Calcium and osteoporosis

Osteoporosis is a crippling disease that emerges as an important public health problem both in developed and developing countries including Brazil. The clinical condition is characterized mainly by loss of bone mineral mass in later life as the net result of complex physiological and environmental interacting factors during lifetime. Calcium intake appears as an obvious nutritional factor in the prevention of osteoporosis but its contribution is still not well established particularly when populations with different habitual levels of calcium intake are compared. In this section, we examine the role of calcium intake as affecting bone mineral density at different stages of development and with aging, with special attention to the possible stress on bone mass due to pregnancy and lactation. Nutritional studies demonstrate that, in general, adequate calcium intake during lifetime contributes to decrease the risk of osteoporosis. However, the long term effects on bone health of sub-adequate, but not very low, habitual calcium intakes during highly demanding physiological periods such as adolescence, pregnancy and lactation, are still largely unknown. Sub-adequate calcium intakes are probably common in Brazil.