Taking vitamin supplements to prevent Alzheimer’s and keep the brain sharp is a waste of money, Oxford scientists have concluded.B vitamins fail to slow mental decline and do not prevent dementia, a comprehensive analysis of evidence has found. Middle-aged people are better off taking a walk or eating more fruit and vegetables, experts say.
People taking supplements scored no better on tests of memory, speed or decision-making than those taking placebos, according to an overview of data on 22,000 people in 11 different trials.
“Our study draws a line under the debate. B vitamins don’t reduce cognitive decline as we age. Taking folic acid and vitamin B-12 is sadly not going to prevent Alzheimer’s disease,” said Dr Robert Clarke of the clinical trials service unit at Oxford University.
The millions of people who spend £10 a time on packs of vitamins are doing their health no good, Dr Clarke added.“Taking supplements like B vitamins doesn’t prevent heart disease, stroke or cognitive decline,” he said.
“About 25–30 per cent of the adult population take multivitamins, often with the idea that they are also good for the heart or the brain, but the evidence just isn’t there. Much better is to eat more fruit and vegetables, avoid too much red meat and too many calories, and have a balanced diet.”
About 800,000 people in Britain have dementia, and David Cameron has committed to international efforts to find a cure in little more than a decade. Many consider the idea of reversing symptoms too optimistic, with hope currently focusing on the possibility of stopping the disease in its tracks before the brain is ravaged. Over the past decade, however, 99.6 per cent of trials have failed.
Alzheimer’s patients have been found to have higher levels of a compound called homocysteine in the blood, and people with higher levels of the chemical are more likely to develop the disease. This led some scientists to hope that taking folic acid and vitamin B-12, which are known to cut homocysteine levels, could help to prevent the disease and some small studies suggested they might be right.
Dr Clarke’s team analysed all known randomised trials looking at the effects of B vitamins on older people’s brains. While supplements did see homocysteine levels fall, this had no effect on mental abilities, the researchers write in the American Journal of Clinical Nutrition. Dr Clarke said it was now clear that almost all vitamin supplements were useless, adding: “All available evidence on the available ones have not shown a benefit for the prevention of heart disease, stroke or cognitive decline.”
Evidence has shown, however, that women taking folic acid supplements while pregnant cut their risk of giving birth to a baby with neural tube defects. The jury is still out on vitamin D, and the NHS says the elderly and children under five could benefit.
Simon Ridley, head of research at Alzheimer’s Research UK, said the results were disappointing but rigorous. “This comprehensive review of several trials shows that B vitamins have not been able to slow mental decline as we age, nor are they likely to prevent Alzheimer’s,” he said.