Vitamin D and the flu.

This just in from one of my vendors.

"Vitamin D has been in the news a great deal lately. Last year the Public Health Agency of Canada (PHAC) started a study investigating the role of vitamin D in severe seasonal influenza. With the recent outbreaks of swine flu, PHAC confirmed that it would be adapting this study to investigate the role of vitamin D in the protection against swine flu. PHAC will measure vitamin D levels in the blood of H1N1 patients and compare the blood levels with uninfected individuals. The rationale behind this study is based on earlier work in the 1940's that indicated mice on diets low in vitamin D were more susceptible to experimental swine flu infection than those with adequate vitamin D levels (Young, et al., Vitamin D intake and susceptibility of mice to experimental swine influenza virus inf ection. Proc Soc Exp Biol Med. 1949 Dec;72(3):695-7.) How vitamin D might protect against influenza infection is not fully understood. However, research suggests that vitamin D may induce the production of antimicrobial substances in the body that may possess neutralizing activity against a variety of infectious agents including influenza virus."

I run a 25-OH vitamin D on all of my patients. Although the "normal" range is 32-100, I personally prefer to see levels closer to 70 or 80, with 50 being bare minimum. Some physicians are just prescribing 2000 iu daily with the idea that everyone needs vitamin D but I've seen patients who are taking 5000 a day with levels of 30, and others taking 2000 a day with levels of 60 (for the record this is uncommon.) We tested our almost 3 year old and at the end of a long summer of days half naked in the sun with no sunscreen plus 1000 iu daily of vit D, and his blood level was only 32. It is best to get your levels checked.