title: What is the optimal dietary intake of vitamin D for reducing fracture risk?
abstract: Vitamin D has long been known to be important for bone health, but there is currently no consensus on the amount of vitamin D needed or how it varies with age, race/ethnicity, body size, absorption efficiency, season, and other factors. This review describes the effects of vitamin D on calcium absorption, parathyroid hormone levels, and changes in bone mineral density briefly and focuses in more detail on the results and interpretation of double-blind randomized controlled trials with fracture outcomes in older adults. Based on these trials, 400 IU/day, bringing 25-hydroxyvitamin D (25OHD) levels to 60-65 nmol/L, is not effective at lowering fracture risk in community-dwelling elders or in elders with prior fractures. Several large trials indicate that doses in the range of 700-1,000 IU/day can lower fracture risk by ~20 %. From these trials, it appears that a 25OHD level of 65 nmol/L is needed to reduce nonvertebral fracture risk and 75 nmol/L may be needed to lower hip fracture risk. Trials testing additional doses of vitamin D in different segments of the population are needed.
authors.affiliation: Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, 711 Washington St., Boston, MA 02111, USA. bess.dawson-hughes@tufts.edu
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
mesh_terms: D004032:Diet; D050723:Fractures, Bone / Q000517:prevention & control*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D014807:Vitamin D