Objectives: To investigate the effects of calcium and vitamin D supplementation in fortified milk on physical development in Chinese school girls aged 10 - 12 years.
Methods: A non-randomized, double-blind intervention trial was carried out at nine primary schools of Beijing for two years. Seven hundred and fifty-seven girls (with an average age of 10.1 years) were recruited from nine primary schools in Beijing, China. They were divided into three trial groups, a control group (n = 259) having regular diet without milk supplementation, Group 1 (n = 238) having regular diet supplemented with 144 ml/d of calcium-fortified milk, and Group 2 (n = 260) having regular diet supplemented with 144 ml/d of calcium and vitamin D-fortified milk. Data of dietary intake and physical activities were collected by questionnaire, and height, weight, sitting height and knee height were measured before, during and after intervention.
Results: Two years after intervention, the percentage increases in height and weight were significantly greater in Groups 1 and 2 than those in control group (9.52%, 9.26% and 8.59% in height, and 34.53%, 35.38% and 30.91% in weight, respectively). The percentage increase of sitting height was greater in Group 1 than those in Group 2, and then than that in control group (9.21%, 8.58% and 7.87%, respectively). The percentage increase of knee height was significantly greater in Group 1 than that in Group 2 and control group (9.00%, 8.37% and 8.44%, respectively).
Conclusion: Calcium and vitamin D-fortified milk supplementation could promote their physical development in girls aged 10 - 12 years.