Vitamin C megadosage in combination with other therapies, but this does not imply vitamin C megadoses in themselves have therapeutic effect. The World Health Organization recommends a daily intake of 45 mg/day of vitamin C for healthy adults, and 25–30 mg/day in infants. The Vitamin C article provides examples of recommendations from individual countries. None exceed 110 mg/day. Vitamin C is necessary for production of collagen and other biomolecules, and for the prevention of scurvy. Vitamin C is an antioxidant, which has led to its endorsement by some researchers as a complementary therapy for improving quality of life. Since the 1930s, when it
Vitamin deficiency Vitamin deficiency A vitamin deficiency can cause a disease or syndrome known as an avitaminosis or hypovitaminosis. This usually refers to a long-term deficiency of a vitamin. When caused by inadequate nutrition it can be classed as a "primary deficiency", and when due to an underlying disorder such as malabsorption it can be classed as a "secondary deficiency". An underlying disorder may be metabolic as in a defect converting tryptophan to niacin. It can also be the result of lifestyle choices including smoking and alcohol consumption. Examples are vitamin A deficiency, folate deficiency, scurvy, vitamin D deficiency, vitamin E deficiency,