What is the mechanism of action of vitamin C?
Vitamin C (ascorbic acid) dissociates at physiological pH to form ascorbate, the redox state of the vitamin which is found most abundantly in cells [1]. It is well known that ascorbate acts physiologically as a reductant and enzyme cofactor.
How does vitamin C prevent oxidation?
As an antioxidant, vitamin C provides protection against oxidative stress-induced cellular damage by scavenging of reactive oxygen species, vitamin E-dependent neutralization of lipid hydroperoxyl radicals, and by protecting proteins from alkylation by electrophilic lipid peroxidation products.
How does vitamin C affect enzymes?
Protein synthesis This essential vitamin acts as a cofactor to the mixed-function oxidase enzymes that catalyze these chemical pathways. The reaction centers of these enzymes contain bound metals, which remain in their reduced form by vitamin C, thus allowing them to sustain their enzymatic activity.
What are the side effects of taking vitamin C?
Taking too much vitamin C can cause side effects, including:
- Nausea, vomiting and diarrhea.
- Heartburn.
- Stomach cramps or bloating.
- Fatigue and sleepiness, or sometimes insomnia.
- Headache.
- Skin flushing.
How does vitamin C get oxidized?
The oxidation of vitamin C, ascorbic acid, is brought about by the loss of two hydrogen atoms as the vitamin is converted to dehydroascorbic acid.
What happens to vitamin C when exposed to light?
Vitamin C is a water soluble vitamin that can be synthesized by many animals, but not by humans. Therefore, vitamin C should be consumed every day. It is sensitive to heat and light and it is destroyed over time when exposed to atmospheric oxygen (1-5).
What are the biochemical functions of vitamin C?
Vitamin C plays an important role in a number of metabolic functions including the activation of the B vitamin, folic acid, the conversion of cholesterol to bile acids and the conversion of the amino acid, tryptophan, to the neurotransmitter, serotonin. It is an antioxidant that protects body from free radical damage.
How is ascorbate administered to critically ill patients?
Enteral or parenteral nutrition administered to critically ill patients provides ~100 mg/day ascorbate. However, critically ill patients probably require significantly higher intakes of ascorbate [ 21] due to enhanced metabolic turnover of vitamin C during the severe inflammatory response.
Can ascorbate act as an adjuvant therapy for sepsis and septic shock?
Ascorbate-dependent vasopressor synthesis represents a currently underexplored biochemical mechanism by which ascorbate could act as an adjuvant therapy for severe sepsis and septic shock.
Can ascorbate improve endogenous vasopressors in septic patients with hypovitaminosis C?
It is conceivable that administration of ascorbate to septic patients with hypovitaminosis C could improve endogenous vasopressor synthesis and thus ameliorate the requirement for exogenously administered vasopressors.
What is the normal range of ascorbate?
In healthy fasting humans, circulating levels of ascorbate are typically in the range of 50–70 μmol/l, whereas levels <23 μmol/l are considered marginally deficient (or hypovitaminosis C) and levels <11 μmol/l are considered severely deficient and potentially scorbutic [ 23 ].