A study published March 2005 online in Journal of Clinical Endocrinology & Metabolism found that boys who received calcium supplements had greater bone mineral content and were taller than those who did not receive the supplements. Improving bone mineral content early in life is believed to help reduce osteoporotic fractures later on.
Researchers at the Medical Research Council Human Nutrition Research, Elsie Widdowsom Laboratory in Cambridge, England, randomzied 153 boys ages 16 to 18 to receive 500 milligrams calcium twice per day in the form of calcium carbonate, or a placebo for 13 months. Additionally, participants were grouped according to whether their activity level was high or low. Bone mineral content, bone area, lean and fat mass, height, and weight were measured before, during and following the treatment period.
Although both groups experienced increases in height, weight, lean and fat mass and most bone measurements over the course of the study, the group receiving calcium was found to have a significant increase in height, lean mass and bone mineral content of the whole body, lumbar spine and and hip compared to the boys who received a placebo. Adjustment for bone area and height lessened the increase in bone mineral content, which suggested that calcium's effect was accomplished through an effect on growth. Physical activity level appeared to increase the effect of calcium supplementation on bone mineral content only in an area of the upper leg bone.
The authors conclude that "calcium carbonate supplementation of adolescent boys increased skeletal growth, resulting in greater stature and bone mineral acquisition. Follow-up studies will determine whether this reflects a change in the tempo of growth or an effect on skeletal size that persists into adulthood."
Journal of Clinical Endocrinology & Metabolism, March 8 2005