Your best friend during 'cold and flu season' may just be Vitamin D!!

Wednesday, December 22, 2010

By Laura Firetag, ND Student, Bastyr University

It is that time of year again!!

It’s time for family, friends, celebration and the yearly assault on our immune systems which can result in sneezing, coughing and misery instead of fun and joy.

While it is impossible to get a vaccine that is specific for every cold and flu virus, it is possible to strengthen our own innate defenses. I put together a presentation about Vitamin D and the immune system for my immunology class this summer and found that study after study is showing that there is a correlation between higher serum levels of Vitamin D and a lower risk of succumbing to a viral infection. This correlation makes logical sense since the ‘cold and flu season’ occurs when there is both less sunlight available and less skin exposed to the sunlight that is available. There is also plenty of documentation that ‘influenza epidemics occur simultaneously at the same latitudes across the globe.’ The same latitudes are always the same distance from the sun and therefore receive the same amount and intensity of light rays throughout the year. When there is more sun, our serum 25-hydroxyvitamin D levels are higher. When there is less sun during the fall and winter months, our serum 25-hydroxyvitamin D levels decrease and the cold and flu season begins.

An impressive study entitled ‘Serum 25-Hydroxyvitamin D and the Incidence of Acute Viral Respiratory Tract Infections in Healthy Adults’ was published just days after my presentation in June. The study is a prospective cohort study that measured the serum vitamin D level and incidence of acute viral respiratory tract infection in 198 adults. Serum Vitamin D concentrations of 38 ng/ml or more were not only associated with a significant (p<0.0001) two-fold reduction in the risk of developing acute respiratory tract infections but also a marked reduction in the percentages of days ill. The study also revealed that light skin pigmentation, lean body mass, and supplementation with vitamin D were found to correlate with higher concentrations of 25-hydroxyvitamin D meaning that dark skinned and obese individuals will probably need to supplement with higher levels of Vitamin D to maintain adequate serum levels. The researchers concluded that ‘maintenance of a 25-hydroxyvitamin D serum concentration of 38 ng/ml or higher should significantly reduce the incidence of acute viral respiratory tract infections and the burden of illness caused thereby, at least during the fall and winter in temperate zones.’

The recently released 2011 “Report on Dietary Reference Intakes for Calcium and Vitamin D” from the Institute of Medicine recommends that individuals maintain a serum 25-hydroxyvitamin D level of 20 ng/ml since they determined that higher serum levels were not consistently associated with greater benefit. This recommendation and the results of so many studies that definitively show a benefit from higher serum levels guarantee that Vitamin D will continue to be a topic of great interest and debate for many years. My primary care physician, who is an MD in Charleston, SC, recommends that I maintain a serum 25-hydroxyvitamin D level of 80 ng/ml. As you can see, there is a huge range of opinions on this clinically significant subject. Hopefully, high quality gold-standard research will provide clear answers about both adequate daily dosage and ideal serum levels in the future.

I hope you have a Happy and Healthy holiday season!!!

Sabetta JR, DePetrillo P, Cipriani RJ, Smardin J, Burns LA, et al. (2010) Serum 25-Hydroxyvitamin D and the Incidence of Acute Viral Respiratory Tract

Infections in Healthy Adults. PLoS ONE 5(6): e11088. doi:10.1371/journal.pone.0011088

posted by Innate Response at

7:48 AM

Your best friend during 'cold and flu season' may just be Vitamin D!!

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