The growing interest in primary prevention of cognitive impairment and dementia has been sparked by several promising interventions, most of which have not been confirmed by recently conducted randomized clinical trials. Many observational studies, but not all, have suggested that antioxidant supplements, including beta carotene, or a diet with high intake of antioxidants reduce the risk of developing Alzheimer disease (AD) or other forms of cognitive impairment. These results, along with those from an Alzheimer Disease Cooperative Study (ADCS) trial published in 1997,1 which showed a benefit of vitamin E treatment (2000 IU/d) for 2 years in reducing progression of AD,have sparked interest in antioxidants for treatment or prevention of cognitive disorders.
Yaffe K. Antioxidants and Prevention of Cognitive DeclineDoes Duration of Use Matter?. Arch Intern Med. 2007;167(20):2167-2168. doi:10.1001/archinte.167.20.2167