**1. Chemistry of Vitamin C:**
– Vitamin C is also known as ascorbic acid.
– It exists in reduced form as ascorbic acid and oxidized form as dehydroascorbic acid.
– Ascorbic acid is a weak sugar acid structurally related to glucose.
– Various analytical methods exist for detecting ascorbic acid.
– In biological systems, it is found at low pH and predominantly in the ionized form above pH 5.
**2. Deficiency and Diagnostic Testing:**
– Adequate levels of vitamin C are near 50 μmol/L, and deficiency is below 11.4 μmol/L.
– Plasma vitamin C test is widely used to assess vitamin C status.
– Globally, deficiency is common in low and middle-income countries.
– In high-income countries, prevalence is higher in males than in females.
– Plasma levels saturate at about 65 μmol/L with intakes of 100 to 200mg/day.
**3. Vitamin C Intake and Recommendations:**
– Recommended Dietary Allowance for adults is 90mg/day for men and 75mg/day for women.
– Tolerable upper intake level for adults is 2,000mg/day.
– Smokers require 35mg more vitamin C per day than nonsmokers.
– Inverse relationship between vitamin C intake and lung cancer observed.
**4. Synthesis and Evolution of Vitamin C:**
– Most animals and plants synthesize vitamin C, except for certain species like humans.
– Loss of ability to synthesize vitamin C in various species due to genetic mutations.
– Plants synthesize ascorbic acid through pathways starting with simple sugars like glucose, fructose, or mannose.
– Humans lack the functional GULO enzyme for vitamin C synthesis.
– Loss of synthesis observed in guinea pigs, teleost fishes, bats, and some birds.
**5. Medical Uses and Conditions Related to Vitamin C:**
– Vitamin C is essential for treating scurvy caused by its deficiency.
– Role of vitamin C in preventing or treating other diseases is debated.
– Vitamin C supplementation has not shown an effect on overall mortality.
– Intravenous administration of vitamin C may be necessary to maintain normal plasma concentrations in sepsis.
– Vitamin C intake has been studied for its effects on preventing, reducing duration, and severity of the common cold.
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription dietary supplement. As a therapy, it is used to prevent and treat scurvy, a disease caused by vitamin C deficiency.
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| Pronunciation | /əˈskɔːrbɪk/, /əˈskɔːrbeɪt, -bɪt/ |
| Trade names | Ascor, Cecon, Cevalin, others |
| Other names | l-ascorbic acid, ascorbic acid, ascorbate |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a682583 |
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| Routes of administration | By mouth, intramuscular (IM), intravenous (IV), subcutaneous |
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| Pharmacokinetic data | |
| Bioavailability | Rapid, diminishes as dose increases |
| Protein binding | Negligible |
| Elimination half-life | Varies according to plasma concentration |
| Excretion | Kidney |
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| E number | E300 (antioxidants, ...) |
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| ECHA InfoCard | 100.000.061 |
| Chemical and physical data | |
| Formula | C6H8O6 |
| Molar mass | 176.124 g·mol−1 |
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| Density | 1.694 g/cm3 |
| Melting point | 190 to 192 °C (374 to 378 °F) |
| Boiling point | 552.7 °C (1,026.9 °F) |
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Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, 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. Vitamin C may be taken by mouth or by intramuscular, subcutaneous or intravenous injection. Various health claims exist on the basis that moderate vitamin C deficiency increases disease risk, such as for the common cold, cancer or COVID-19. There are also claims of benefits from vitamin C supplementation in excess of the recommended dietary intake for people who are not considered vitamin C deficient. Vitamin C is generally well-tolerated. Large doses may cause gastrointestinal discomfort, headache, trouble sleeping, and flushing of the skin. The United States Institute of Medicine recommends against consuming large amounts.
Most animals are able to synthesize their own vitamin C. However, apes (including humans) and monkeys (but not all primates), most bats, most fish, some rodents, and certain other animals must acquire it from dietary sources because a gene for a synthesis enzyme has mutations that render it dysfunctional.
Vitamin C was discovered in 1912, isolated in 1928, and in 1933, was the first vitamin to be chemically produced. Partly for its discovery, Albert Szent-Györgyi was awarded the 1937 Nobel Prize in Physiology or Medicine.