The eight major nutrients are protein, fat, carbohydrates, inorganic salts, vitamins, water, dietary fiber, and probiotics. Nutrients are necessary to maintain human growth and development, provide energy, and generally need to be obtained from the diet. 1. Protein: It is an important part of the cells of the body, constitutes various enzymes necessary for the body and has a catalytic effect; it can provide energy, enhance one’s own resistance, and help wound healing. 2. Fat: is the body’s energy storage and supply of energy; phospholipids, glycolipids and cholesterol constitute the lipid layer of the cell membrane; maintain body temperature and protect the internal organs. 3. Carbohydrates: mainly supply calories, promote growth and development, conserve protein, and regulate fat metabolism. 4. Inorganic salts: mainly can maintain the water electrolyte balance, maintain the osmotic pressure of cells, regulate physiological functions, maintain nerve and muscle excitability. 5. Vitamins: the body to maintain normal physiological functions and must be obtained from the food of a class of trace organic substances, can promote growth and development, involved in the regulation of body metabolism. 6. Water: can maintain the normal cell structure of the body, assist metabolism, transportation of nutrients in the body, to maintain the body’s blood volume, regulate body temperature, moisturize the body tissues, to ensure the stability of the body’s circulatory system and so on. 7. Dietary fiber: can promote gastrointestinal peristalsis, accelerate digestion and absorption of food, laxative, stabilize intestinal flora, reduce the rate of sugar absorption, but also regulate caloric intake, weight control. 8. Probiotics: can regulate gastrointestinal, promote digestion, promote the absorption of nutrients.