We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.
Impact of vitamin A supplementation on the incidence of infection in elderly nursing-home residents: a randomized controlled trial.
The aim of this study was to determine if vitamin A supplementation reduces the incidence of bacterial infections among elderly nursing-home residents. One hundred and nine patients were enrolled into a double-masked, placebo-controlled trial at an academically affiliated nursing home. Fifty-six patients received a single capsule containing 1,000 IU of vitamin A (placebo) and 53 received a single capsule containing 200,000 IU of vitamin A. Antibiotic-treated infections were enumerated for 90 days after dosing and infection rates were expressed per 1000 days of follow-up. There were 42 antibiotic-treated infections altogether, 21 in each group. The infection rates in the vitamin A and placebo groups were 4.7 and 4.3 per 1,000 days of follow-up, respectively (relative risk 1.1; 95% CI 0.6, 2.0). The findings of this study do not support a role for vitamin A supplements for the prevention of infections among frail elderly nursing-home patients.