Vitamin D is mental health aid

US and the UK have looked at 2 000 people aged 65 and over. They found that compared to those with the highest vitamin D levels, those with the lowest were more than twice as likely to have impaired understanding.

in maintaining bone health, in the absorption of calcium and phosphorus, and in helping the immune system. People obtain the vitamin from exposure to sunlight, foods such as oily fish, and foods that are fortified with vitamin D, such as milk, cereals, and soya drinks. But older people's skin is less able to absorb vitamin D from sunlight so they are more reliant on obtaining it from

other sources.

have previously suggested that the vitamin can have a beneficial effect on cognitive function.

But the team from the Peninsula Medical School in Exeter, the University of Cambridge and the University of Michigan, assessed people's cognition, or comprehension skills. People who have impaired cognitive function are more likely to develop dementia. The researchers looked at people who had taken part in the Health Survey for England in 2000.

significant cognitive impairment, assessed by looking at people's attention, orientation in time and space and memory. The study found that as levels of vitamin D went down, levels of cognitive impairment went up.