A study of 3,000 European men has indicated that vitamin D helps to keep us mentally agile in later life.

The research was carried out by David Lee and colleagues at the University of Manchester in the UK, and published in the Journal of Neurology, Neurosurgery and Psychiatry.

Reuters report that:

The researchers compared the cognitive performance of more than 3,000 European men aged 40 to 79 and found those with low vitamin D levels did more poorly on a task designed to test mental agility.

Differences in education levels, physical activity and depression levels were all taken into account, and David Lee explained that:

When we adjusted for all these other health and lifestyle factors we still found that there was a link between vitamin D and the cognitive outcome.

The researchers aren't sure why vitamin D appears to help older folk stay mentally fit, but believe it may be related to hormone activity or neuron production in the brain.

Vitamin D is produced when the skin is exposed to sunlight (without sun block). But, you can also get vitamin D by eating oily fish, and (to a smaller extent) eggs, or from fortified foods such as milk, breakfast cereal, orange juice, and margarine.

David Lee said that the study findings should not encourage people to spend excess time in the sun (due to the risk of skin cancer), but that supplementation was an easy and effective way to ensure an adequate vitamin D intake.