Most Americans don't consume enough calcium to protect themselves from the bone-weakening disease osteoporosis, the National Academy of Science warned last summer when it increased the recommended intake of the mineral to between 1,000 and 1,300 milligrams per day.
Exercise also is essential for building bone in youth and preventing bone loss with age.
Vitamin D also is important because it aids the absorptionof calcium, notes Nelson, who says good sources of vitamin D are fortified dairy products and 15 minutes of exposure to sunlight daily. However, the skin can't manufacture vitamin D in people wearing sunscreen or during winter months in latitudes above 42 degrees north, such as Boston or Milwaukee. Weight-bearing activities are those in which you work your bones and muscles against gravity. Walking, stair climbing, dancing, running, and racket sports are all weight-bearing activities with differing degrees of impact. In general, the higher the impact, the more the activity strengthens bones.