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Lack of vitamin C and poor utilization of the nutrient are involved in serious virus infections, including COVID-19

Lack of vitamin C and poor utilization of the nutrient are involved in serious virus infections, including COVID-19Vitamin C has a vital role in our immune defense, and having low blood levels of the nutrient can affect the severity of infections such as COVID-19 and influenza, according to a review article published in Aging and Disease. The scientists behind the study also refer to other studies that have looked at large doses of intravenous vitamin C given to patients with sepsis and life-threatening COVID-19 infections. Vitamin C deficiency is a widespread problem for various reasons and that only adds to the problem.

A COVID-19 infection normally starts with the virus infecting nasal cells. From here, the infection spreads to the lower respiratory system. Most people are able to ward off the infection or at least get away with a mild or moderate case. However, if the immune defense is unable to function optimally, acute respiratory distress syndrome also known as ARDS may develop in the lower respiratory tract in severe cases. A major cause is oxidative stress with hyperinflammation that can lead to circulatory failure and death in worst case.
Because vaccines only have limited effect and coronavirus has a unique ability to mutate, researchers continue to look for better prevention strategies and more effective treatments without side effects for helping critically ill patients. In this review article, the scientists looked closer at vitamin C’s many functions and why it is so important to get enough of the nutrient.

The background for considering vitamin C for prevention and treatment

Vitamin C, also know as ascorbic acid, is found in collagen, which is important for the structure of connective tissue, tendons, skin, and bones. Vitamin C is also important for the immune defense and for wound healing. In addition, it is a powerful antioxidant that protects cells against free radicals and oxidative stress.
Most animals are able synthesize the vitamin C they need. However, humans and some animal species have lost this ability to evolution and depend on vitamin C from the diet. Some of the good vitamin C sources are cabbage, red bell pepper, citrus fruit, kiwi, berries, new potatoes, tomatoes, and herbs. Severe vitamin C deficiency may result in scurvy that causes death by internal bleeding Subclinical scurvy, which is very widespread, may cause tiredness, bleeding gums, bruising, poor wound healing and impaired immunity
Previous studies have shown that patients with diabetes, chronic lung disease, hypertension, and life-threatening sepsis have reduced levels of vitamin C in their blood. This has led scientists to conduct studies where they give high doses of intravenous vitamin C to patients with chronic illnesses, sepsis, and COVID-19.

Vitamin C levels and the immune system

Our innate immune defense functions like storm troops and fights most germs silently in the background without us even noticing. Here, vitamin C is important for our ability to produce interferon-α/β in the initial stages of influenza in order to prevent the virus from reproducing in the cells it has attacked. Interferon also stimulates the white blood cells that attack directly. This action requires a lot of vitamin C. White blood cells such as neutrophilic granulocytes and macrophages contain 10-100 times more vitamin C than the amount of vitamin C found in plasma. Vitamin C concentrations in the white blood cells peak when they carry out their so-called respiratory burst, where they attack microscopic enemies using free radicals as missiles. Free radicals are highly reactive molecules and it is vital to make sure that their activity is confined to a limited area so they don’t cause tissue damage and oxidative stress.
Studies suggest that vitamin C helps the immune defense attack swiftly and also serves as an antioxidant that can protect the body’s tissues.

How ageing and other factors block the body’s utilization of vitamin C

Vitamin C is absorbed from the small intestine from where it enters the blood. It is a water-soluble vitamin and is carried through the lipid-containing cell membranes by two vitamin C transporters (SVCT1 and SVCT2), all depending on the type of tissue. Several studies have shown that ageing processes, oxidative stress, inflammation, and certain diseases can down-regulate the vitamin C transporters, causing a vitamin C deficit in the cells.
The scientists assume that changes in the vitamin C transporters may be important factors in ageing and perhaps some population groups are more prone to COVID-19 infection, which is also linked to more serious complications. Furthermore, they say that low vitamin C levels are commonly seen in older people and certain other vulnerable groups such as those with diabetes, hypertension, and other chronic conditions. They call or more studies to map out vitamin C’s therapeutic effect in connection with COVID-19 infections.

Race and gender affect vitamin C levels in the blood

Through the last decade or so, scientists have made studies to see if vitamin C levels in the blood vary according to race and gender. Most studies showed that men generally had lower levels of the nutrient compared with women, even if they ate a diet with a lot of vitamin C. They also found differences in levels of vitamin C between different races and ethnic groups. African-Americans were more likely to lack vitamin C compared with white Americans. The scientists explained that African-American people generally eat less dietary vitamin C and that was not really taken into account in the study. Still, it is a fact that men more often than women get complicated and life-threatening COVID-19 infections and African-Americans also tend to develop more serious cases of the disease than white Americans. Vitamin C may play a key role but it is also important to look at vitamin D, which dark-skinned people have more difficulty with synthesizing. This may also contribute to the difference.

