(1) According to the survey, the incidence of calcium malnutrition caused by vitamin D deficiency in preschool children in China reaches 50%, and the prevalence of pediatric rickets caused by this reaches more than 30%; the incidence of low calcium symptoms in pregnant women reaches 60%, and the prevalence of postpartum osteoporosis reaches more than 10%. The prevalence of osteoporosis in menopausal women is 40%. Some people, for commercial purposes, make a great deal of speculation in the media, promoting “universal calcium deficiency, universal calcium supplementation”, “the more calcium, the better, calcium supplementation can cure all diseases”, so that the abuse of calcium supplements has become a kind of fashionable consumption of the Chinese people. (2) Correctly recognize calcium supplements and do not follow advertisements. Don’t be confused by all kinds of loud names of calcium supplements, and remember that such commercial terms are purely hype, and most of them do not exist in the field of nutrition. Make your choice according to your own needs. (3) Do not listen to exaggerated propaganda. Such as some of the calcium products advertised as “good deposition, fast absorption”, so that people mistakenly believe that the body’s absorption of calcium is a simple process, in fact, calcium into the human body to enter the bloodstream first, and then the formation of calcium-containing cells, and then through complex changes in the process of penetrating the hard layer of the outermost bone, fixed to the inside of the bone. Another advertisement claimed that their products “particles smaller than the average product a number of times”, in fact, the size of the particles is only a physical change, and can not essentially improve the human body on the absorption rate of calcium, the human body on the calcium products in the absorption rate of calcium is only about 30%, in fact, there is no such thing as “95%” absorption rate. In fact, there is no so-called “95%” absorption rate. The first thing to look at when choosing a calcium supplement is what percentage of calcium is in the supplement. Such as: you want to supplement 600mg of calcium, with calcium carbonate as long as 1500mg, calcium citrate will need 2717mg, calcium lactate need 4615mg, calcium gluconate need 6667mg, a variety of amino acids calcium is also more than 5000mg. There are calcium preparations on the market that have a more complex molecular formula than calcium gluconate, and it would take 10 to 15 grams of the preparation to ingest 600mg, which is impossible. Some companies claim that their calcium preparations have a high rate of deposition in the bones, and here there is a question of the body’s threshold for calcium deposition. The general threshold for calcium in the body is 1,000 to 1,500 mg, and any more calcium intake will not raise the calcium threshold and therefore will not deposit more calcium. 4) Special attention should be paid to two calcium preparations. The first is activated calcium, which is made from the shells of offshore oysters, mussels, and shellfish that are activated at high temperatures and then finely ground. This coastal mollusk has a strong adsorption capacity and can adsorb pollutants, lead, mercury and other heavy metals from offshore. Therefore, there are heavy metals in this activated calcium, and the pH is high and alkaline, so there will be gastrointestinal reactions after taking it. The second type of calcium preparation is made from ground up bones of domestic animals, which is also contaminated with heavy metals, especially lead, because heavy metals, especially lead, tend to be deposited in the bones. These two types of calcium preparations, especially active calcium, should be eliminated. (5) Children’s gastrointestinal function is weak, do not choose calcium products with strong alkalinity, such as calcium carbonate, active calcium, etc.; should not drink soda, carbonated drinks, etc. at the same time when taking calcium products, so as not to reduce the absorption rate. Try to improve the dietary structure to achieve the goal of obtaining sufficient calcium from natural foods. In the daily food of the family, those containing more calcium include milk, cheese, eggs, soybean products, kelp, nori, shrimp, sesame, hawthorn, sea fish, vegetables, etc. In particular, milk, per 100g of fresh calcium, should not be consumed at the same time as soda, so as not to reduce the absorption rate. Especially milk, every 100g of fresh milk contains 120mg of calcium, if each person drinks 250g of milk per day, will be able to provide calcium 300mg; drink 500g of milk per day, will be able to supply 600mg of calcium; plus dietary other food supply of about 300mg of calcium, will be able to fully meet the human body on the need for calcium, it is worth noting that, in the consumption of these calcium-rich foods, should be avoided! It is worth noting that when consuming these calcium-rich foods, one should avoid excessive consumption of foods rich in phosphate, oxalic acid, and protein, so as not to affect the absorption of calcium. Nowadays, it is advocated that children should have 4 cups of milk a day, which is less likely to cause calcium deficiency. 6) The more calcium you take, the better it is, the more important it is to look at the absorption. Each time you take more than 200mg of elemental calcium, it will reduce the absorption rate. Overdose of calcium products for children will inhibit the absorption of zinc, so calcium supplementation for zinc-deficient children should be based on dietary supplements. 7) To test the calcium content, you should go to a regular hospital. The “single photon bone density tester” placed in stores and pharmacies can only measure the ulna and radius of the arm, and the main danger of calcium loss is the lack of calcium in the lumbosacral vertebrae and hip bones, so this test is not accurate. And this kind of instrument is a radioactive source, its radiation will have an impact on the body. (8) Calcium products are not the more expensive the better, the current market circulation of calcium products, its quality is not very different. Moreover, different calcium products are suitable for different groups of people. Calcium carbonate contains high net calcium content and high absorption rate, which is the traditional calcium supplement preparation, but it is not suitable for people with stomach acid deficiency; calcium phosphate contains high phosphorus, but it is not suitable for people with chronic renal insufficiency. (9) In the minds of many parents and friends, there exists a kind of wrong understanding, thinking that the child’s excessive sweating, night terrors, poor sleep and other manifestations are “calcium deficiency”, and should be immediately supplemented with calcium. In fact, those symptoms are not necessarily a lack of “calcium”, may also be a lack of vitamin D. Except for newborns will be due to a real lack of calcium can cause convulsions, the rest of the first lack of vitamin D, which leads to calcium and phosphorus metabolism disorders. Therefore, children should pay attention to the supplementation of vitamin D. Supplementation methods include sun exposure and the correct application of vitamin D preparations. According to the scientific research report investigation, the prevalence of rickets in preschool children who take simple calcium preparation every day is basically the same as that of the group who did not take calcium preparation. (10) However, it should be reminded that when taking calcium products with added vitamin D, it is important to prevent accumulation of toxicity. Due to individual differences in children, not all children at the same time both calcium and vitamin D deficiency, some people take vitamin D for a long time instead of inhibiting the formation of their own vitamin D in the body, or triggering a large amount of vitamin D intake and the phenomenon of accumulation of toxicity, toxicity symptoms of hypercalcemia caused by liver and kidney function damage and soft tissue calcification, manifested as loss of appetite, unresponsiveness, arrhythmia, respiratory distress, nausea and vomiting, thirst and polyuria, constipation, etc. (11) Some patients with diseases should take calcium supplements under the guidance of a doctor. Studies have found that improper calcium supplementation in patients with heart disease can cause personal accidents due to calcium deposition. In addition, patients who are taking hormonal drugs such as thyroid hormones and corticosteroids should consult their doctors first when taking calcium supplements, because calcium and such drugs may interact with each other and cause adverse effects on the human body. (12) Incidentally, calcium deficiency in the elderly is an important cause of osteoporosis, and calcium intake should also be enhanced by both improving dietary structure and taking calcium products. It is important to note that calcium supplementation alone cannot prevent osteoporosis in a comprehensive manner. Factors such as endocrine disorders, decreased vitamin D activity, reduced physical activity, excessive salt intake, etc. may all contribute to the development of osteoporosis in the elderly.