Dairy calcium is related to changes in body composition during a two-year exercise intervention in young women

Objective: Relationships between micronutrients and dairy product intake and changes in body weight and composition over two years were investigated. Design: Two year prospective non-concurrent analysis of the effect of calcium intake on changes in body composition during a two year exercise intervention. Subjects: 54 normal weight young women, 18 to 31 years of age. Measures of Outcome: Mean intakes of nutrients of interest were determined from three-day diet records completed at baseline and every six months for two years. The change in total body weight and body composition (assessed by dual x-ray absorptiometry) from baseline to two years was also determined. Results: Total calcium/kilocalories and vitamin A together predicted (negatively and positively, respectively) changes in body weight (R-2 = 0.19) and body fat (R-2 = 0.27). Further, there was an interaction of calcium and energy intake in predicting changes in body weight, such that, only at lower energy intakes, calcium intake (not adjusted for energy) predicted changes in body weight. Conclusions: Regardless of exercise group assignment, calcium adjusted for energy intake had a negative relationship and vitamin A intake a positive relationship with two year changes in total body weight and body fat in young women aged 18 to 31 years. Thus, subjects with high calcium intake, corrected by total energy intake, and lower vitamin A intake gained less weight and body fat over two years in this randomized exercise intervention trial.