The relationship of dietary calcium to the maintenance of skeletal integrity in man-an interface of endocrinology and nutrition

Abstract

Calcium restriction reliably produces osteoporosis in animals, but the impact of dietary calcium on age-related bone loss in man is controversial. The opinion that calcium intake is not clearly related to bone mass or to osteoporosis is well-entrenched in the nutrition literature, and has been influential in setting recommended intakes for the American public. This position rests on the poor correlation between habitual calcium intake and the incidence of osteoporosis in some non-Western countries, and on demonstrations that young men can achieve calcium balance on low intakes. However, such data neglect a variety of factors which determine calcium nutriture. These include the efficiency of mineral utilization, gonadal status, and the effect of dietary protein. It has recently been demonstrated that calcium requirements increase during adult life in women. This increase is attributable in large measure, but not completely, to estrogen deprivation associated with the menopause. In addition, the American diet is abundant in protein, a situation which may be deleterious to bone. Based on the evidence currently available, it is reasonable to propose that adolescent and young women consume one gram of calcium daily, and that this intake be increased to 1500 mg to the time of menopause.