Calcium is a mineral that helps bones stay strong. Our bodies continually remove small amounts of calcium from our bones and replace it with new calcium, a bone "remodeling" process. If the body removes more calcium from bones than it replaces, they slowly become weaker and more prone to breaking. Eating a diet rich in calcium allows the body to deposit calcium in bones so they stay strong.
Children and teens who eat calcium-rich foods build up stores of calcium in their bones that help them maintain strong bones for life. By getting lots of calcium when you're young, you can make sure your body doesn't have to take too much from your bones. Bones have their own "calcium bank account," so "depositing" as much calcium as possible during your tween and teen years will help you reach your peak bone mass. By the end of the teen years, the account "closes"―you can't add any more calcium to your bones. You can only maintain what is already stored to help your bones stay healthy.