It is estimated that 10 million Americans have osteoporosis , a condition characterized by weak bones that break easily. While osteoporosis most often affects older adults, the best time to prevent it is during childhood. People reach their peak bone mass (the time when their bones are the strongest) around age 30, and at least 90% of peak bone mass is formed by age 18. Not optimizing bone health during these formative years may increase the risk of osteoporosis later in life. Studies have shown that physical activity interventions and calcium supplementation can increase bone density, but it is unclear whether this effect can be maintained over time.

A new report published April 19, 2006 in The Cochrane Database of Systematic Reviews found that while calcium supplements resulted in small increases in bone mineral density in children’s arms, these increases were unlikely to significantly decrease lifetime fracture risk.

About the Study

Researchers identified 19 studies that compared the effects of calcium supplementation with placebo on children’s bone health. These trials included 2,859 children ages 3-18 years. About half of the children were randomly assigned to receive daily calcium supplementation and the other half were assigned to receive a placebo. The calcium supplements ranged from 300 to 1,200 milligrams of calcium daily, and were administered for 8.5 months to seven years. The researchers performed bone mineral density tests to measure bone strength in the hip, spine, arm, and total body overall.

Calcium supplementation had no effect on bone density of the hip and spine, but it was associated with small increases in the total body and arm. Once the children stopped taking the supplements, however, the increases only remained in the arm. The results were not affected by calcium dose, sex, ethnicity, physical activity, or stage of puberty.

This study was limited because it did not follow the children into adulthood to see who actually experienced fractures, which would have produced more reliable results. Also, the results cannot be applied to children with conditions that affect bone health, since these children were not included in the study.

How Does This Affect You?

These findings suggest that calcium supplements may not be the best way to improve bone health in healthy children. Although supplementation was associated with increases in bone density in the arm, the researchers point out that the increases were so small that they were unlikely to result in a clinically significant decrease in fracture risk.

If you are looking for ways to improve your child’s bone health, a daily calcium supplement may not be the magic bullet. But ensuring that your child is getting proper nutrition and plenty of bone-building physical activity can still help build stronger bones. Children should eat plenty of foods that are rich in calcium and vitamin D, especially milk and other dairy products (e.g., yogurt, cheese). In addition, regular weight-bearing activities (e.g., walking, running, dancing, tennis, basketball, gymnastics, soccer) can help to build strong bones.