Vitamin D supplements can help prevent acute respiratory tract infections, particularly among very deficient individuals.
That’s according to findings from a new systematic review and meta-analysis of data from 25 randomised controlled trials of vitamin D supplementation, published in The BMJ .
After adjusting for other potentially influential factors, the researchers found that vitamin D supplementation resulted in a 12 per cent reduction in the proportion of participants experiencing at least one acute respiratory tract infection. The protective effects were strongest among those with severe vitamin D deficiency (less than 25 nmol/L baseline blood levels) and the researchers calculated that four people in this group would need to take supplements to prevent one acute respiratory tract infection.
The researchers say their findings “support the introduction of public health measures such as food fortification to improve vitamin D status in settings where profound vitamin D deficiency is common.”
In a linked editorial however, Mark Bolland from the University of Auckland and Alison Avenell from the University of Aberdeen , said the clinically useful effect of such supplements remains uncertain and requires confirmation in well-designed adequately powered randomised controlled trials.