长期缺乏钙营养会不知不觉地给老年人带来许多疾病（Chronic lack of calcium nutrition can unwittingly bring many diseases to the elderly）.doc

长期缺乏钙营养会不知不觉地给老年人带来许多疾病（Chronic lack of calcium nutrition can unwittingly bring many diseases to the elderly） The scaffold of the human body is bone, and the main component of the skeleton is calcium, which is the most abundant element in the human body. Calcium accounts for 1.5%-2.0% of the body weight, 99% of which are concentrated in the bones and teeth. The main forms are calcium hydroxide and lime, and 1% are found in the extracellular fluid and the internal fluid, also known as the mixed calcium pool. Miscible calcium pool and maintain a dynamic balance of bone calcium, bone calcium in continuously released into the miscible calcium pool, and miscible calcium pool a few calcium deposition in bone cells, this is bone renewal process. This calcium turnover rate is about 700 mg per day for adults. The rate of calcium turnover slows down with age, and the bones of young children are renewed every one or two years, while adults need ten to twenty years to renew them. Men over 18 years of age, women are more early, the length of the bone began to stabilize, but the bone density continues to increase in the number of years after the age of 40, inorganic substances in bone decreased, the decrease rate is generally greater than the male female It differs from man to man. but, physical activity can slow the process. The biological function of calcium can be divided into two types, one in the formation of bone and soft tissue structure and function in the process of; second cell secretion, signal transmission, chemical and electrical stimulation of the neuromuscular transmission, blood coagulation and blood oxygen transport in the process of adjusting function. In addition to obtaining external calcium from the diet, the daily gut itself can secrete 200-500 mg of calcium, total calcium in the intestine so there is 1.2-1.5 grams, but only 45% of them can be absorbed or reabsorbed into the blood, the residual calcium excreted. Plasma calcium is an important part of its lev