Bone metabolism in postmenopausal women and effect of calcium intake on their fracture risk / 中华临床营养杂志

ABSTRACT

The rate of bone turnover in postmenopausal women accelerates and the newly formed osteoid is poorly mineralized, resulting in the loss of bone mineral content. Meanwhile, the requirement for calcium increases as more bone matrix needs to be mineralized. On the other hand, the reduction of serum estrogen level impairs the absorption of calcium in intestinal tract and the reabsorption in kidney, resulting in the decreased absorption and increased excretion of calcium. Therefore, sufficient calcium intake is critical for maintaining the bone structure in postmenopausal women. The reference intake of calcium differs greatly among different countries. In 2000, China established the adequate intake of calcium for Chinese women aged 50 years and older as 1000 mg/d. Diets provide the optimal source of calcium to prevent osteoporosis. Although calcium supplements have been demonstrated to be beneficial for the bone mineral density in postmenopausal women, its impact on fracture risk and cardiovascular diseases remains controversial. Available evidences suggest that calcium supplements combined with vitamin D are unlikely to increase the risk of cardiovascular diseases.