Bone mineral density of adolescents as affected by calcium intake through milk and milk products

Elevated levels of milk and milk products were incorporated into the diet o f 15-16 yr old adolescents with subaverage bone mineral density in order to obtain a daily calcium intake of about 1200 mg. The bone mineral density w as significantly improved by about 50% when compared with control subjects without such a dietary intervention (+0.053 vs +0.036 g cm(-2)). The rate o f increase, however, was significantly lower for girls than for boys (also by about 50%. +0.019 vs +0038 g cm(-2)), possibly due to the more advanced bodily development of girls at this age. As the rate of increase of the bon e mineral density is significantly decreasing for adolescents of this age g roup (20-35% in boys 16 yr of age when compared with 15 yr old ones, and 40 -50% in girls), it can be predicted that such a dietary intervention starti ng at 15 yr of age will lead to an average level of the bone mineral values after 3-4 yr and even to an optimum level after 6-7 yr in boys with an ori ginally subaverage level. However, such improvement is no longer feasible f or girls at this age. The concentration of osteocalcin and parathyroid horm one as well as the activity of alkaline phosphatase in blood serum indicate d that the higher than proportional increase of bone mineral density in the intervention group can be attributed to a decreased bone turnover which wa s caused by an increased intake of calcium through milk and dairy products. (C) 1999 Elsevier Science Ltd. All rights reserved.