A daily multivitamin and mineral supplement may reduce cognitive decline in older people, according to a US study that is the first to demonstrate they may benefit ageing brain function.
The trial, involving more than 2,200 over-65s, suggests that daily supplements may slow cognitive decline by about 60%, or nearly two years, with the most substantial effects seen in older people with a history of cardiovascular disease.
But while experts in Alzheimer’s disease and dementia are encouraged by the findings, they caution that larger studies are needed to confirm the effect before recommending daily multivitamins to help protect older people from cognitive decline. Previous tests of dietary supplements have had no effect on the disease.
“We provide the first evidence in a long-term, randomised controlled trial of older women and men that daily use of a safe, readily accessible, and low-cost multivitamin-mineral can improve cognition,” the researchers wrote in Alzheimer’s and Dementia, the Journal of the Alzheimer’s Association. “This finding could have important public health implications for brain health and resilience against future cognitive decline.”
With populations ageing around the world, dementia has become one of the leading global health challenges, but there are no drugs that can cure any of the common types. In the UK, about 850,000 people live with dementia, most of which is Alzheimer’s disease or “vascular dementia”. People over 65, and those with diabetes, high blood pressure, high cholesterol and depression, are most at risk.
Researchers at Wake Forest University in North Carolina and Brigham and Women’s Hospital in Boston investigated whether a daily cocoa extract or multivitamins with minerals improved memory and other mental tasks in 2,262 people aged 65 and over. The researchers rated the participants’ “global cognition” before and during the three-year trial through tests involving word lists, number problems, verbal fluency and story recall.
Cocoa extract is rich in substances called flavanols and past research has suggested that they may have some benefit for brain function. But the latest trial found daily cocoa supplements made no difference to people’s cognitive performance. Daily multivitamin-mineral supplements, however, appeared to improve cognitive scores, in particular for those with cardiovascular disease, a known risk factor for dementia. The results suggest “either greater relative improvement or more protection from cardiovascular disease-related cognitive decline”, the authors wrote.
Prof Laura Baker, co-principal investigator on the Cosmos study at Wake Forest University, said it was too early to recommend daily multivitamins to prevent cognitive decline. “While these preliminary findings are promising, additional research is needed in a larger and more diverse group of people. Also, we still have work to do to better understand why the multivitamin might benefit cognition in older adults,” she said.
Prof Tara Spires-Jones, group leader at the UK Dementia Research Institute at Edinburgh University, said the study was well conducted, but noted that most people involved were highly educated white people.
“It will be important to confirm that the results hold up in the wider population,” she said. “It is also not clear from this study whether multivitamin use will prevent diseases affecting cognition like Alzheimer’s disease. Several dietary supplements have been tested as treatments for Alzheimer’s disease and so far none have been effective.”
Dr Maria Carrillo, chief scientific officer at the Alzheimer’s Association, said: “This is the first positive, large-scale, long-term study to show that multivitamin-mineral supplementation for older adults may slow cognitive ageing. While the Alzheimer’s Association is encouraged by these results, we are not ready to recommend widespread use of a multivitamin supplement to reduce risk of cognitive decline in older adults.
“Independent confirmatory studies are needed in larger, more diverse study populations,” she added. “It is critical that future treatments and preventions are effective in all populations.”