Calcium is the most abundant inorganic element in human body and has many important physiological functions, mainly involved in the composition of bones and soft tissues. If the human body does not take enough calcium, it may cause rickets and osteoporosis. Children need more calcium in the process of growth and development. If the calcium intake is insufficient, they may suffer from rickets. Women of childbearing age have a great demand for calcium, and menopausal women and elderly women are prone to osteoporosis due to calcium deficiency. Calcium supplement should be based on food supplement. The diet of calcium supplementation is mainly based on eating more milk and soybeans. Among them, milk is not only a source of high-quality protein, but also a food rich in calcium. Every 100 ml of milk contains 120 mg of calcium, and the absorption rate of calcium in milk can reach more than 40%. If you drink 250 ml of milk every day, you can get 300 mg of calcium, which is equivalent to 40% of the human body's demand for calcium, and then take some calcium from other foods, which can basically meet the needs of ordinary people. Especially the high calcium milk added with "active calcium factor" has higher absorption and utilization rate. You can also choose yogurt, cheese and other dairy products. In addition, green leafy vegetables (except spinach), soybeans and bean products, sesame sauce, small fish and shrimps, kelp and laver are all rich in calcium. Especially, shrimp skin contains the highest calcium content, and 100 g shrimp skin contains 2000 mg of calcium. Teenagers should choose these foods to supplement calcium. Vitamin D can promote the absorption of calcium in intestine and increase the level of calcium in plasma. Appropriate supplementation of foods rich in vitamin D while supplementing calcium can get twice the result with half the effort. In addition, sufficient ultraviolet radiation can promote the synthesis of vitamin D in human body and improve the absorption rate of calcium. Therefore, increasing physical exercise, joint exercise and muscle stretching can improve the nutritional status of skeletal muscle and increase bone density. While supplementing calcium, some foods containing too much oxalic acid should not be eaten, such as spinach, bamboo shoots, lettuce and water bamboo. Because there is a lot of oxalic acid, and oxalic acid is easy to combine with calcium to form water-insoluble calcium oxalate, which affects the absorption of calcium and makes your calcium supplement work in vain. Due to the dietary habits and food supply problems in China, it is still difficult for teenagers, women of childbearing age, menopausal women and elderly people who need calcium supplementation to greatly increase their calcium intake through dietary channels. Therefore, calcium should be properly supplemented. When choosing calcium agent, calcium agent with high calcium content, small side effects, no irritation to gastrointestinal tract, reasonable price and long-term use is better. At present, there are many kinds of calcium agents on the market. Traditional calcium agents include calcium carbonate, calcium gluconate, calcium acetate and calcium chloride. Among them, calcium carbonate has the highest calcium content, reaching 40%. In addition, there are calcium agents produced by natural biological raw materials such as bone meal and oyster shell powder, but these raw materials are often polluted by metals, which are harmful to the health after long-term use. Therefore, from the content and price of elemental calcium, calcium carbonate is ideal. Vitamin D is added to other calcium supplement products, which is more conducive to the absorption of calcium (sorry, I can't name the product to prevent advertising). Add one tablet a day, plus calcium in dairy products and other diets, which can basically meet the needs of body growth and development. Of course, it should be noted that the traditional calcium agent can completely meet the needs of human body to supplement calcium, and the price is very low. Some so-called new products only add a little on the basis of traditional products, and their prices have risen several times and ten times. Therefore, when purchasing calcium supplement products, we must polish our eyes and make an analysis. For example, you can add your own elements, and there is no need to spend dozens of times more money to buy this expensive product. Recommended recipe-1, shrimp skin tofu: ingredients: tofu, shrimp skin, refined salt and monosodium glutamate. Production: cut tofu into three parts, blanch with boiling water, remove and drain; Sprinkle with shrimp skin. Dissolve salt and monosodium glutamate in a little boiling water, pour it on the shrimp skin tofu and mix well. 3. Scrambled eggs with shrimp sauce: 2 tablespoons of shrimp sauce, 2 eggs, green pepper 1 piece. Production: break the eggs, chop the peppers, add shrimp paste and egg mixture and mix well. Take the pan and use medium heat. When the oil is hot, put the stirred raw materials into the pan and stir fry until the eggs are cut into pieces. If this dish is accompanied by mixed rice flour of corn flour, millet flour, rice flour and chestnut flour, it is a famous dish-"Shrimp Sauce Wotou". Dissolve salt and monosodium glutamate in a little boiling water, pour it on the shrimp skin tofu and mix well. 3. Scrambled eggs with shrimp sauce: 2 tablespoons of shrimp sauce, 2 eggs, green pepper 1 piece. Production: break the eggs, chop the peppers, add shrimp paste and egg mixture and mix well. Take the pan and use medium heat. When the oil is hot, put the stirred raw materials into the pan and stir fry until the eggs are cut into pieces. If this dish is accompanied by mixed rice flour of corn flour, millet flour, rice flour and chestnut flour, it is a famous dish-"Shrimp Sauce Wotou".