Long-Term Beta Carotene Use May Slow Cognitive Decline in Men

Long-term use of beta carotene supplements may modestly slow the mental decline of aging, according to the Physicians' Health Study II.
The analysis — in the Archives of Internal Medicine — was based on about 4000 men randomized at a mean age of 56 to take 50 mg of beta carotene or placebo on alternate days. After 18 years, those taking beta carotene had slightly better cognition on a variety of tests. The effect was the equivalent of delaying cognitive aging by 1 to 1.5 years. A second group of men randomized to short-term beta carotene supplementation (average of 1 year) did not see any cognitive benefit.
The authors say small differences in cognition could "predict substantial differences in eventual risk of dementia; thus, the public health impact of long-term beta carotene use could be large."
However, an editorialist cautions that results of other trials have been mixed, and "for the clinician, there is no convincing justification to recommend" antioxidants for cognitive performance.