According to a professor of Medicine at Harvard Medical School: "Our study design provides strong evidence that the association between low vitamin D and respiratory infections is causal and that treating low vitamin D levels in children with an inexpensive and safe supplement will prevent some respiratory infections," says Camargo. He went on to say: "In almost 250 children with low blood levels of vitamin D during winter, we found that taking a daily vitamin D supplement cut in half the risk of a respiratory infection." (1)

It is well understood that vitamin D is produced in the body by absorbing sunlight at certain times of the day in certain areas of the world – see our 3-part blog for details. This particular team of researchers, therefore, took their study to Ulaanbaatar, Mongolia, since the risk of vitamin D deficiency is very high in that area of the world, and especially during the winter. This is true in all northern areas of the world, including Nebraska where we live. Their study was conducted on school children who were determined to have low blood levels of 25-hydroxyvitamin D (25OHD), which is the gold standard for measuring vitamin D status in the body. That being said, these results are to be assumed to only apply to those children who are already deficient in this vitamin.


Although vitamin D is already known to be beneficial for bone health and many other issues as detailed in our original blogs, in this study, the researchers were attempting to compare the number of winter respiratory infections of those children who received daily supplementation of vitamin D through locally produced milk as compared to the control group who received the same milk, but without the vitamin D supplementation. This was a blind study in that  it would not be possible to detect which milk contained the supplement and which didn’t so that children, teachers, and local researchers could not tell which group received vitamin D.


Based on reports from their parents, the children receiving vitamin D had about half the incidence of respiratory infections than the control group had. Obviously, this is significant and something easily remedied with inexpensive vitamin D3 supplements readily available. The researchers used 300 IU daily as their dosage. Many doctors and clinical nutritionists are recommending much higher doses especially in the adult population. It would be important to have your levels checked before the fall flu season hits so you can begin to get you and your children’s vitamin D levels up to recommended levels. The U. S. Institute of Medicine raised their recommended daily dose for children to 400 IU, but some health professionals recommend doses as high as 1,000 IU for children who are risk. Again, it would be important to have your levels checked now to allow time to increase your levels. It is also recommended that if you begin supplementation with vitamin D, that you continue to have your levels monitored by your doctor.

Thanks for listening!



(1) Carlos A. Camargo Jr, Davaasambuu Ganmaa, A. Lindsay Frazier, Franca F. Kirchberg, Jennifer J. Stuart, Ken Kleinman, Nyamjav Sumberzul, and Janet W. Rich-Edwards. Randomized Trial of Vitamin D Supplementation and Risk of Acute Respiratory Tract Infection in Mongolia. Pediatrics, August 20, 2012