevent and repair oxidation’s damaging effects. Beta-carotene; vitamins A, C, and E; and the minerals zinc and selenium are the best-known of the antioxidant nutrients, and a countless array of plant chemicals known as bioflavonoids appear to be even stronger antioxidants.

The new study, published in the Archives of Internal Medicine, included 5,956 men over 65 who had been using 50 mg (about 83,000 IU) of beta-carotene every other day or a non-nutritive substance (placebo) as part of the Physician’s Health Study or the follow-up Physician’s Health Study II. The men from the original study had been taking either beta-carotene or placebo for an average of 18 years at the time they underwent cognitive testing for the current study; for men who enrolled only in the follow-up study, the average treatment time was one year.

Supplementing with beta-carotene was associated with better scores on cognitive tests in the men from the original study, but not in the new recruits for the follow-up study. The researchers found that using beta-carotene for three years or less had no impact on cognitive performance, but using beta-carotene for 15 years or more seemed to prevent age-related cognitive decline. They estimated that the difference in brain function between the men who used long-term beta-carotene and those who did not was similar to the cognitive decline that elderly men can expect over 1 to 1.5 years

“This information helps us to understand how eating a good diet—lots of fruits and vegetables—protects the brain,” commented Erika Kellerhalls, MD, who practices family medicine in British Columbia, Canada. “There are a number of studies showing that we can prevent, or at least slow, age-related changes in cognition. The results from this study suggest that beta-carotene might be one reason for this effect. Most likely the combination of antioxidants that occur naturally in plant foods has the best effect, but it clearly requires a lot of time.”

Foods rich in beta-carotene include orange, red, and yellow vegetables and fruits such as carrots, sweet potato, squash, tomatoes, and apricots. Greens, such as spinach, broccoli, and kale also have high amounts of beta-carotene and other related carotenes.

(Arch Intern Med 2007;167:2184–90)

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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