Calcium is important to your body in many ways—from your bones to your heart to your nerves, muscles, and blood.

Calcium is essential for men and women of all ages -- infants, children, teens and adults. Everyone needs calcium, before birth and throughout life. Children and teenagers need calcium to develop strong bones and teeth; adults need it to maintain a strong skeleton.

Your body takes calcium from the foods you eat, but if you’re not getting enough calcium, your body will withdraw the mineral from your bones.

The Dietary Reference intakes recommended by the National Academy of Sciences vary with age and gender. Infants and toddlers (1 to 3 years) need 700 milligrams per day; children 4 to 8 years need 1,000 milligrams per day; older children and teens (9 to 18 years) need 1,300 milligrams per day; adults ages 19 to 50 need 1,000 milligrams per day; and older adults (51 and older) need 1,200 milligrams per day. Also, pregnant and nursing mothers under the age of 19 will need 1,300 milligrams per day; pregnant and nursing mothers 19 and older need 1,000 milligrams per day. Adequate amounts of vitamin D are required for your body to absorb calcium from food.

During these years, nearly half of adult bone mass is formed. According to the National Academy of Sciences, adolescents in this age group need 1,300 milligrams of calcium each day.

Walking, jogging, and aerobic dance are good for building strong bones because they are considered weight-bearing exercises. Swimming and bicycling are good for your cardiovascular health, but are not weight-bearing exercises.

You can find calcium in many foods, not just dairy products like milk, cheese, and yogurt. Green, leafy vegetables such as broccoli and collard greens are good sources of calcium. Tofu made with calcium sulfate is also a good source, as are canned sardines and salmon, if the soft bones are eaten.

You can minimize bone loss that occurs after this age by getting adequate calcium and vitamin D, by exercising, and by avoiding tobacco and excessive alcohol use.

That’s why it’s important that children get enough calcium, particularly between the ages of 9 and 18.

But you can take steps to cut back on the loss of bone mass by getting enough calcium in your diet and by incorporating weight-bearing exercise into your lifestyle.