Dairy calcium intake, serum vitamin D, and successful weight loss

Background The role 01 dairy calcium intake and scrum vitamin D concentrations in weight loss is controversial Objective The objective was to assess the association of dairy calcium intake and serum vitamin D with weight loss Design We analyzed data from participants in the 2 y Dietary Intervention Randomized Controlled Trial (DIRECT) [n = 322 mean body mass index (BMI in kg/m(2)) 31 mean age 52 y] A representative sample (n = 126) was followed for 6 mo for serum vitamin D changes Results Baseline serum 25 hydroxyvitamin D [25(OH)D] concentrations decreased significantly across the tertiles of baseline BMI (25 6 +/- 8 0 24 1 +/- 8 9 and 22 9 +/- 6 8 ng/mL respectively P for trend = 0 02) Baseline concentrations of vitamin D and dairy calcium intake were not associated with subsequent weight loss How ever in repeated-measures models adjusted for age sex baseline BMI total tat intake and diet group assignment higher 6 mo tertile levels of dairy calcium intake (median for tertiles 156 5 358 0 and 582 9 mg/d respectively) and serum 25(OH)D (14 5 21 2 and 30 2 ng/mL respectively) were associated with increased weight loss across the 2 y intervention (-3 3 -3 5 and -5 3 kg respectively for dairy calcium P = 0 043 -3 1 -3 8, and -5 6 kg respectively for vitamin D, P = 0 013) In a multivariate logistic regression adjusted simultaneously for age sex baseline BMI total fat intake diet group vitamin D concentration and dairy calcium an increase of 1 SD in dairy calcium intake increased the likelihood of weight loss of >4 5 kg in the preceding 6 mo [odds ratio (OR) 1 45 P = 0 046] A similir increase was seen for serum 25(OH)D at the 6 mo point (OR 1 7 P = 0 009) Conclusion Our study suggests that both higher dairy calcium in take and increased serum vitamin D are related to greater diet-induced weight loss This trial was registered at clinicaltrials gov as NCT00160108 Am J Clin Nutr 2010 92 1017-22