<p> Vitamin D supplements may protect against acute respiratory infections including colds and flu, according to scientists who analysed data from 14 countries including India and Afghanistan.<br /><br /></p>.<p>The study led by Queen Mary University of London (QMUL) provides the most robust evidence yet that vitamin D has benefits beyond bone and muscle health.<br /><br />The results are based on a new analysis of raw data from around 11,000 participants in 25 clinical trials conducted in 14 countries including the UK, US, Japan, India, Afghanistan, Belgium, Italy, Australia and Canada.<br /><br />"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," said Professor Adrian Martineau from QMUL.<br /><br />"The bottom line is that 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," he said.<br /><br />"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.<br /><br />"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," Martineau said.<br /><br />Vitamin D - the 'sunshine vitamin' - is thought to protect against respiratory infections by boosting antimicrobial peptide levels in the lungs.<br /><br />Results of the study fit with the observation that colds and flu are the most common in winter and spring, when levels of vitamin D are at their lowest.<br /><br />They may also explain why vitamin D protects against asthma attacks, which are commonly triggered by respiratory viruses.<br /><br />Daily or weekly supplementation halved the risk of acute respiratory infection in people with the lowest baseline vitamin D levels, below 25 nanomoles per litre.<br /><br />However, people with higher baseline vitamin D levels also benefited, although the effect was more modest (10 per cent risk reduction).<br /><br />The reduction in risk of acute respiratory infection induced by vitamin D was on a par with the protective effect of injectable 'flu vaccine against 'flu-like illnesses.<br /><br />Acute respiratory infections are a major cause of global morbidity and mortality. Upper respiratory infections such as colds and 'flu are the commonest reason for GP consultations and days off work.<br /><br />Acute lower respiratory infections such as pneumonia are less common, but caused an estimated 2.65 million deaths worldwide in 2013.<br /><br />Vitamin D supplementation is safe and inexpensive, so reductions in acute respiratory infections brought about by vitamin D supplementation could be highly cost-effective.<br />The study was published in the journal BMJ. <br /></p>
<p> Vitamin D supplements may protect against acute respiratory infections including colds and flu, according to scientists who analysed data from 14 countries including India and Afghanistan.<br /><br /></p>.<p>The study led by Queen Mary University of London (QMUL) provides the most robust evidence yet that vitamin D has benefits beyond bone and muscle health.<br /><br />The results are based on a new analysis of raw data from around 11,000 participants in 25 clinical trials conducted in 14 countries including the UK, US, Japan, India, Afghanistan, Belgium, Italy, Australia and Canada.<br /><br />"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," said Professor Adrian Martineau from QMUL.<br /><br />"The bottom line is that 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," he said.<br /><br />"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.<br /><br />"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," Martineau said.<br /><br />Vitamin D - the 'sunshine vitamin' - is thought to protect against respiratory infections by boosting antimicrobial peptide levels in the lungs.<br /><br />Results of the study fit with the observation that colds and flu are the most common in winter and spring, when levels of vitamin D are at their lowest.<br /><br />They may also explain why vitamin D protects against asthma attacks, which are commonly triggered by respiratory viruses.<br /><br />Daily or weekly supplementation halved the risk of acute respiratory infection in people with the lowest baseline vitamin D levels, below 25 nanomoles per litre.<br /><br />However, people with higher baseline vitamin D levels also benefited, although the effect was more modest (10 per cent risk reduction).<br /><br />The reduction in risk of acute respiratory infection induced by vitamin D was on a par with the protective effect of injectable 'flu vaccine against 'flu-like illnesses.<br /><br />Acute respiratory infections are a major cause of global morbidity and mortality. Upper respiratory infections such as colds and 'flu are the commonest reason for GP consultations and days off work.<br /><br />Acute lower respiratory infections such as pneumonia are less common, but caused an estimated 2.65 million deaths worldwide in 2013.<br /><br />Vitamin D supplementation is safe and inexpensive, so reductions in acute respiratory infections brought about by vitamin D supplementation could be highly cost-effective.<br />The study was published in the journal BMJ. <br /></p>