How much calcium you need depends on your sex, age and risk for osteoporosis. Unfortunately. most only get about half, or 500 milligrams, from their diets. Getting enough calcium is especially important if you're a woman under age 30, because your body is still able to absorb and store calcium in your bones easily. Experts recommend 1,500 milligrams per day for teens, pregnant or breast-feeding women and older adults. This amount is especially important if you are an older adult, because your intestines don't absorb calcium as well.
Supplements vary widely in the amount of calcium they contain.
Supplements of calcium carbonate contain the highest amount of useful, or elemental, calcium. If you take a calcium supplement, be sure to take it with meals and drink six to eight glasses of water each day. Avoid Smoking People who smoke cigarettes have a greater risk of fracture than non-smokers. Smoking reduces bone mass. Smokers may have an increased risk because they often weigh five to 10 pounds less than non-smokers.