vitamin b2

Vitamin B2, also called riboflavin, is a water-soluble B vitamin that the body needs for normal cell growth, development, and function, and to help convert the food you eat into energy. The NIH Office of Dietary Supplements describes it as an essential part of two coenzymes (FMN and FAD) that the body uses for energy production, cellular growth, and the breakdown of fats, certain drugs, and steroids. Riboflavin occurs naturally in foods including eggs, organ meats and lean meats, milk, some vegetables, and grains and cereals that have been fortified with it in the United States.

Most people in the United States get enough riboflavin from food, so deficiency is very rare, and supplements have a clear benefit mainly when intake is inadequate or a deficiency already exists. For migraine, the evidence is mixed: the NIH says some studies suggest riboflavin supplements might help prevent migraine headaches while others do not, and notes only a few small studies. Some headache-guideline groups (such as the American Academy of Neurology and the Canadian Headache Society) consider it a reasonable option to try under a clinician's guidance because side effects are minimal, though they describe the supporting evidence as low quality. For cancer prevention, the NIH says the data are limited and findings are mixed, and that further research, including clinical trials, is needed. There is no good evidence that riboflavin treats or cures any disease beyond correcting deficiency.

The Recommended Dietary Allowance is 1.3 mg/day for adult men and 1.1 mg/day for adult women, increasing to 1.4 mg/day during pregnancy and 1.6 mg/day while breastfeeding. The NIH notes the body absorbs little riboflavin from a single dose above about 27 mg, and the doses studied for migraine prevention (commonly around 400 mg/day) are far higher than the RDA. Talk to your doctor, pharmacist, or a registered dietitian before starting riboflavin supplements, particularly at high doses or for a specific health condition.

According to the NIH, riboflavin has not been shown to cause harm, and intakes from food at many times the RDA have no observable toxicity. Because no adverse effects have been reported, the Food and Nutrition Board did not set a Tolerable Upper Intake Level; however, the NIH cautions that limited data do not prove high intakes are entirely safe and advises against consuming excessive amounts. As with any supplement, people who are pregnant or breastfeeding and those with health conditions should check with a clinician first.

Riboflavin supplements usually cause very few side effects. Because riboflavin is yellow, amounts the body cannot absorb are passed in the urine, which can turn it a bright yellow color. Headache-guideline groups describe this harmless urine discoloration as the main effect seen even at high doses.

The NIH states that riboflavin is not known to have any clinically relevant interactions with medications. Even so, always tell your doctor, pharmacist, and other providers about any supplements and prescription or over-the-counter medicines you take, so they can advise whether a supplement might interact with your medicines or affect how your body absorbs or uses nutrients.