Doubt cast on vitamin D's role against disease
09 December, 2013
LONDON: Scientists have cast doubt on the value of vitamin D supplements to protect against diseases such as cancers, diabetes and dementia.
Writing in The Lancet Diabetes and Endocrinology, French researchers suggest low vitamin D levels do not cause ill health, although they did not look at bone diseases.
Recent evidence has shown it may also have a role to play in preventing non-bone-related diseases such as Parkinson's, dementia, cancers and inflammatory diseases.
Prof Philippe Autier, from the International Prevention Research Institute in Lyon, carried out a review of data from 290 prospective observational studies and 172 randomised trials looking at the effects of vitamin D levels on health outcomes, excluding bone health, up to December 2012.
A large number of the observational studies suggested that there were benefits from high vitamin D - that it could reduce the risk of cardiovascular events by up to 58%, diabetes by up to 38% and colorectal cancer by up to 33%.
But the results of the clinical trials - where participants were given vitamin D supplements - found no reduction in risk, even in people who started out with low vitamin D levels.
Recently England's chief medical officer said free vitamins should be given to all young children because more and more of them were being diagnosed with the bone disease rickets, lack of calcium and other bone and muscle diseases.
People with dark skin, such as people of African-Caribbean and South Asian origin, and people who wear full-body coverings, as well as pale-skinned people are also known to be at higher risk.
The Scientific Advisory Committee on Nutrition (SACN), an independent group of scientific experts who advise the government on nutrition, is currently reviewing the dietary recommendations for vitamin D for all population groups in the UK.