Milk and milk products are rich sources of calcium and in Canada fluid milk is fortified with vitamin D. Both calcium and vitamin D are acknowledged for their role in bone health and more recently are implicated in growth and body composition. In healthy children 2-5 y of age (n=508, Montreal), milk and milk products accounted for the majority of calcium and vitamin D intakes.

Children in the highest tertile for fluid milk intake had greater plasma 25-hydroxyvitamin D (25OHD) concentrations than the lowest (78.3±1.4 vs 69.4±1.4 nmol/L, p=0.02). Subsequently, in children 2-8 y of age (n=51, Montreal), a 6-month intervention with vitamin D-fortified (300 IU) yogurt beverage and cheese enhanced percent change in whole body lean mass in the intervention group (8.4 vs 5.9%). In healthy children 6-8.5 y of age (n = 78, Montreal) with weight issues, increasing milk and milk products to 4 servings/day and physical activity over 1 y improved whole body and lateral lumbar spine bone mineral density. Body composition was improved as well. In adolescent females 14-18 y of age (n=64, Montreal), increasing milk and milk product intake from < 2 to 4 servings/day over 1 y through motivational interviewing techniques enhanced protein, calcium and vitamin D intakes, and increased whole body bone mineral accretion (126±120 vs 58±83 g/y, p<0.05). 

Total energy intake, and activity were not altered. Lastly, a meta-analysis of 17 trials of milk and milk product interventions in children (6-18 y), suggests greater increases in body weight and lean mass, and attenuated gain in body fat percentage compared with control. This series of studies in young children and adolescents collectively demonstrate that healthy intakes of calcium and vitamin D from food sources support healthy growth, body composition and bone mineral accretion.