The role of nutrition in osteoporosis.

Osteoporosis-related bone fractures are a significant cause of mortality and morbidity, with women being particularly affected. Osteoporosis is a condition of bone fragility resulting from micro-architectural deterioration and decreased bone mass; adult bone mass depends upon the peak attained and the rate of subsequent loss; each depends on the interaction of genetic, hormonal, environmental and nutritional factors. An adequate supply of calcium is essential to attain maximum bone mass, and adult intakes below about 500 mg/day may predispose to low bone mass. Supplementation with calcium may conserve bone at some skeletal sites, but whether this translates into reduced fracture rates is not clear. Chronically low intakes of vitamin D--and possibly magnesium, boron, fluoride and vitamins K, B12, B6 and folic acid (particularly if co-existing)--may pre-dispose to osteoporosis. Similarly, chronically high intakes of protein, sodium chloride, alcohol and caffeine may also adversely affect bone health. The typical Western diet (high in protein, salt and refined, processed foods) combined with an increasing sedentary lifestyle may contribute to the increasing incidence of osteoporosis in the elderly.