A randomized, placebo-controlled study published in the Journal of Bone and Mineral Research (May 2008; 23(5):741–749) examined the relationship between calcium and vitamin D supplementation and the incidence of stress fractures during military training.
The study included more than 5,000 female U.S. Navy recruits undergoing eight weeks of basic training. Participants were randomly assigned to receive either a daily supplement containing 2,000 mg of calcium and 800 IU of vitamin D, or a placebo, for the duration of training.
During the training period, 309 recruits developed stress fractures. The incidence of stress fractures was approximately 20% lower among those receiving calcium and vitamin D supplementation compared with the placebo group.
The authors concluded that supplementation with calcium and vitamin D was associated with a reduced risk of stress fractures in this physically demanding training environment.
