Vitamin C (ascorbic acid) is a water-soluble compound synthesized from glucose by plants and most animals. Human (as well as other primates, guinea pigs, some fish, and several species of bats) is unable to synthesize and store vitamin C for an extended period of time. For this reason, it is necessary to provide this vitamin to the body with food or as supplements. Ascorbic acid is vitamin that is most commonly enrolled in the form of final products.
The minimum daily requirement for the vitamin C is the largest of all the vitamins. Is it adequately:
- in infants and children 2 mg/kg body weight,
- human adult 1 mg/kg body weight.
In a variety of morbidity, in people with hypertension, smoking cigarettes, diabetics, and people who are under stress and in pregnant women and nursing mothers the need for vitamin C is increasing and is 1,5 mg/kg body weight.
Rich sources of vitamin C are fresh fruits and vegetables (especially citrus fruits, currants, strawberries, parsley, spinach, cabbage, tomatoes, and green peppers).
Vitamin C is a fragile product, as a result of cooking there is a 50-70% loss of this compound. The absorption of ascorbic acid takes place in the duodenum and small intestine, non-smokers have absorption at 70-80% of a dose of 180 mg/day. However, the intensity of this process closely depends on the size of the taken dose. The bioavailability of vitamin C is 100% for a single dose of 200 mg, above which is reduced. The organism defends itself against too high concentration of ascorbic acid by excretion of its excess by the kidneys.
Absorption process is hindered by:
- abnormal bowel function,
Reference values of the concentration of vitamin C in human plasma shall be 23-86 μmol/l or 0,4-1,5 mg/dl.
The greatest quantities of vitamin C can be found in organs with a high metabolic activity: in the adrenal glands, brain, liver, pancreas, thymus gland, retina, spleen, stomach and lungs.
Long-term ascorbic acid deficiency leads to reduced resistance to infections, difficulty in healing of wounds and to the development of scurvy (gnilca). Its main symptoms include: damage of the capillaries, spontaneous bleeding, gums inflammation and loosening of the teeth.
Vitamin C in the human body serves full range of functions:
- it is a strong antioxidant,
- plays and important role in collagen synthesis,
- accelerates the healing process of wounds and bones confluence,
- meets an important role in the functioning of the immune system,
- participates in the metabolism of fats, cholesterol and bile acids,
- participates in the production of red blood cells,
- has bacteriostatic properties, and even bactericidal relative to certain pathogenic microorganisms,
- has anti-cancer properties,
- affects blood pressure,
- strengthens the antiviral, antifungal and antibacterial activity of white blood cells.
- Szymańska-Pasternak J., Janicka A., Bober J. Witamina C jako oręż w walce z rakiem. Onkologia w Praktyce Kliniczne tom 7, nr 1, 9–23
- Maćkowiak K., Torliński L. Współczesne poglądy na rolę witaminy C w fizjologii i patologii człowieka. Nowiny Lekarskie. 76, 4, 349-356
- Bury P., Godlewski D., Wojtyś P. 1999. Witamina C a nowotwory złośliwe. Praca przeglądowa. Współczesna Onkologia 3(5): 183–187
- Gawryszewska P.A. Witamina C: metabolizm, znaczenie fizjologiczne i zastosowanie w terapii. lipiec 2009. Praca licencjacka na kierunku Biotechnologia. Uniwersytet Warszawski Wydział Biologii