Everyone's bones lose density after age 40. In women, menopause accelerates the loss, especially if they're thin or small-boned, have red or blond hair or freckles, are of Oriental or northern European descent, or have never had any children. Smoking, a sedentary life, taking corticosteroids, and eating too few calcium-containing foods also increase the risk. And the earlier you reach menopause, the higher the risk. (Women who have a family history of osteoporosis, hyperthyroidism, hyperparathyroidism, and certain forms of bone cancer are also at risk.)

To prevent or slow osteoporosis, take these steps now.

• Be sure your diet includes a minimum of 1,000 milligrams a day of calcium (if you're
  premenopausal) or 1,500 milligrams a day (if you're postmenopausal). As mentioned in Tip 112 in chapter 4, Eating for Better Health, high-calcium foods include non-fat and low-fat dairy products and soft-boned fish like salmon and sardines and calcium-fortified foods such as some orange juices and cereal. Beans and bean sprouts, soybean curd, broccoli, kale, and sunflower seeds contain small amounts of calcium, too. Avoid supplements derived from dolomite or bone meal, however, and don't exceed 1,500 milligrams of calcium per day.
  
• Cut back on sodium and salt.
  
• Begin a program of regular, weight-bearing exercise like walking, jogging, biking, or low-
  impact or nonimpact aerobics.
  
• Ask your doctor about estrogen replacement therapy (ERT), which can prevent osteoporosis and other side effects of menopause (see the following tip).