Supplementation with antioxidants, zinc or copper has neither a beneficial nor harmful effect on cognition in elderly people, a new study indicates.

“Oxidative pathways” are thought to be involved in common forms of dementia, Dr. Kristine Yaffe, of the University of California, San Francisco, and colleagues note in the medical journal Neurology.

Also, the authors point out, “Several observational studies of non-demented older adults have suggested that high antioxidant dietary intake or the use of antioxidant supplements is associated with better cognitive performance.”

With this background, the researchers examined the effects of daily antioxidant and/or mineral supplements on the mental abilities of elderly participants in the Age-Related Eye Disease Study.

The subjects were randomly assigned to take antioxidants (500 milligrams of vitamin C, 400 units of vitamin E, and 15 milligrams of beta carotene); or 80 milligrams of zinc and 2 milligrams of copper; or antioxidants plus zinc and copper; or placebo.

A year before entering the study, the participants’ dietary intake was assessed using a standardized food questionnaire.

After an average of 6.7 years, a total of 2166 patients who completed study underwent a battery of tests to evaluate their cognitive powers.

No significant differences were seen between any of the groups on any of the eight parts of the six tests administered, Yaffe and her colleagues report.

The team concludes that the likelihood of developing mental impairment is not significantly affected by any of the supplements tested.

SOURCE: Neurology, November 9, 2004.