Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin. Unlike most mammals and other animals, humans cannot synthesize vitamin C and obtain it from the diet.
Functions of Vitamin C
Vitamin C (L-ascorbic acid) is a potent reducing agent, easily donating electrons to recipient molecules. In relation to this oxidation-reduction potential, two main functions of vitamin C are as an antioxidant and as an enzyme cofactor (this balance is crucial for the proper functioning of our body’s oxidation-reduction system, which we talked about earlier on the topic of peroxidation).
Vitamin C is the main non-enzymatic, water-soluble antioxidant in plasma and tissues. Even in small amounts, vitamin C can protect molecules critical to the body, such as proteins, lipids (fats), carbohydrates, and nucleic acids (DNA and RNA), from damage caused by free radicals and reactive oxygen species generated during normal metabolism, by active immune cells, and by exposure to toxins and pollutants (e.g., certain chemotherapy drugs and cigarette smoke).
Vitamin C is also involved in recycling the redox reaction of other important antioxidants; for example, vitamin C regenerates vitamin E from its oxidized form.
Symptoms of vitamin C deficiency, such as poor wound healing and lethargy, are likely due to the deterioration of these vitamin C-dependent enzymatic reactions leading to synthesis.
Vitamin C’s ability to influence DNA methylation status and histones in mammalian cells supports the vitamin’s role in health and disease beyond what was previously understood, particularly by safeguarding the integrity of the genome.
Role in Immunity
Vitamin C affects several components of the human immune system in vitro. For example, it has been shown to stimulate the production and function of leukocytes (white blood cells), especially neutrophils, lymphocytes, and phagocytes.
Vitamin C, through its antioxidant functions, has been shown to protect leukocytes from self-inflicted oxidative damage. Phagocytic leukocytes also produce and release cytokines, including interferons with antiviral activity.
Finally, vitamin C is also known to increase the bioavailability and absorption of non-heme iron in the gut.
Therapeutics of vitamin C in various conditions
Breast cancer
Two large prospective studies found that dietary intake of vitamin C is inversely associated with breast cancer incidence in certain subgroups. In the Nurses’ Health Study, premenopausal women with a family history of breast cancer who consumed an average of 205 mg/day of vitamin C from food had a 63% lower risk of breast cancer than those who consumed an average of 70 mg/day.
Stomach cancer
Several observational studies have found that increased dietary vitamin C intake is associated with a lower risk of gastric (stomach) cancer, and laboratory experiments indicate that vitamin C inhibits the formation of carcinogenic N-nitrous compounds in the stomach. In an observational study that included 1,387 men, high intakes of vitamin C were associated with lower serum uric acid concentrations.
Diabetes mellitus
A 12-month randomized, placebo-controlled trial in 456 participants with type 2 diabetes treated with metformin examined the effect of vitamin C (500 mg/day) or aspirin (aspirin; 100 mg/day) on risk factors for diabetes-related complications such as cardiovascular events. Both vitamin C and aspirin reduced fasting blood glucose and glycated hemoglobin concentrations and improved the blood lipid profile in patients treated with metformin. Compared to placebo.
Intravenous Vitamin C
Some of the potential benefits of intravenous vitamin C include:
- Increased absorption: Vitamin C is more efficiently absorbed when administered directly into the bloodstream through an intravenous line than when taken orally. This can benefit those who have difficulty properly absorbing vitamin C through the gastrointestinal tract.
- Antioxidant properties: Vitamin C is a potent antioxidant that can help neutralize free radicals in the body, which can contribute to the prevention of chronic disease and premature aging.
- Support in recovery from illnesses: Some studies suggest that intravenous vitamin C may aid in recovery from certain illnesses, such as colds, flu, viral and bacterial infections, as well as surgeries and injuries (this is due to its stimulating role in the coagulation cascade and production of white blood cells).
- Improved skin health: Vitamin C is essential for collagen production, which can help maintain skin health, reduce inflammation, and promote wound healing.
Contraindications
- Kidney failure: People with kidney failure may have difficulty removing excess vitamin C from the body, which can result in elevated levels of vitamin C in the blood and cause adverse side effects.
- History of kidney stones: People with a history of kidney stones may be more likely to develop calcium oxalate stones if they receive high doses of vitamin C, as it is metabolized into oxalate in the body.
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency: People with G6PD deficiency may experience hemolysis (destruction of red blood cells) if they receive high doses of intravenous vitamin C.
- Interactions with certain medications: Vitamin C may interact with certain medications, such as blood thinners (e.g., warfarin), chemotherapy, and some blood pressure medications, which can increase the risk of side effects.
- Gastrointestinal diseases (relative): People with gastrointestinal diseases such as stomach ulcers, inflammatory bowel disease, or diverticulitis may be more sensitive to intravenous vitamin C administration.
We must remember that both the dose and the route of administration make vitamin C a food supplement and a therapeutic agent under certain circumstances, so it is essential to have a professional assessment before any treatment and to do it according to your needs and clinical conditions.