Vitamin C supplements in the case of other virus infections

The scientists mention other studies where vitamin C supplementation has been shown to have a positive effect on virus infections. Daily intake of vitamin C in doses of more than 1,000 mg, which is quite a lot, have been shown to reduce the duration and severity of virus infections. Vitamin C supplements are most effective in the preventative phase. Higher doses should be used at the initial signs of an infection in order to mobilize the innate defense.

Intravenous vitamin C in the case of sepsis

According to WHO, sepsis is the third leading cause of death worldwide. When sepsis becomes life-threatening it is because the immune defense attacks a virus using cytokine storm and hyperinflammation as weapons. This may also result in acute respiratory distress syndrome (ARDS). In many ways, sepsis and COVID-19 are quite similar.
A previous study has shown that if you combine cortisone with vitamin B1 and high quantities of vitamin C, which can be administered intravenously, it can lower the mortality rate from 40 to around 8.5 percent. Another study used large doses of intravenous vitamin C in combination with antioxidants such as selenium, vitamin E, ad NAC (N-acetylcysteine) and demonstrated a 37 percent lower mortality compared with the control group that received standard therapy. Because different doses of intravenous vitamin C have been tested and the results have varied the scientists call for additional studies to show vitamin C’s potential in the treatment of sepsis. Still, the positive outcome of intravenous vitamin C suggests that this type of therapy is well suited in cases with life-threatening COVID-19 infections.

Intravenous vitamin C in the case of life-threatening COVID-19 infections

The review article cites 30 clinical studies where large doses of intravenous vitamin C were given alone or in combination with other types of medicine. Intravenous therapy is much faster and more effective, simply because the body is not able to absorb such high doses from oral supplementation. Also, the treatment is inexpensive and has no side effects. But there is a need for published peer-reviewed studies and data to determine the therapeutic effect of the vitamin.


Vitamin C therapy is known for its ability to strengthen the immune system’s production of interferon and support the activity of white blood cells in their respiratory burst attacks. These mechanisms are very important for the innate immune defense that must be able to work swiftly and precisely. Vitamin C is also able to prevent or neutralize unwanted inflammation and reduce oxidative stress that is the actual reason why COVID19, influenza, and sepsis become life-threatening. Vitamin C therefore has huge potential in the prevention of these diseases.
High-dosed intravenous vitamin C also has a potential for patients with COVID-19. It is inexpensive and without side effects. Our ability to utilize vitamin C is related to diet, ageing processes, gender, and levels of vitamin C transporters.
The authors of the review article want to study if vitamin C therapy can help COVID-19 patients who are older, have diabetes and other underlying diseases, or have certain ethnic backgrounds. It is also relevant to look closer at the relation between levels of vitamin C in serum/plasma, COVID-19 infections, and their severity.

  • When COVID-19, influenza, and sepsis become life-threatening it is because the immune defense overreacts by using cytokine storm and hyperinflammation to attack healthy tissue.
  • It is not the different viruses or bacteria that are life-threatening. It is our own immune defense that goes haywire because it lacks essential nutrients like vitamin C.

How do we get enough vitamin C and what causes deficiency?

Fruit and vegetables are good sources of vitamin C. If you follow the official dietary guidelines you should easily be able to get enough. But most people fail to do so, and ageing, chronic diseases, smoking, stress, poisoning, lesions and overuse of stimulants may increase the need for the vitamin.
The same goes for a large intake of sugar, which is because sugar and vitamin C compete for the same channels into the cells. The more sugar you consume, the more it will reduce the effect of vitamin C.
Particularly vulnerable groups may need to exceed the official recommendations for vitamin C intake.


Taylor Patterson, Carlos M Isales and Sadanand Fulzele. Low level of Vitamin C and dysregulation of Vitamin C transporter might be involved in the severity of COVID-19 infection. Aging and Disease 2021

Claudia Vollbracht and Karin Kraft. Feasibility of Vitamin C in the treatment of Post Viral Fatigue with Focus on Long COVID, Based on a Systematic Review of IV vitamin C on Fatigue. Nutrients 2021

Yejin Kim et al. Vitamin C Is an Essential Factor on the Anti-viral Immune response through the Production of Interferon-α/β at the Initial Stage of Influenza A virus (H3N2) Infection. Immune Netw. 2013

Glenwiew, IL, June 26, 2017. Readily available drug cocktail may help prevent sepsis shock and deaths. Elsevier June 2017

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