DHAKA: 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.

More clinical trials on non-skeletal diseases are needed, they say.

Vitamin D supplements are recommended for certain groups.

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 found no reduction in risk, even in people with low vitamin D levels.

And a further analysis of recent randomised trials found no positive effect of vitamin D supplements on diseases occurring.

Prof Autier said: "What this discrepancy suggests is that decreases in vitamin D levels are a marker of deteriorating health.

"Ageing and inflammatory processes involved in disease occurrence... reduce vitamin D concentrations, which would explain why vitamin D deficiency is reported in a wide range of disorders."

Source: BBC
BDST: 1128 HRS, DEC 06, 2013