According to a U.S. survey, individuals with low vitamin D blood levels have a higher risk of nose and throat infections.
In a secondary analysis of the Third National Health and Nutrition Examination Survey (NHANES), a survey of the U.S. population, found that individuals with low blood levels of a vitamin D marker (25-hydroxyvitamin D) were also more likely to have an upper respiratory tract infection (URTI). Specifically, the analysis found that compared to those with levels greater than 30 nanograms/milliliter (ng/ml), individuals with less than 10 ng/mL had a 36% higher risk of having a recent URTI; those with 10–<30 ng/mL had a 24% higher risk (1).
In recent years, vitamin D deficiency has reemerged, resulting in the resurfacing of diseases such as rickets in children. According to the Dietary Guidelines for Americans 2005, “Older adults, people with dark skin, and people exposed to insufficient ultraviolet band radiation (i.e., sunlight) should consume extra vitamin D from vitamin D-fortified foods and/or supplements.”
The researchers commented that the evidence supporting the benefits of vitamin D continues to build. Given that vitamin D levels are relatively low in most foods and there are serious risks associated with excessive sun exposure, dietary supplements can be an effective alternative for achieving a sufficient intake. However, this study on its own does not mean that higher vitamin D intake will ensure prevention of upper respiratory tract infection.