Diminshing cognitive functions such as deterioration in memory, reduced ability to process information quickly, and reduced verbal fluency have been linked to risk of dementia in old age. Taking supplements of folic acid may significantly improve cognitive function in older men and women.

A group of 818 men and women over-50s were followed for three years. Some were given 800 micrograms of a synthetic form of folic acid per day, the rest took a placebo. The scientists found that the group who took the folic acid improved on all aspects of cognitive functioning compared to the group that took the placebo.

Some research studies have linked folic acid supplement taking with reductions in various age-related impairments such as hearing loss and Alzheimer's. Others are not so clear, but there seems to be consensus that it helps improve cognitive function in elderly people with high concentrations of the amino acid homocysteine in their blood, which could indicate increased riks of stroke, heart disease and Alzheimer's.

The study was led by Jane Durga from the Wageningen University in The Netherlands and is to be published in the Lancet.