钙的吸收和转运机制及其影响因素

日粮钙主要在十二指肠和空肠吸收，钙的吸收途径有主动和被动转运，当钙的吸收较低时，十二指肠的主动转运增强，大部分的钙主要通过主动过程吸收。当钙到达大肠时，钙通过主动和被动过程吸收。有许多的因素影响钙的吸收和转运，如维生素D、蛋白质、甲状旁腺素相关蛋白、钙磷比例等。

Advances in Mechanism of Calcium Absorption and Transport

There are two ways of calcium absorption:one is active process and another is passive paracellular process.When intake is low,active transcellular calcium transport in the duodenum is up regulated and a larger proportion of calcium is absorbed by the active process than by the passive paracellular process that prevails in the jejunum and ileum.Calcium that reaches the large intestine undergoes absorption there by both active and passive processes.A lot of factors affect calcium absorption and transport,such as Vitamin D,fat,Parathyroid hormone related peptide,ratio of calcium and phosphorus and so on.