At present, more than 40 known nutrients can be roughly divided into six categories, namely: protein, fat, carbohydrates, vitamins, inorganic salts and water. The main functions of nutrients are: (1) main heat energy, which provides heat for human body, such as carbohydrate, protein, fat, etc. (2) It is helpful for human growth and development, and can construct various parts of the body, such as water, inorganic salts, fat, protein, carbohydrates and vitamins. (3) It can regulate essential physiological mechanisms of human body, such as water, vitamins, inorganic salts, fat, protein, etc.
protein
From single cells to complex human organs, protein is the basic substance, and protein is the foundation of life. Protein mainly exists in human muscle tissue, and the rest exists in blood, skin, soft tissue, hair, bones and teeth, accounting for about one third of these tissues. The heat supply in protein accounts for 10% of the total energy required by human body. Therefore, adults need to consume 70-80 grams of protein every day, while developing teenagers need to consume 80-90 grams. Protein is rich in animal foods, such as meat, eggs, fish and plant foods, such as beans.
fat
Fat is an important part of human body, which is divided into lipid and neutral fat. Lipids include phospholipids and cholesterol, and neutral fats, also known as triglycerides, are widely distributed around the skin, abdominal cavity, organs and muscle space. Fat accounts for about 13% of human body weight, and women are higher than men.
The heat production of fat accounts for 16%-20% of the total energy required by human body, and the daily requirement of adults is 50-70g. Eating too much will increase the burden on the digestive system and make it easy to suffer from obesity and cardiovascular diseases. The sources of fat mostly come from milk, egg yolk and plant seeds, such as peanuts, soybeans, sesame seeds, walnuts and other foods.
carbohydrate
Carbohydrate, also known as sugar, is a component of the human body. It is the main source of human energy and plays an obvious role in maintaining health. Adults have about 65,438+0,000 grams of carbohydrates. Carbohydrate is the most effective and economical energy source for human body. Heat can be generated half an hour after a meal, which is the main energy source of the human body. The average adult needs 480-600 grams of carbohydrates every day. Cereals, potatoes, beans, sugars, fruits and vegetables in food are the main sources of carbohydrates.
vitamin
Vitamins are essential for maintaining life and low-molecular-weight organic compounds necessary for maintaining human life and health. Some vitamins are some enzymes and important components in the body, and enzymes are catalysts for biochemical reactions. Therefore, without vitamins, there would be no human life activities.
Vitamins not only participate in the most basic metabolic activities of the human body, but also enhance the anti-inflammatory, disinfection and detoxification functions of the body, which can improve the body's ability to resist diseases.