Since COVID-19 hit back in March, Vitamin C has been flying off the shelves and production has been having a hard time keeping up with demand. People are tuned-in to the immune supporting aspects of Vitamin C. Although in high demand now, Vitamin C has been a key nutrient since it was first isolated in 1923, and has been recognized for its important roles in many metabolic functions in the body.
Vitamin C is a water soluble vitamin that is essential to life. It doesn’t accumulate in our fat to toxic levels like fat soluble vitamins can. Unlike most mammals, us humans have lost the ability to synthesize vitamin C and we depend on external sources of vitamin C from our diet and supplements. Citrus fruits, red and green peppers, strawberries, tomatoes, broccoli, brussel sprouts, turnips, and cantaloupe, amongst other fruits and vegetables are all high in the vitamin C department. When we don’t get enough vitamin C we can become insufficient and eventually become vitamin C deficient. This is a disease called scurvy. It is not super common in developed countries, but can happen. An increased need for vitamin C and/or decreased intake or absorption can lead to vitamin C deficient states. It can manifest as fatigue, easy bleeding and bruising, poor wound healing, hair and tooth loss, and joint pain and swelling due to weakening of blood vessels, connective tissue and bone - all of which need Vitamin C. Vitamin C deficiency also contributes to decreased immune responsiveness and increased susceptibility to infection.
Vitamin C is a powerful antioxidant. It is an electron donor and can directly donate electrons and neutralize harmful free radicals. Free radicals are generated from normal metabolism such as active immune cells, as well as through exposure to toxins. Free radicals are molecules that are missing an electron and can damage structures they come in contact with like proteins, lipids, DNA, and cell membranes in our bodies, in order to gain another electron. Neutralizing these free radicals is protective and prevents damage that can lead to inflammation, aging and disease. Vitamin C also acts as a cofactor for many different enzymatic reactions. These reactions can’t go forward without vitamin C present.
Vitamin C is a cofactor for collagen, the basic building block of connective tissues like the skin, teeth, bones, blood vessels, and tendons. It is an important nutrient in wound healing. It is involved in making norepinephrine, one of the main neurotransmitters in the sympathetic nervous system. During stressful times we make more of this neurotransmitter, and use up more vitamin C. Vitamin C also has many positive effects in cardiovascular disease, cancer, allergies, cataracts, and high blood lead levels.
In terms of immunity, vitamin C upregulates the production of white blood cells, enhances the microbial killing by neutrophils while protecting tissues from collateral damage, and reduces proinflammatory molecules. Regular use of vitamin C has been shown to shorten the duration and severity of the common cold, but has not been shown to reduce the risk of becoming ill. It did however halve the incidence of getting a cold for people undergoing heavy physical stress, like intense athletic or military training. Vitamin C has been shown to shorten intensive care unit (ICU) stays, shorten the duration of mechanical ventilation needed in ill patients, and decrease the death rate in patients with sepsis. Studies are underway looking at Vitamin C as part of treatment for hospitalized patients with COVID-19, but anecdotally high dose intravenous vitamin C has been successfully used in the treatment of moderate to severe COVID-19 patients.
Vitamin C is truly a powerhouse nutrient and is definitely on my short list of go tos for helping to improve immunity. I recommend 1-2 grams daily in divided doses and increasing that dose multiple times throughout the day at the onset of illness. One of the signs that you have overdone it is diarrhea and you would then cut back a bit on the dose. Caution is advised in those with G6PD deficiency, kidney disease and kidney stones.