10.01.08
Despite considerable progress in research to understand the health effects of vitamin D, experts recently convened by the National Institutes of Health (NIH) to review the available data found major gaps in the evidence. The data are strongest in the area of bone health among elderly men and post-menopausal women, suggesting that increased vitamin D intake can improve bone health and prevent falls. However, for other age groups and health issues, it is too early to say conclusively whether more vitamin D might be beneficial. An in-depth review of current research on the health effects of vitamin D was published as the proceedings of the NIH conference, “Vitamin D and Health in the 21st Century: An Update,” which appeared in an August 2008 supplement to the American Journal of Clinical Nutrition.
Conference participants identified several limitations of existing evidence on vitamin D, including: many studies have failed to control for factors that could confuse study findings, such as diet, baseline vitamin D status, age, disease, season (as relevant to sun exposure) and physical activity; few studies have examined the effects of vitamin D independent of calcium or other nutrients; reliable data on the vitamin D content of foods are not available; existing laboratory tests used to measure vitamin D levels in blood vary widely; and research has not identified vitamin D levels needed to achieve desired health outcomes in people at various life and reproductive stages.
Conference participants identified several limitations of existing evidence on vitamin D, including: many studies have failed to control for factors that could confuse study findings, such as diet, baseline vitamin D status, age, disease, season (as relevant to sun exposure) and physical activity; few studies have examined the effects of vitamin D independent of calcium or other nutrients; reliable data on the vitamin D content of foods are not available; existing laboratory tests used to measure vitamin D levels in blood vary widely; and research has not identified vitamin D levels needed to achieve desired health outcomes in people at various life and reproductive stages.