In December 2018 researchers from Italy published their review of the medical scientific literature to assess the effect of vitamin and mineral supplementation on cognitive function in cognitively healthy people, aged 40 years and over. B vitamins, antioxidant vitamins, combinations of both and, where possible, minerals were considered separately. A total of 28 studies with more than 83,000 individuals who had taken vitamin or mineral supplements orally for at least three months were included in the review. Results showed no real evidence that any vitamin or mineral supplementation had any meaningful effect on cognitive decline or dementia, although the quality of evidence was considered moderate to low and did not permit any definitive conclusions being made. The only possible beneficial effect came from studies of long-term supplementation with antioxidant vitamins and these may be the most promising for further research.
Rutjes AW et al. Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life. Cochrane Database Syst Rev. 2018 Dec 17;12:CD011906