Vitamin C can promote the production of interferon in large quantities in the body, which can enhance immune function and prevent various infectious diseases and cancer，On January 22, 2020, the Pharmaceutical Administration Office of Shanghai Health Commission was the first to explicitly list vitamin C as a COVID-19 prevention drug；

   On 27 January 2020, the Leading Group on the Handling of novel Coronavirus Pneumonia in Shandong Province (hereinafter referred to as the Ministry of Coronavirus) also issued a document calling on everyone to avoid air conditioning as much as possible, strengthen nutritional intake and take vitamin C supplements appropriately，Function of vitamin C：

1、Improve the immunity of human body：

    Vitamin C can enhance the chemotaxis and deformation energy of neutrophils and improve the germicidal ability.It can promote the generation of lymphoblastic cells and improve the recognition and killing of foreign and malignant cells.In addition, vitamin C is involved in the synthesis of immunoglobulin; Promote the generation of interferon, interfere with the transcription of viral messenger ribonucleic acid, inhibit the proliferation of virus, from many aspects to improve the human body's resistance to disease.Accordingly, in cold popular season can complement vitamin C appropriately, prevent and cure respiratory tract infection, prevent a cold；

2、Participates in collagen synthesis：

    Human body is made up of cells connected by the intercellular stroma, a key component of which is collagen.Collagen makes up a third of the body's protein and is involved in building the connective tissue that forms the body's scaffolding；

    Vitamin C plays an important role in the synthesis of collagen.A deficiency of vitamin C, for example, can lead to a breakdown of cell connections, and blood vessels are prone to rupture and flow to nearby tissues；

3、Antioxidation：

     Free radicals produced by oxidative damage of the body can invade various human cells and lead to cancer by invading DNA.Encroaching on blood vessels speeds up hardening of the arteries;Invading the lens of the eye can cause cataracts and so on.Therefore, anti-oxidation is an important measure for health preservation and disease prevention，Vitamin C is A powerful antioxidant that protects other antioxidants such as vitamins A and E from oxidative damage.It can inhibit the generation of lipid peroxidation free radicals, block lipid peroxidation, and prevent the harm of free radicals to human body；

4、Participates in cholesterol metabolism：

    Vitamin C can promote cholesterol hydroxylation and excretion, prevent cholesterol deposition in the inner wall of the artery, play the role of preventing arteriosclerosis；

5、Promotes iron, calcium and folic acid absorption：

   Iron in food is divided into heme iron and non-heme iron.Heme iron is divalent iron with high absorption rate.Non-heme iron is trivalent iron, which needs to be converted into divalent iron in the body before it can be absorbed by the human body. Vitamin C can reduce the trivalent iron to divalent iron and promote iron absorption；

   Calcium in the digestive tract in a soluble state is the basic condition for absorption.Vitamin C can form an acidic medium in the stomach to prevent the formation and precipitation of insoluble calcium complex and promote the absorption and utilization of calcium；

6、Detoxification：

     Vitamin C is reputed to be a universal antidote, promoting the formation of liver glycogen, which plays an important role in liver detoxification; At present, it is a common problem that harmful heavy metals pollute the environment. Vitamin C can directly participate in the detoxification process of heavy metals and effectively prevent the toxic effects of harmful heavy metals such as lead, cadmium and mercury on human body.The inner wall of veins deposits, play a role in preventing arteriosclerosis；

7、Cancer prevention：

     Antioxidant effect of vitamin C can resist the damage of free radicals to cells and prevent cell variation;Blocking nitrite and secondary amine form a strong carcinogen nitrosamine.In addition, vitamin C promotes collagen synthesis, which helps prevent cancer cells from spreading；

    Vitamin C is one of the most widely used vitamins in the human body. It is vital to human health and is commonly known as the nutrient to maintain life -- vitamin C；