Vitamin B2

What Vitamin B2 does

Riboflavin (vitamin B2) is a water-soluble B vitamin that is an essential component of two major coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which play major roles in energy production; cellular function, growth, and development; and metabolism of fats, drugs, and steroids; FAD is required to convert tryptophan to niacin, FMN is needed to convert vitamin B6 to its coenzyme, and riboflavin helps maintain normal levels of homocysteine. Because riboflavin is required for mitochondrial function, researchers are studying its potential use to prevent or treat migraine headaches; some, but not all, small studies have found a beneficial effect, and the American Academy of Neurology/American Headache Society concluded it is probably effective for preventing migraine headaches, though the Canadian Headache Society notes the supporting evidence is of low quality. Experts have also theorized riboflavin might help prevent DNA damage caused by carcinogens, but data on riboflavin and cancer prevention or treatment are limited and study findings are mixed, and the NIH states future studies including clinical trials are needed to clarify these relationships. Riboflavin is not known to have any clinically relevant interactions with medications. — per the NIH Office of Dietary Supplements; not medical advice.

Forms & absorption

Riboflavin is available in many dietary supplements, including multivitamin/mineral supplements (which commonly provide 1.3 mg, 100% of the Daily Value), riboflavin-only supplements, and B-complex vitamins that include riboflavin. In most supplements riboflavin is in the free form, but some supplements contain riboflavin 5'-phosphate. About 95% of riboflavin as FAD or FMN from food is bioavailable up to a maximum of about 27 mg per meal or dose, and the bioavailability of free riboflavin is similar to that of FAD and FMN.

Food sources of Vitamin B2

Foods that are particularly rich in riboflavin include eggs, organ meats (kidneys and liver), lean meats, and milk; some vegetables also contain riboflavin, and grains and cereals are fortified with riboflavin in the United States and many other countries. The largest dietary contributors of total riboflavin intake in U.S. men and women are milk and milk drinks, bread and bread products, mixed foods whose main ingredient is meat, ready-to-eat cereals, and mixed foods whose main ingredient is grain. (Among selected foods, pan-fried beef liver is especially high, at 2.9 mg per 3-ounce serving.) — per the NIH Office of Dietary Supplements.

Vitamin B2 deficiency — who's at risk