Expert Science | Can Vitamin C Prevent COVID-19 Infection? Top 10 Frequently Asked Questions: Experts Answering Viruses, Vitamins, and Viral Infections

I don't know since when vitamin C has become more effective in preventing colds in many people's eyes, and they think that if they eat enough, they can even treat the common cold, influenza or COVID-19 infection. A variety of vitamin C supplements have emerged in the market. So can taking vitamin C to prevent novel coronavirus infection? What are the functions of vitamin C as a medicine? This article answers some of the questions that citizens are concerned about.

Q1: Is vitamin C an essential substance for the human body?

Vitamin C is an essential substance for maintaining normal physiological functions in the human body, and has the function of preventing and treating ascorbic acid, so it is also called ascorbic acid. The human body cannot synthesize it and usually relies on food intake.

Q2: Which foods have high levels of vitamin C?

Vitamin C is usually only present in plant-based foods, while animal based foods generally do not contain vitamin C. It is widely found in fresh fruits such as prickly pear, fresh jujube, kiwifruit, sour jujube, lemon, citrus, hawthorn, sea buckthorn, and strawberry, as well as in green leafy vegetables such as chili, bitter gourd, tomato, Chinese cabbage, lettuce, celery, green pepper, and cabbage. Vitamin C is highly soluble in water and easily destroyed by heat and oxidation. For example, when vegetables are cooked at high temperatures for 5-10 minutes, the loss rate of vitamin C can reach 70% to 90%.

Q3: What is the daily intake requirement for vitamin C?

The requirement for vitamins to maintain normal physiological functions in the human body is relatively low, usually measured in micrograms or milligrams. In terms of daily dietary supply, vitamin C is measured in milligrams, and the recommended daily supply of nutrients for ordinary adults is 100 milligrams. A normal diet can ensure the supply.

Q4: What are the pharmacological effects of vitamin C?

Participating in the formation of human antibodies and collagen, tissue repair includes certain redox reactions, amino acid metabolism, folate metabolism, and neurotransmitter synthesis, which can reduce capillary permeability, accelerate blood coagulation, and maintain vascular integrity. Stimulate coagulation function, promote iron absorption in the intestine, promote blood lipid decline, increase resistance to infection, participate in detoxification function, and have anti histamine effects and prevent the production of carcinogenic nitrosamines.

Q5: Is vitamin C the miraculous medicine mentioned in the book for preventing colds?

In the 1970s, Nobel laureate and American chemist Linus Pauling published a book called "Vitamin C and the General Cold", which explained that vitamin C is a panacea for all diseases. At present, no research can prove that vitamin C can prevent and treat colds, so there is no basis for vitamin C to prevent novel coronavirus infection.

Q6: Is taking vitamin C more beneficial?

In general, most people can obtain sufficient vitamin C from their daily diet without the need for additional vitamin C supplements. Long term consumption of a large amount of vitamin C may lead to abdominal pain, rash, gout induction, and even cause thrombosis, urinary tract stones, kidney damage, etc. Oral vitamin C is absorbed into the bloodstream by the small intestine through concentration diffusion or active transport mechanisms. The preservation rate in the body is related to the dosage, and the smaller the dosage, the higher the preservation rate in the body, which can be completely eliminated from urine. Taking 100 milligrams can completely retain it in the body, with 76% retained at 180 milligrams and 50% retained at 1500 milligrams. At high doses, unabsorbed vitamin C remains in the intestine, affecting osmotic pressure and pH, and can cause diarrhea. Under normal circumstances, the inventory of vitamin C in the human body is 1500mg, and the amount retained in the body does not change with changes in body weight. It is distributed in the aqueous solution of the body, with the highest concentration in the adrenal gland, pancreas, spleen, saliva, and testes, and is mainly excreted through urine.

Q7: Can vitamin C resist infection?

The indications for vitamin C drug instructions are as follows: prevention and treatment of scurvy, various acute and chronic infectious diseases, and auxiliary treatment of purpura; When patients with Keshan disease experience cardiogenic shock, high-dose treatment with this product can be used; Treatment of chronic iron poisoning; Idiopathic methemoglobinemia; Treating liver damage in patients with cirrhosis, acute hepatitis, and chronic poisoning such as arsenic, mercury, lead, and benzene. Therefore, for clinical treatment, vitamin C is an essential nutrient. During infection, the storage of vitamin C in the body may be depleted, and the demand for vitamin C in the body will increase with the severity of the infection.

Photo caption: A close-up photo of Deputy Director Chen Yan, pharmacist

Q8: Can high-dose vitamin C resist novel coronavirus?

The results of a meta-analysis have shown that short-term intravenous vitamin C treatment does not reduce the risk of disease severity and mortality caused by COVID-19. Some clinical trials have also confirmed that high-dose intravenous administration of vitamin C enhances immunity and suppresses inflammatory stress. Recent evidence suggests that oxidative stress and endothelial dysfunction play a key role in COVID-19 infection and long-term positive pathophysiology. Therefore, the therapeutic effect of vitamin C in the period of anti novel coronavirus infection has always been controversial. In the study of respiratory tract infection and critical patients, the results are contradictory, and more evidence-based evidence is needed to prove whether it can really fight against the virus.

Q9: Can ordinary people use high-dose vitamin C to enhance their resistance?

At present, there is no clinical evidence suggesting that the use of high-dose vitamin C in a well nourished general population can significantly reduce the risk of respiratory infections. Supplementing vitamin C can regulate inflammation and have potential positive effects on the immune response to infection in some studies of special disease populations.

Q10: Are there any noteworthy drug interactions with vitamin C?

Vitamin C belongs to acidic substances. When used in combination with sulfonamide drugs such as compound sulfamethoxazole and its metabolites, sulfonamide crystals can easily form in acidic environments, causing urinary system stones and kidney damage. If the condition requires simultaneous use, medication should be taken every 2 hours. When taken together with folic acid, it is prone to undergo redox reactions, leading to a decrease in its efficacy. Combining with aspirin can increase the excretion of vitamin C, thereby affecting its utilization, but vitamin C does not affect the efficacy of aspirin. When taking these two medications, vitamin C should be taken first, and aspirin should be taken at least 1 hour apart. If both medications are needed, the dosage of vitamin C should be increased. Vitamin C has anticoagulant effects against warfarin and heparin, which can shorten prothrombin time and weaken the effect of anticoagulants. When vitamin C is used in combination with alkaline drugs, an acid-base neutralization reaction occurs, causing both drugs to lose their efficacy.

In summary, a balanced daily diet can meet the daily intake of vitamin C in the body, have a positive impact on the immune system, increase immunity, and reduce infections. However, existing clinical research data does not support the conventional additional oral supplementation of vitamin C in the normal population to improve immunity. It is not harmful to eat more, but rather to eat more.