Vitamin D traditionally plays a role in bone health, promoting calcium absorption in the gut and regulating calcium and phosphate levels to allow normal bone mineralization. Over the past two decades, scientists have begun to realize that vitamin D has many other functions in the body, such as modulation of cell growth, improved immune function and reduction of inflammation.
Vitamin D research continues to be published on a daily basis, expanding our understanding of the importance of this unique vitamin in various health conditions. However, a disconnect between research and clinical practice exists. It takes years and sometimes even decades for research to become integrated into practice.
A recent study aimed to determine whether the increased amount of available research on vitamin D has coincided with an increase in vitamin D status among individuals in the U.S. The researchers used data from the National Health and Nutrition Examination Surveys (NHANES) to examine the trends of vitamin D status from 1988 to 2010. A total of 51,146 participants were examined. A dietary supplement questionnaire was used to collect information regarding the type, frequency, duration, serving size, quantity and dose of supplementation. All participants had their vitamin D status measured.
The average vitamin D status was 24.92 ng/ml in 1988 and 26.84 ng/ml in 2010. The researchers found that average vitamin D status showed no time trend from 1988-2006. Although, a significant increase in vitamin D status of 2.5 ng/ml was observed in the 2007-2010 surveys (p < 0.0001).
The researchers explained the reasoning for the increase in vitamin D status,
“This increase appeared to be related to vitamin D supplement use…Compared with surveys conducted during 1988-2006, the mean 25(OH)D in 2007-2010 was significantly higher in vitamin D supplement users by 3.46 ng/ml (p < 0.0001) but not in nonusers (p = 0.09).”
The researchers also found that there were 10% more individuals taking > 600 IU daily in 2010 compared to 1988 (p < 0.0001).
A secondary analysis indicated that younger participants (between the ages of 12-19 years) were least likely of all age groups to take vitamin D supplements. Whereas, older individuals (> 40 years of age), females and non-Hispanic whites were significantly more likely to take the higher dose supplements (> 600 IU).
The researchers concluded,
“An accurate method for measuring 25(OH)D showed stable mean concentrations in the US population (1988-2006) and recent modest increases (2007-2010).”
Despite the abundance of new research illustrating the benefits of vitamin D, the average vitamin D status of the US population remained deficient (26.84 ng/ml). The study depicts the need for increased awareness and dissemination of vitamin D information among the general public. The Vitamin D Council hopes to help this process by acting as a liaison between the researchers and the public. We ask you to do the same. Tell your friends, family, coworkers and neighbors about the importance of maintaining a healthy vitamin D status, which typically requires a daily dose of 5000 IU for the average adult. Together, we can make a difference!
Tovey, A & Cannell, JJ. Has vitamin D status of the US population changed over two decades? The Vitamin D Council Blog & Newsletter, 2016.
Schleicher R. et al. The vitamin D status of the US population from 1988 to 2010 using standardized serum concentrations of 25-hydroxyvitamin D shows recent modest increases. American Journal of Clinical Nutrition, 2016.