Stay Sharp with Beta-Carotene

December 12, 2007

There is solid scientific thinking behind the belief that antioxidant nutrients should help protect the brain as it ages. But when it comes to actual results in human studies, results have been mixed. Some have shown benefit, others haven’t.

A new study by researchers at Harvard University provides some support that, in the case of beta-carotene, long-term supplementation may help stop cognitive decline.

The study involved 5,956 men over age 65 enrolled in the Physician’s Health Study (PHS) II. Some 4,052 subjects were continuing participants from the first PHS who had received either 50 mg (83,350 IU) of beta-carotene or a placebo on alternate days for a mean duration of 18 years. Another 1,904 subjects were newly recruited for PHS II and received beta-carotene or placebo for a mean period of 1 year.

At the end of the intervention, the continuing participants from the first PHS had cognitive test scores that were significantly higher in the beta-carotene group, compared to the placebo group. The tests assessed general thinking ability, verbal memory (remembering a string of words) and category fluency (the ability to quickly come up with words in a certain category, for instance, “things that are hot”).

Among the newly recruited participants, cognition was similar in the beta-carotene and placebo groups. The researchers make several points:

The development of cognitive impairment appears to take years, if not decades, and data from animal models indicate that brain aging starts early in adult life.
Long-term oxidative stress appears to be a major factor in declining cognition.
Long-term supplementation, beginning at midlife, may be necessary to achieve cognitive benefits.
Even though benefits may seem small, modest differences in cognition, especially verbal memory, predict substantial differences in the eventual risk of dementia.

Bottom line: It may take 10 years or longer to begin to see cognitive benefits from supplementation, but in the end, it really can make a difference. In addition to beta-carotene, vitamins E and C also provide benefits with long-term use.

Other best bets?

Exercise daily.
Don’t smoke.
Take a multi-vitamin to get enough important B vitamins.
Take low-dose aspirin daily.
Take curcumin (found in the turmeric) for extra antioxidant protection. (See our article, “Exciting New Research on Curcumin, Alzheimer’s and Cancer,” July 31, 2007)
Take Ginkgo biloba, fish oil and green tea. (See our news archives for studies that support these suggestions.)