Riboflavin

Riboflavin, also known as vitamin B2, is a vitamin found in food and used as a dietary supplement. Food sources include eggs, green vegetables, milk and other dairy product, meat, mushrooms, and almonds. Some countries require its addition to grains. As a supplement it is used to prevent and treat riboflavin deficiency and prevent migraines. It may be given by mouth or injection. Riboflavin, also known as vitamin B2, is a vitamin found in food and used as a dietary supplement. Food sources include eggs, green vegetables, milk and other dairy product, meat, mushrooms, and almonds. Some countries require its addition to grains. As a supplement it is used to prevent and treat riboflavin deficiency and prevent migraines. It may be given by mouth or injection. It is nearly always well tolerated. Normal doses are safe during pregnancy. Riboflavin is in the vitamin B group. It is required by the body for cellular respiration. Riboflavin was discovered in 1920, isolated in 1933, and first made in 1935. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Riboflavin is available as a generic medication and over the counter. In the United States a month of supplements costs less than 25 USD. Corneal ectasia is a progressive thinning of the cornea; the most common form of this condition is keratoconus. Collagen cross-linking by applying riboflavin topically then shining UV light is a method to slow progression of corneal ectasia by strengthening corneal tissue. As of 2017 a system is marketed by Terumo in Europe that is used to remove pathogens from blood; donated blood is treated with riboflavin and then with ultraviolet light. A 2017 review found that riboflavin may be useful to prevent migraines in adults, but found that clinical trials in adolescents and children had produced mixed outcomes. In humans, there is no evidence for riboflavin toxicity produced by excessive intakes, in part because it has lower water solubility than other B vitamins, because absorption becomes less efficient as doses increase, and because what exceeds the absorption is excreted via the kidneys into urine. Even when 400 mg of riboflavin per day was given orally to subjects in one study for three months to investigate the efficacy of riboflavin in the prevention of migraine headache, no short-term side effects were reported. Although toxic doses can be administered by injection, any excess at nutritionally relevant doses is excreted in the urine, imparting a bright yellow color when in large quantities. The limited data available on riboflavin’s adverse effects do not mean, however, that high intakes have no adverse effects, and the Food and Nutrition Board urges people to be cautious about consuming excessive amounts of riboflavin. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) function as cofactors for a variety of flavoprotein enzyme reactions: For the molecular mechanism of action see main articles Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)