Eating fish - long considered 'brain food' - may really be good for the old grey matter, as is a healthy dose of sunshine, new research suggests.
University of Manchester scientists in collaboration with colleagues from other European centres have shown that higher levels of vitamin D - primarily synthesised in the skin following sun exposure but also found in certain foods such as oily fish - are associated with improved cognitive function in middle-aged and older men.
The study, published in the Journal of Neurology, Neurosurgery and Psychiatry, compared the cognitive performance of more than 3,000 men aged 40 to 79 years at eight test centres across Europe.
The researchers found that men with higher levels of vitamin D performed consistently better in a simple and sensitive neuropsychological test that assesses an individual's attention and speed of information processing.
"Previous studies exploring the relationship between vitamin D and cognitive performance in adults have produced inconsistent findings but we observed a significant, independent association between a slower information processing speed and lower levels of vitamin D," said lead author Dr David Lee, in Manchester's School of Translational Medicine.
"The main strengths of our study are that it is based on a large population sample and took into account potential interfering factors, such as depression, season and levels of physical activity.
"Interestingly, the association between increased vitamin D and faster information processing was more significant in men aged over 60 years, although the biological reasons for this remain unclear."
"The positive effects vitamin D appears to have on the brain need to be explored further but certainly raise questions about its potential benefit for minimising ageing-related declines in cognitive performance."