Twin supplement study

Researchers invited 20 pairs of 9-to-13-year-old female, identical twins into a study on how calcium and vitamin D supplements affect bone mass and strength in young girls. One twin out of each pair was randomly selected to take a daily supplement containing 800 mg of calcium and 400 IU of vitamin D. The other twin received a placebo pill (no calcium or vitamin D).

The study was blinded, meaning none of the girls knew which pill she was taking. All of the girls were tested before and after the study to determine the density and amount of bone in arms and legs.

After six months, compared with the group of twins receiving the placebo, the girls taking 800 mg of calcium and 400 IU of vitamin D daily experienced:

• Greater gains in bone density
• Larger increases in the cortical bone area, which is the outer part of our bones and provides structural support for the body and protects organs
• Greater improvements in measures of bone strength for both arm and leg bones

Building strong bones

This study suggests that a daily calcium and vitamin D supplement can improve bone mass and strength in young girls. Use the following tips for safe use of calcium and vitamin D, and to make sure you enhance bone building in your kids.

• Dial the doctor or dietitian. Consult with a dietitian to figure out if your child needs a supplement of bone-building nutrients. Many young girls do not get adequate calcium and vitamin D from diet alone, but some get plenty without supplements. And always let your doctor know if you plan to add supplements to your child’s diet.
• Encourage activity. Weight-bearing activity, such as regular walking, playing, skipping, hopping and running around the playground can help build strong bones in kids.
• Make food count. Make sure bone-healthy foods, such as dark green leafy vegetables, fatty fish (for vitamin D), and dairy products, are a part of your child’s diet.
• Cut the cola. Many teen girls drink diet or regular soda every day. These products provide no calcium and may even spur bone loss due to their high phosphorus content and acidity. Encourage your child to drink water or milk instead.

(Osteoporos Int 2011;22:489–98)