Diet
The Surgeon General released a report about osteoporosis in 2004 and recommended that all people should eat adequate amounts of calcium. The calcium can come from the food (especially dairy products, tofu, some green vegetables and bones of fish), fortified foods such as orange juice or cereal or from supplements. Adults need 1200mg of calcium each day to help promote strong bones.
Vitamin D is also important. This is not found in very many foods but is added to dairy products in the USA. Most people will also need to take vitamin pills to get an adequate amount of vitamin D. The current "official" recommendation is 400 units a day but many doctors think that older men and women should get at least 800 units a day.
Thin persons are much more likely to get osteoporosis. In fact, obesity is good for the bones (although it has other health problems). The "body mass index" is a way of telling if a person is too thin for his or her height. If the body mass index is lower than 20, eating extra calories to gain weight would be beneficial. The upper limit of normal body mass index is 25. The body mass index can be calculated using the on-line calculator from the National Institutes of Health.