Calcium—Good for Teen Growth and Bone Building

Healthnotes Newswire (December 8, 2005)—Teenage boys can increase their bone-mineral content and their height by taking a calcium supplement, according to the Journal of Clinical Endocrinology and Metabolism (2005;90:3153–61).

Osteoporosis is a major contributor to health problems in older people. The severely low bone density that characterizes osteoporosis increases the risk of fractures, which can lead to immobility and complicated recovery that can even result in death. Osteoporosis prevention has a two-pronged approach: maximizing the bone density at the time in life when it reaches its peak (about 25 years old) and minimizing bone loss in later life. A number of nutrients can influence bone density by stimulating proper use of calcium by the body; however, adequate calcium intake and exercise remain the cornerstones of osteoporosis prevention. Several studies have found that supplementing with calcium before and around the time of puberty can lead to increased bone-mineral density. Little is known about the effects of calcium supplementation in adolescents who are past puberty.

In the current study, 143 healthy boys between the ages of 16 and 18 were randomly assigned to take either a calcium supplement (500 mg twice per day in the form of calcium carbonate) or a placebo for 12 months. Bone-mineral status, height, and weight were measured at the beginning, middle, and end of the study. It was determined at the end of the study that overall compliance was about 59%; in the calcium group, the intake of supplemental calcium averaged 652 mg per day. Measurements taken at the middle and end of the study showed that the amount of mineral in the bones (bone-mineral content) increased significantly more in the boys taking calcium than in the boys not taking calcium; the difference was greater at the end of the study. In addition, the boys taking calcium grew significantly more in height than the boys who did not take calcium. This difference was 7 mm, or about 0.28 inches. Finally, when activity level was considered, the boys with a high activity level had more bone mass and increased their bone-mineral content more than boys with a low activity level.

The results of this study show that calcium supplementation can lead to an increase in bone-mineral content and an increase in growth in height in adolescent boys. They also add to the evidence that exercise is beneficial for bone-building during adolescence. In a previous study, adolescent girls who were past puberty (ages 16 to 18) experienced an increase in bone-mineral density but did not increase in height more than girls who did not take calcium. Whether these changes in bone density will have a lasting impact on bone health later in life in either gender should be a topic of future research. Additional research should also focus on whether the short-term height gain seen in boys taking calcium will result in them being taller once they reach their maximum height.