With economic development, our standard of living has gradually improved, the average life expectancy has increased, and people’s demand for quality of life has become higher and higher. Osteoporosis is the most common bone disease among middle-aged and elderly people, especially women, and is one of the most important causes of fractures. As China enters an aging society, the impact of osteoporosis on public health is becoming increasingly serious. Calcium is an important nutrient for osteoporosis patients, and is also an essential element for the bone formation phase of the bone reconstruction process throughout the life span. Calcium plays an important role in maintaining healthy bones, therefore, the prevention and treatment of osteoporosis should be preceded by calcium supplementation. People know that calcium supplementation is important, but they are confused about how to supplement and how much to supplement. As an endocrinologist, many people consult me about calcium supplement selection. In order to give you some common sense about calcium supplementation, I have written this article, and I will introduce you to calcium supplementation from the following aspects. The place of calcium in osteoporosis prevention and treatment Calcium and vitamin D supplementation is the basis for the treatment of osteoporosis. Ninety-nine percent of the body’s calcium is stored in the bones, and as the body’s bones develop, the amount of calcium needed increases. The human body reaches its peak bone mass around the age of 35, after which bone mass gradually decreases with increasing age. Calcium is lost in large amounts in patients with osteoporosis, so it is especially important to supplement calcium to maintain bone health. Methods of evaluating calcium nutritional status We all know the importance of calcium supplementation, but little is known about the methods of calcium evaluation. There are three methods of evaluating calcium deficiency. One is serum calcium, but because blood calcium in the body is regulated by many factors and is very stable, studies have shown that there is no obvious correlation between blood calcium and calcium intake, so the clinical use of blood calcium to determine whether the body is deficient in calcium is not comprehensive enough. Secondly, urinary calcium is not a good way to evaluate the adequacy of calcium either, because urinary calcium is not only related to dietary calcium intake, and closely related to dietary sodium and protein, but also influenced by urine volume and calcium requirement. Studies have found that increased protein intake leads to increased urinary calcium. Urinary calcium correlates better with calcium intake in adults, but it decreases in children because the ingested calcium is stored in large amounts in the bones. Third, bone mineral content is measured. This method is relatively accurate and is non-invasive and can be accurately evaluated with dual energy x-rays. What are the manifestations of calcium deficiency? 1. Hypocalcemia: The common cause is a disorder of calcium metabolism rather than insufficient calcium intake. Early manifestations are irritability and high neuromuscular excitability, and later typical hand and foot tics, such as muscle spasms, generalized muscle pain, and “obstetrician’s hand”. 2, osteoporosis: usually occurs in the elderly, especially postmenopausal women, mainly manifesting skeletal deformation, local pain and fractures, but also with osteochondrosis. Older people will become shorter or hunchbacked because of compression fracture. 3. Calcium deficiency rickets: True rickets, caused by insufficient dietary calcium intake, while vitamin D levels can be normal, can only be corrected by calcium supplementation. How much calcium should be supplemented? The calcium requirement of bones depends on the rate of bone calcium renewal. During pregnancy, infancy, childhood and adolescence, the rate of bone calcium renewal is faster and requires large amounts of calcium supplementation. Postmenopausal women also need calcium supplements because they lose bone calcium at a faster rate due to declining estrogen levels. According to different physiological stages, dietary calcium reference intakes have been formulated in order to maintain bone formation, bone resorption and to maintain blood calcium concentration. In 2000, China set the appropriate calcium intake (AI) at 800mg/day for adults aged 18~50 years, 300mg/day and 400mg/day for infants aged 6 months or less and 6 months to 1 year respectively. 600 and 800mg/day for 1~3 and 4~10 years respectively. The AI of calcium for adolescents (11 to 18 years old) is set at 1000mg/day. The AI of calcium for mid- and late pregnancy and lactation is 1000, 1200 and 1200 mg/day, respectively. The maximum intake of calcium for adults is 2000mg/day. How to choose calcium supplements? There are many calcium supplements on the market today, such as Gai Zhong Gai, high calcium tablets, Calcium D, calcium citrate, calcium gluconate, oral calcium solution, etc. There are so many different kinds of calcium supplements that people are at a loss. To summarize, there are about two types of calcium, synthetic calcium and natural calcium. Synthetic calcium includes calcium carbonate, calcium citrate or citrate, calcium acetate, calcium lactate, calcium phosphate, calcium gluconate, calcium oxide, calcium hydroxide, calcium amino acids and other organic acids such as calcium L-threonate; natural calcium is made from the bone powder of various animals or calcined from animal shells. Calcium cannot exist alone outside the body; it must be combined with acid to form calcium salts, which are decomposed into acid roots and calcium ions after entering the body, and calcium ions are the only way for the body to absorb. It is best to choose calcium supplements with high calcium content. calcium content refers to the absolute amount of calcium contained, for example, 1g of calcium gluconate refers to the weight of gluconic acid combined with calcium to form calcium salts, while the element calcium only accounts for 9%, so 1g of calcium gluconate is only 90mg of calcium supplement. most calcium supplements are labeled with the amount of calcium content, for example, 1500mg of Calcium D, which contains 600mg of calcium. safety of calcium supplementation Since osteoporosis is a complex, multifactorial pathological process involved in regulation. Therefore, the treatment should first distinguish which type of osteoporosis the patient is, and treat the cause with relevant drugs and calcium supplements, rather than treating it with calcium supplements alone, such as primary hyperparathyroidism caused by osteoporosis, without treating hyperparathyroidism, calcium supplementation alone is not beneficial but harmful. The dangers of excessive calcium intake 1, ectopic calcification of soft tissues and kidneys, progressive decompensation of kidney function; 2, increased risk of kidney stones; 3, interference with the absorption and utilization of minerals such as iron, zinc and magnesium; 4, the occurrence of lacto-alkaline syndrome, i.e., syndrome of high blood calcium and with or without metabolic alkalosis and renal insufficiency. However, the recommended intake of calcium is almost non-toxic and does not cause an increased incidence of kidney stones and occasional constipation.