The study adds to an ever growing body of science supporting the benefits of maintaining healthy vitamin D levels.
In adults, it is said vitamin D deficiency may precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases. There is also some evidence that the vitamin may reduce the incidence of several types of cancer and type-1 diabetes.
The first study, which followed 3,113 men across Europe aged between 40 and 79, found that higher blood levels of vitamin D were associated with better performance in tests of attention and speed of information processing.
Results of the European Male Ageing Study (EMAS) are published online in the Journal of Neurology, Neurosurgery and Psychiatry.
?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, from 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.?
Dr Lee said that further study should focus on how the vitamin may improve brain function, but the findings ?certainly raise questions about its potential benefit for minimising ageing-related declines in cognitive performance?.
? and breathe easily
Researchers from the University of Pennsylvania report that vitamin D may also slow the progressive decline in breathing that can occur in asthmatics as a result of human airway smooth muscle (HASM) proliferation.
According to findings presented at the American Thoracic Society?s 105th International Conference in San Diego, calcitriol, a form of vitamin D synthesized within the body, could reduce growth-factor-induced HASM proliferation, which leads to reduced lung function over time. The researchers tested cells isolated from both asthmatics and non-asthmatics.
?Calcitriol has recently earned prominence for its anti-inflammatory effects,? explained lead researcher Gautam Damera, PhD. ?But our study is the first to reveal the potent role of calcitriol in inhibiting ASM proliferation.?
Using cells obtained from 12 subjects, the researchers found that calcitriol inhibited HASM by 60 per cent, while dexmethasone, a corticosteroid prescribed widely for the treatment of asthma, had little effect on HASM growth.
Commenting on the mechanism, Dr. Damera and his colleagues proposed that the vitamin may inhibit the activation of distinct set of proteins responsible for cell-cycle progression.
Future research in the area will include a randomized control trial of calcitriol in patients with severe asthma, with results expected in about a year?s time.
Source: Journal of Neurology, Neurosurgery and Psychiatry
May 2009, doi:10.1136/jnnp.2008.165720
?Association between 25-hydroxyvitamin D levels and cognitive performance in middle-aged and older European men?
Authors: D.M. Lee, A. Tajar, A. Ulubaev, N. Pendleton, T.W. O'Neill et al.