Men who take beta-carotene supplements for 15 years or longer may have less cognitive decline, according to a report in the November 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals1.
Francine Grodstein, Sc.D., of Brigham and Women’s Hospital (BWH) and Harvard Medical School, Boston, and colleagues studied the antioxidant beta-carotene and its effect on cognitive ability in two groups of men. The long-term group included 4,052 men who in 1982 had been randomly assigned to take placebo or 50 milligrams of beta-carotene every other day. Between 1998 and 2001, an additional 1,904 men were randomly assigned to one of the two groups. Both groups were followed through 2003, completing yearly follow-up questionnaires with information about their health and their compliance with taking the pills. The men were assessed by telephone for cognitive function at least once between 1998 and 2002.
The long-term participants were treated for an average of 18 years and the short-term participants for an average of one year. Men in the short-term group displayed no differences in cognition regardless of whether they took beta-carotene or placebo, but men in the long-term group who took beta-carotene had significantly higher scores on several of the cognitive tests compared with men who took placebo.
An accompanying editorial2 noted the need for more studies on cognition and aging. Though the results are plausible, other potential explanations exist for beta-carotene’s neuroprotective effects, writes Kristine Yaffe, M.D., of the San Francisco VA Medical Center and University of California, San Francisco, in an accompanying editorial. For example, men who take pills as assigned for 18 years may have certain characteristics that make them less likely to lose cognitive abilities.