1, water. Water comes from all kinds of food and drinking water. If people don't take certain vitamins or minerals, they may live with diseases for weeks or years, but if there is no water, they can only live for a few days. Water is beneficial to chemical reactions in the body and also plays the role of transporting substances in the living body. Water plays an important role in maintaining the stability of biological body temperature.

2. protein. Protein is an indispensable substance to sustain life. Human tissues and organs are composed of cells, and the main component of cell structure is protein. Protein plays an important role in the growth of the body, the repair of tissues, the regulation of various enzymes and hormones on biochemical reactions in the body, the composition of antibodies against diseases, the maintenance of osmotic pressure and the transmission of genetic information.

3. Fat. Fat is the main nutrient for storing and supplying energy. Each gram of fat provides twice as much heat as the same weight of carbohydrates or protein. Cell membrane, nerve tissue and hormone composition of human body are inseparable from it. Fat also keeps warm and insulated; Support the protection of internal organs, joints and various tissues; Promote the absorption of fat-soluble vitamins.

4. carbohydrates. Carbohydrate is the main nutrient that provides energy for life activities. It widely exists in rice, flour, potatoes, beans and various miscellaneous grains, and is the most important and economical food for human beings. The daily calories provided by such foods should account for 60% ~ 65% of the total calories.

5, vitamins. Vitamins play an important role in maintaining human growth and physiological functions, and can promote the activity of enzymes or serve as one of coenzymes.

6. minerals. Minerals are the main components of human body, with carbon, hydrogen, oxygen and nitrogen accounting for 96% of the total weight of human body, calcium, phosphorus, potassium, sodium, chlorine, magnesium and sulfur accounting for 3.95%, and other trace elements ***4 1.

7. Dietary fiber. Dietary fiber can be divided into soluble dietary fiber and insoluble dietary fiber. The former includes part of hemicellulose, pectin and gum, while the latter includes cellulose and lignin. Among them, apple collagen, as a kind of natural polymer water-soluble dietary fiber, has the function of strongly absorbing and excluding "radiation (positive charge substance)" of human body, and is an essential nutritional balancer for human body.

Baidu encyclopedia-seven nutrients