Sunday, November 18, 2007

Beta-carotene supplementation long-term may delay mental decline

Beta-carotene supplementation long-term may delay mental decline

Beta-carotene supplementation long-term may delay mental decline In a newly published study, researchers tested the cognitive function of participants in the Physicians' Health Study II (PHSII), a continuation of the Physicians' Health Study (PHS) trial looking at the effects of beta-carotene and other vitamin supplements on chronic disease. The subjects included participants from the original PHS (started in 1982) and newer recruits from 1998.

The researchers tested the general cognition, verbal memory, and category fluency of 5,956 participants, including 4,052 participants from the PHS with a minimum supplementation period of 18 years. Among the 1,904 newly recruited subjects (average supplementation of 1 year) no differences in cognition were evident whether they took beta-carotene or the placebo.

However, among the long-term supplement users from the PHS, the mean global score (average of all tests) was significantly higher in the beta carotene group than in the placebo. On verbal memory, men receiving long-term beta carotene supplementation also performed significantly better than the placebo group. The potential mechanism for the protective effects could be related to the role of vitamin A and beta-carotene on beta-amyloid protein production in the brain. The build-up of plaque from beta-amyloid deposits is associated with oxidative stress, cell death, and increased risk of Alzheimer's disease.

The study is the first to look at long-term antioxidant supplementation in relation to a decline in cognitive function that occurs naturally with age, and that precedes diseases such as Alzheimer's.

Arch Intern Med. 2007;167(20):2184-2190.
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