The sufficiency and balance of nutrients in human body are related to the strength of immune system and some infectious diseases. According to the existing nutritional research results, supplementing nutrition to human body will greatly improve human immunity to diseases and play a role in preventing atypical pneumonia. So what is immunity? Immunity is simply the human body's resistance to various diseases, and the resistance comes from the immune system in the body. The immune system consists of immune organs (such as thymus, bone marrow, spleen and lymphoid tissue) and immune cells (such as macrophages, natural killer cells and lymphocytes). A sound immune system has three major functions, one is defense. Strong immunity, can help the body eliminate foreign bacteria and viruses, avoid diseases, and have the defense ability to protect the body from harm; The second is the stable function. Good immune function can help the body to repair or remove dead tissues and cells that are metabolized, damaged or aged in the human body, and keep the internal environment of metabolism in a stable state all the time; The third is the monitoring function. Strong immunity can help the body kill and eliminate abnormal mutant cells. Only when all the functions of the human body reach a balanced state can health be guaranteed, and the nutritional status of the body is closely related to the strength of immune function. In the process of supplementing nutrition, we should pay attention to ensuring the immune ability of the body through balanced nutrition. Three steps of nutrition and immune balance How do several typical immune-related nutrients construct the human nutrition-immune system? First of all, the combination of "VA+Zn" (vitamin A plus zinc) constitutes the first step of the trilogy of balancing nutrition and immunity, which can help prevent viruses from entering the human body and prevent respiratory tract infection. Medical experiments show that vitamin A is an essential substance to maintain the normal function of epithelial tissue, which can promote the differentiation and repair of epidermal cells such as respiratory tract, ensure the integrity of epidermis, and thus resist the invasion of germs. Vitamin A is called "anti-infective vitamin". The synergistic effect of zinc and vitamin A can improve the absorption and operation of vitamin A. Therefore, the simultaneous effect of vitamin A and zinc can effectively prevent the virus from invading. Vitamin C, the second step of constructing a trilogy of balanced nutrition and immunity, helps to kill viruses that enter the human body. Because it can interfere with the virus invading white blood cells, activate white blood cells all over the body, enhance the phagocytosis of white blood cells to viruses, and kill germs, thus enhancing human immunity and protecting human body from viruses. The content of vitamin C in leukocytes of patients with cold decreased obviously. In addition to trace elements, there is taurine. Taurine is an amino acid, which can promote the growth and reproduction of immune system lymphocytes. In addition, it can clear away heat, relieve pain, and relieve the symptoms caused by the self-regulating defense system initiated by the human body to resist viruses-fever, which is the third step of the trilogy of balancing nutrition and immunity. When the human body is seriously injured, taurine also plays the role of clearing away heat and reducing fever, thus enhancing the body's resistance. That is to say, if people, especially children, can supplement a variety of nutrients that are beneficial to improving human immunity in a balanced way and build an immune protection barrier, they can effectively protect the body from viruses.