Vitamin D, aging, and the 2005 Dietary Guidelines for Americans.

The 2005 Dietary Guidelines for Americans recommend that older adults, people with dark skin, and those exposed to insufficient ultraviolet radiation (i.e., sunlight) consume extra vitamin D from vitamin D-fortified foods and/or supplements. Individuals in these high-risk groups should consume 25 microg (1000 IU) of vitamin D daily to maintain adequate blood concentrations of 25-hydroxyvitamin D, the biomarker for vitamin D status. This review considers recommendations for vitamin D-rich foods and dietary supplements, as well as specific problems with self-prescribing sun exposure or artificial sources of ultraviolet radiation to meet the vitamin D recommendations for older people.