Vitamin D: Bone Health and Beyond

Abstract

The “sunshine vitamin” or vitamin D has long been known to play an important role in the promotion and maintenance of strong, healthy bones. Vitamin D status has generally not been a focus of public health concern for many years; reasons include our endogenous manufacture of vitamin D in the skin, fortification of some foods, and the rarity of overt childhood vitamin D deficiency (“rickets”) in the United States and Europe. However, recent evidence suggests that the vitamin D status of many Americans may, in fact, be reason for significant concern. And it is not just bone health that is affected. Research indicates that vitamin D has many nonskeletal functions. Epidemiologic associations have linked vitamin D with the risk of developing a host of health conditions, including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, hypertension, cardiovascular disease, some cancers, and forms of depression. At the same time, questions remain about the risks and benefits of exposure to sunlight, supplement use, and food fortification. Worldwide vitamin D insufficiency has been termed a “pandemic” by some experts. Yet most experts agree that, to date, insufficient data exist to support reliable assessment and supplementation guidelines for most subpopulations. This article describes the state of knowledge about vitamin D, clinical implications, screening criteria, dietary and supplemental sources, and recommendations.