Efficacy of a Once Daily Calcium and Vitamin D Fortified Food Product to Improve Bone Microarchitecture

Stress fractures may affect up to 2-5% of male and 8-21% of female Soldiers during training, resulting in attrition in up to 60% of affected personnel. A recent report indicates that supplemental calcium (2000mg) and vitamin D (800-1000IU) stabilizes PTH, increases tibia volumetric bone mineral density in male and female recruits undergoing Army BCT, and reduces stress fracture incidence by up to 20% in female Nacy recruits. Bone macroarchitecture has been measured in response to basic training however, the resolution of standard peripheral quantitative computed tomography (pQCT) is insufficient for assessment of microarchitectural changes, which may underlie the pathophysiology of stress fracture. With the use of HRpQCT this study will allow the investigators to evaluate microarchitectural changes within the bone tissue and assess the efficacy of a moderate daily dose of calcium and vitamin D to support bone health during BCT.