Why does vitamin C not enhance the body’s immunity against the new coronavirus?

BEIJING, April 9 ( Xinhua) — According tomedia reports, vitamin C is unlikely to help people fight the new coronavirus, which is not risky, but has no effect. When people have the common cold, they drink orange juice, take vitamin C supplements, and try to increase their immunity, but in fact vitamin C does not protect most people from the common cold.

Why does vitamin C not enhance the body's immunity against the new coronavirus?

Vitamin C can only shorten the time spent on cold recovery in the general population

Linus Pauling, a two-time Nobel laureate, touts the health benefits of vitamin C in a series of books, after which it is a special nutrient that boosts immunity. Bowling claims that taking large doses of vitamin C not only prevents the common cold, but also helps prevent more serious diseases, such as cancer and heart disease.

Since Bowling published his book in the 1970s, his bold claims about vitamin C have not been scientifically tested, but according to a 2013 review of dozens of studies, vitamin C supplements can shorten the time it takes for the general population to recover from colds.

Taking vitamin C supplements during a cold can reduce illness by 8% in adults and 14% in children, the review showed. In practice, this means that vitamin C supplementation can shorten the cold time of the day, and each study participant is known to take vitamin C at different times, usually at least 200 milligrams a day.

Several of the studies were conducted on people who were under enormous physical stress, including marathon runners and Arctic-trained soldiers. In these groups, people taking vitamin C are half as likely to catch a cold as the general population, but for the general population, vitamin C does not prevent the common cold.

Similarly, we have no evidence that vitamin C supplements can help prevent new coronaviruses, said Dr. William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in the United States.

“If taking vitamin C has some advantages, it’s very limited, ” Schaffner said. “Currently, some scientists are testing whether taking a dose of vitamin C is large enough to relieve symptoms in patients with the new coronavirus. In February, researchers at Wuhan University’s Zhongnan Hospital conducted a clinical trial of 140 patients to test whether intravenously ultra-high doses of vitamin C were more effective in treating viral infections than placebos. The test takers were tested twice a day for seven days, each with 12 grams of vitamin C fluid (doctors recommend that adults consume only 90 mg of vitamin C per day).

The trial, which will be completed in September, has no concrete results yet, while scientists have launched dozens of other clinical trials to test the effectiveness of everything from antiviral drugs to antibody therapies.

Can be mediumd at the human body free radicals

Although vitamin C supplementation does not prevent the common cold, it is good for human health, and according to a 2017 study in the Journal of Nutrition, vitamins play an important role in the body and support normal immune function.

Vitamin C is an antioxidant that neutralizes free radicals produced by normal metabolism and exposure to environmental stress( including ultraviolet radiation and air pollution), a charged particle that, if unsuppressed, can damage cells, tissues and genetic material, triggering harmful inflammation.

According to a 2017 study, vitamin C, in addition to blocking free radicals, helps activate several key enzymes in the body that continue to synthesize hormones and collagen, a hard protein found in the skin and connective tissue. These hormones help control the cardiovascular system’s response to severe infections, while collagen helps protect the skin from damage.

Through cell culture and clinical studies, the researchers say vitamin C also enhances the fat membranes of the skin and connective tissue, protecting organs such as the lungs from pathogens. A 2017 study found that vitamin C helps immune cells called neutrophils reach the infected site directly and protect them from free radicals when bacteria are determined to invade the body.

In short, the body relies on vitamin C to initiate an effective immune response while maintaining minimal physical damage. However, according to the National Institutes of Health, the body cannot make vitamin C or store the nutrient effectively because the water-soluble vitamin dissolves once it is ingested and excreted with urine. Therefore, the best way to meet your daily vitamin needs is to eat vitamin-rich fruits, vegetables and fortified foods.

The recommended dose of vitamin C depends on the age, sex, pregnancy and lactation status of the person, but in general, it is recommended that adult men consume at least 90 mg per day and adult women at least 75 mg per day, and smokers should increase the recommended dose by 35 mg, as smoking consumes the vitamin C available in the body.

It’s worth noting that high doses of vitamin C (more than 2,000 milligrams a day) can cause nausea, diarrhea and abdominal pain, and that men with high kidney stones and oxalate index should avoid vitamin C supplementation, which boosts kidney stones, said Stephen Lawson, a researcher at Oregon State University’s Linus Bowling Institute.

Beware of hype and making headlines

Although vitamin C supplements pose little risk to consumers, some so-called “immune-boosting” products can be harmful to the body.

Since the outbreak in the U.S., the U.S. Food and Drug Administration (FDA) and the Federal Trade Commission (FTC) have issued warning letters to seven fraudulent sales companies that have pledged to cure and prevent viral infections, and Federal Trade Commission Chairman Joe Simons said in a press release that they are only the first step and are ready to take enforcement action against companies that continue to sell fraudulent products.

‘It’s important to note that there is no evidence that so-called immune-boosting supplements,such as zinc, green tea or echinacea, help prevent new coronavirus infections, and I don’t recommend that people pay for supplements for this purpose,’ said Dr. Mark Mulligan, director of the Center for Infectious Diseases and Vaccines at New York University Langeney Medical Center. (Ye Ding Cheng)