More than 50 elements in the human body can be found in nature. There are 1 1 elements in human body, accounting for about 99.95% of human body mass. Elements whose content in human body exceeds 0.0 1% are called constant elements; Elements with a content below 0.0 1% are called trace elements.

Calcium is the most abundant metal element in human body and an important part of human body. Adults contain about 1.2 kg of calcium, 99% of which exists in bones and teeth, mainly in the form of calcium hydroxyphosphate [CA 10 (PO4) 6 (OH) 2] crystals, which makes bones and teeth have hard structural support.

Children and adolescents will suffer from rickets and dysplasia due to calcium deficiency, while the elderly are prone to osteoporosis and fractures. Therefore, the human body must take enough calcium every day. Minors are in the stage of growth and development, and need to consume more calcium than adults.

Milk, dairy products, beans, shrimp skin and other foods are rich in calcium, which is a good source of calcium in daily diet. Patients with osteoporosis and rickets caused by calcium deficiency should take calcium supplements such as calcium tablets under the guidance of doctors.