In addition to calcium's role in strengthening the skeleton, emerging evidence indicates that the mineral might also lower the risk of colon cancer, reduce cholesterol and blood-pressure levels, ease premenstrual syndrome, and possibly aid weight loss. But even if you regularly consume the recommended three daily servings of dairy products-which typically contain around 200 to 400 milligrams of calcium each-it's still a challenge to get the amount of calcium we recommend: 1,000 mg for younger adults and 1,200 mg for those 50 and older. People with weakened bones should talk with their doctor about getting 1,500 mg daily.

Other good food sources are dark, leafy greens and calcium-fortified versions of orange juice, tofu, or other foods. Be cautious with supplements because large amounts of the mineral can block the absorption of other nutrients, cause kidney problems, and possibly increase the risk of prostate cancer.

Choose pills according to what is cheapest, is most palatable, or requires taking the fewest tablets. The type of compound does not significantly affect its absorbability, despite some manufacturers' claims. But do look for supplements labeled "USP Verified." They've been tested by the U.S. Pharmacopeia for purity and potency.