Calcium supplementation and bone loss: a review of controlled clinical trials.

The responsiveness of postmenopausal women to supplementation with calcium appears to depend on their menopausal age. In women who are within the first 5 y of menopause, bone loss from the radius is attenuated but not arrested by added calcium. The maximal effect appears to occur with supplement dosages of approximately 1000 mg elemental Ca/d. In contrast, the spine is unresponsive to supplementation with calcium even at higher doses in early postmenopausal women. In late postmenopausal women, bone loss from the radius is attenuated by increased calcium intake. Loss from the spine can be retarded by increasing calcium intake to the current recommended dietary allowance in older women with low usual calcium diets. The effect of supplementation with higher doses of calcium in this segment of the population is unknown. Finally, the effect of added calcium on hip density of postmenopausal women is not yet established.