Nutrition, originally meant to seek health, refers to the role of human beings in absorbing nutrients from the outside world to maintain life activities such as growth and development. Or the process that the human body obtains and uses the materials and energy necessary for its life activities. Therefore, nutrition represents an action, behavior or biological process [1].

It should be noted that "nutrition" is not the same as food or nutrients. The understanding of the word nutrition in society is not correct enough, and the words are not appropriate, such as "rich nutrition", "rich nutrition" and "with or without nutrition". It is correct to change it to "nutritious" or "nutrient-rich". A person's nutritional status refers to the physical condition related to nutrition, that is, the health status of food ingredients and the utilization status of nutritional ingredients. Can be divided into individuals and groups. Generally, some special nutrients are involved, and sometimes there is a comprehensive evaluation of all nutrients, that is, the overall nutritional status, such as iron, protein and vitamins [1].

Nutrition is a science that studies the effects of food on living things. In its development process, nutrition not only includes the changes of food entering the body, such as participating in biochemical reactions and combining with tissues and cells; It also includes instructing people how to choose food to ensure the normal growth, development and reproduction of the body. Therefore, nutrition has not only biological significance, but also social and economic significance.