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This Supplement May Lower the Risk of Severe Flu Grace Cary – Getty Images<\/p>\n
New research finds that people low in this vitamin may be more likely to get severe flu infections.<\/p>\n
Scientists say that vitamin D, specifically, may help lower certain groups\u2019 risks of severe complications from a respiratory infection.<\/p>\n
Doctors say many may benefit from a vitamin D supplement.<\/p>\n
Cases of the flu continue to be high<\/a> around the country, thanks to the highly infectious subclade K variant<\/a>. While there are plenty of natural ways to boost your immune system, new research points to a supplement that may help curb severe reactions to the flu: vitamin D.<\/p>\n That\u2019s the takeaway from new research published in The American Journal of Clinical Nutrition.<\/a> For the study, researchers analyzed health data from 36,258 people who participated in the UK Biobank, a long-term biomedical research resource.<\/p>\n The researchers discovered that people with a severe vitamin D deficiency<\/a> (measured as less than 15 nmol\/L) had a 33% higher rate of being hospitalized for a respiratory tract infection compared to those who had vitamin D levels of 75 nmol\/L or higher. For each 10 nmol\/L increase in vitamin D, the hospitalization rate for respiratory tract infections dropped by 4%.<\/p>\n Given that 18%<\/a> of Americans have inadequate vitamin D levels, this is worth paying attention to.<\/p>\n Meet the experts: Amesh A. Adalja, M.D.<\/a>, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security; Thomas Russo, M.D.,<\/a> a professor and chief of infectious diseases at the University at Buffalo in New York; Jessica Cording, R.D., C.D.N., author of The Little Book of Game-Changers; William Schaffner, M.D.,<\/a> an infectious disease specialist and professor at the Vanderbilt University School of Medicine<\/p>\n This isn\u2019t the first study<\/a> to link low levels with a higher risk of respiratory infections, raising questions about whether you should be focused on your own levels of the nutrient. Here\u2019s what doctors and a dietitian want you to keep in mind.<\/p>\n Why may vitamin D lower the risk of severe respiratory infection?<\/p>\n The researchers didn\u2019t dive into that, but doctors aren\u2019t shocked by these findings. \u201cVitamin D plays a role in optimal immune system function,\u201d says Amesh A. Adalja, M.D.<\/a>, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security.<\/p>\n Vitamin D enhances both your innate immunity<\/a>\u2014your body\u2019s first line of defense against pathogens\u2014and your adaptive immunity<\/a>, which is the part of your immune system that \u201clearns\u201d to fight certain germs after you\u2019ve been exposed to them, explains Thomas Russo, M.D.,<\/a> a professor and chief of infectious diseases at the University at Buffalo in New York. \u201cAppropriate vitamin D concentrations are important for an optimal immune response,\u201d he says, noting that even having a \u201cmoderate\u201d deficiency in vitamin D may impact your immune system.<\/p>\n But it\u2019s important to keep two things in mind with this particular study: One is that it\u2019s observational, so researchers simply found an association between having low vitamin D and a greater risk of serious infection. The other is that they focused on those with a severe deficiency.<\/p>\n \u201cThe literature around vitamin D [supplementation] is yes and no in terms of whether it\u2019s helpful,\u201d says William Schaffner, M.D.,<\/a> an infectious disease specialist and professor at the Vanderbilt University School of Medicine. \u201cIt would appear the more severe your vitamin D deficiency is, the more likely your immune system is not functioning optimally.\u201d<\/p>\n How much vitamin D do you need?<\/p>\n The recommended daily allowance (RDA) of vitamin D depends on your age and life stage. However, most adults should get 600 international units (IU) daily, according to the National Institutes of Health<\/a> (NIH). (People who are 70 and older should have 800 IU of vitamin D.)<\/p>\n What are the signs I\u2019m not getting enough vitamin D?<\/p>\n Vitamin D deficiency is more common in people who are lactose intolerant, follow a vegan diet, or those who have limited exposure to sunlight, per the NIH. Symptoms of low vitamin D can be vague or even hard to detect at all, but these are commonly linked to the status, according to Jessica Cording, R.D., C.D.N., author of The Little Book of Game-Changers:<\/p>\n Bone fractures (usually only in severe cases)<\/p>\n How to get more vitamin D<\/p>\n