Vitamin C

Introduction

Vitamin C, also known as ascorbic acid, is an essential nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant.

Biochemistry

Vitamin C is a cofactor in at least eight enzymatic reactions, including several collagen synthesis reactions that, when dysfunctional, cause the most severe symptoms of scurvy. In these reactions, vitamin C is oxidized to form dehydroascorbic acid, which can be reduced back to the active form of vitamin C in the body.

Biological Significance

Vitamin C is an essential nutrient for certain animals including humans. The term "vitamin C" refers to a number of vitamers that have vitamin C activity in animals. Ascorbate salts such as sodium ascorbate and calcium ascorbate are used in some dietary supplements. Ascorbic acid is used in dietary supplements because it is cheaper to produce and has a longer shelf life.

Dietary Sources

Vitamin C is found in high concentrations in many fruits and vegetables, and is also available as a dietary supplement. Vitamin C is also present in some cuts of meat, especially liver. Vitamin C is most present in the skin and least present in the seed of fruit.

Deficiency

A deficiency in vitamin C causes the disease scurvy, which can lead to a number of symptoms, including anemia, bleeding gums, and skin hemorrhages. Severe deficiency can be fatal.

Overdose

Large doses of vitamin C have the potential to cause indigestion, particularly when taken on an empty stomach. However, it is worth noting that while vitamin C is classified as a dietary supplement, excessive amounts of it can still be harmful.

Pharmacology

Vitamin C is a water-soluble vitamin, with dietary excesses not stored in the body, but excreted in the urine. It has a half-life of about 2 weeks. The body's pool of vitamin C can be depleted in under a month if no new vitamin C is consumed.