Meta-analysis concludes protective effect for vitamin D supplements against colds, flu – ProHealth
February 17 2017. The authors of a meta-analysis published on February 17, 2017 in the BMJ affirmed that, despite some previous conflicting study conclusions, supplementing with vitamin D is associated with a lower risk of influenza and colds. “This major collaborative research effort has yielded the first definitive evidence that vitamin D really does protect against respiratory infections,” announced first author Adrian Martineau of Queen Mary University of London. “Our analysis of pooled raw data from each of the 10,933 trial participants allowed us to address the thorny question of why vitamin D ‘worked’ in some trials, but not in others.
The meta-analysis included 25 randomized, double blind, placebo controlled trials that evaluated the effects of vitamin D2 or vitamin D3 supplementation on the risk of developing a cold or flu. The reduction in risk of acute respiratory infection associated with vitamin D was comparable to that of an influenza vaccine against flu risk. “The protective effects of vitamin D supplementation are strongest in those who have the lowest vitamin D levels, and when supplementation is given daily or weekly rather than in more widely spaced doses,” Dr Martineau reported.
“Vitamin D fortification of foods provides a steady, low-level intake of vitamin D that has virtually eliminated profound vitamin D deficiency in several countries,” he added. “By demonstrating this new benefit of vitamin D, our study strengthens the case for introducing food fortification to improve vitamin D levels in countries such as the UK where profound vitamin D deficiency is common.”
“Most people understand that vitamin D is critical for bone and muscle health,” stated senior author Carlos Camargo, MD, DrPH. “Our analysis has also found that it helps the body fight acute respiratory infection, which is responsible for millions of deaths globally each year.”