Vitamin B2 (Riboflavin)

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By the Nutriveda editorial team · Updated 5 November 2026

Vitamin B2 (riboflavin) is a water-soluble B vitamin that the body builds into two coenzymes, FAD and FMN, which help release energy from food and keep skin, eyes, red blood cells and nerves working normally. EFSA sets a population reference intake of 1.6 mg a day for adults, 1.9 mg in pregnancy and 2.0 mg while breastfeeding. Milk, yogurt, cheese, eggs, almonds, mushrooms and liver are the richest everyday sources. Riboflavin is destroyed by light and leaks into cooking water, which shapes how you store and cook these foods.

What vitamin B2 does

FAD and FMN take part in energy metabolism and in the handling of other nutrients: FMN is needed to turn vitamin B6 into its active form, and FAD is needed to make niacin from the amino acid tryptophan (NIH). That is why a severe shortage of riboflavin can impair the metabolism of other B vitamins. The EU allows these health claims for foods that are at least a source of riboflavin (Regulation (EU) 432/2012):

• “Riboflavin contributes to normal energy-yielding metabolism”
• “Riboflavin contributes to normal functioning of the nervous system”
• “Riboflavin contributes to the maintenance of normal mucous membranes”
• “Riboflavin contributes to the maintenance of normal red blood cells”
• “Riboflavin contributes to the maintenance of normal skin”
• “Riboflavin contributes to the maintenance of normal vision”
• “Riboflavin contributes to the normal metabolism of iron”
• “Riboflavin contributes to the protection of cells from oxidative stress”
• “Riboflavin contributes to the reduction of tiredness and fatigue”

How much you need a day

Group	EFSA population reference intake	For reference: NIH RDA (US)
Men, 18+	1.6 mg	1.3 mg
Women, 18+	1.6 mg	1.1 mg
Pregnancy	1.9 mg	1.4 mg
Breastfeeding	2.0 mg	1.6 mg
Children 1-17 years	0.6-1.6 mg, by age	–
Upper limit (UL)	Not set: no adequate data to derive one	Not set

EFSA derived the adult value from intervention studies that looked at the intake at which riboflavin starts to spill into the urine, with allowances for physical activity and for people with the MTHFR 677TT gene variant. Your body absorbs little from a single dose above about 27 mg; the excess is either not absorbed or leaves in the urine (NIH).

Best food sources

Food	Riboflavin, 100 g	Portion	Per portion
Beef liver, pan-fried	3.42 mg	85 g	2.91 mg
Almonds	1.14 mg	1 oz, 28 g	0.32 mg
Feta cheese	0.844 mg	1 oz, 28 g	0.24 mg
Egg, whole, raw	0.457 mg	1 large, 50 g	0.23 mg
White mushrooms, raw	0.402 mg	1 cup pieces, 70 g	0.28 mg
Pork tenderloin, lean, roasted	0.387 mg	85 g	0.33 mg
Kale, raw	0.347 mg	1 cup, 21 g	0.07 mg
Atlantic mackerel, raw	0.312 mg	85 g	0.27 mg
Whole milk, 3.25%	0.169 mg	1 cup, 244 g	0.41 mg
Plain yogurt, whole milk	0.142 mg	1 cup, 245 g	0.35 mg

Source: USDA FoodData Central, SR Legacy, checked 5 November 2026: beef liver FDC 168627, almonds FDC 170567, feta FDC 173420, egg FDC 171287, mushrooms FDC 169251, pork tenderloin FDC 168250, kale FDC 168421, mackerel FDC 175119, whole milk FDC 171265, yogurt FDC 171284. Portions are USDA household measures; values per portion are calculated and rounded.

Milk and yogurt look modest per 100 g, but because portions are large they are among the biggest contributors: a glass of milk and a cup of yogurt give about half of the 1.6 mg reference. Add two eggs, a handful of almonds and some mushrooms or feta, and most of the day is covered. Without dairy, lean on almonds, mushrooms, eggs, mackerel, sunflower seeds (0.355 mg per 100 g, USDA FDC 170562) and fortified foods.

Light and cooking. Ultraviolet and visible light quickly break riboflavin down, which is why milk is rarely sold in clear glass (NIH); keep these foods out of direct sunlight (NHS). Boiling loses about twice as much riboflavin into the cooking water as steaming or microwaving (NIH).

Deficiency: signs and who is at risk

Deficiency shows as cracks and sores at the corners of the mouth, swollen and cracked lips, skin problems, sore throat and hair loss. These early changes reverse easily with riboflavin, but later changes, such as cataracts, rarely do (NIH). People who lack riboflavin usually lack other nutrients too.

Groups at higher risk (NIH):

• Vegans and people who drink little milk.
• Vegetarian athletes.
• Pregnant and breastfeeding women who rarely eat meat or dairy.
• People with riboflavin transporter deficiency, a rare inherited neurological disorder.

Supplements: when they make sense

Most supplements contain free riboflavin; some use riboflavin 5′-phosphate (NIH). For most people who eat dairy, eggs or almonds, a supplement adds little.

Migraine. In one randomised trial of 55 adults, 400 mg a day reduced migraine attacks by two a month. Two small trials in children with 50-200 mg a day found no benefit. The American Academy of Neurology and the American Headache Society concluded that riboflavin is “probably effective” for preventing migraine (NIH). This is a medical use at doses far above food levels; discuss it with your doctor rather than starting on your own.

Food first remains the rule. A supplement may make sense for vegans who eat few fortified foods, or when a doctor recommends it.

Who should be careful

• Interactions. Riboflavin is not known to have clinically relevant interactions with medicines (NIH).
• High doses. No upper limit has been set by EFSA or in the US, but the US Food and Nutrition Board urges caution with excessive amounts (NIH). The NHS says 40 mg a day or less from supplements is unlikely to cause harm.
• Urine colour. In migraine use, side effects such as discoloured urine are minimal (Canadian Headache Society guideline, cited by NIH).
• Liver in pregnancy. Liver is the richest source in the table, but the NHS advises pregnant women to avoid it.

FAQ

What is vitamin B2 good for?

Riboflavin helps release energy from food and supports normal skin, vision, mucous membranes, red blood cells and nerve function. It also helps the body activate vitamin B6 and make niacin from tryptophan.

Which foods are high in riboflavin?

Per 100 g in USDA data, beef liver has 3.42 mg, almonds 1.14 mg and feta 0.84 mg. In everyday portions, a glass of milk (0.41 mg), a cup of yogurt (0.35 mg) and an egg (0.23 mg) are among the easiest sources.

How much vitamin B2 do I need a day?

EFSA sets 1.6 mg a day for adults, 1.9 mg in pregnancy and 2.0 mg while breastfeeding. A glass of milk, a cup of yogurt, two eggs and a handful of almonds together give about 1.5 mg in USDA data (our calculation).

Related entries and articles

• Eggs and almonds
• Greek yogurt, kefir and feta cheese
• Mushrooms
• Vitamin B6 and vitamin B3 (niacin)
• Vitamin B1 (thiamine) and iron
• Greek yogurt and pomegranate parfait
• Bulgur pilaf with mushrooms and walnuts

Sources

1. EFSA NDA Panel: Dietary Reference Values for riboflavin. EFSA Journal, pub 4919. efsa.europa.eu
2. EFSA: Summary of Dietary Reference Values, version 4 (September 2017). efsa.europa.eu
3. EFSA: Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF), version 11 (August 2025). efsa.europa.eu
4. Commission Regulation (EU) No 432/2012 – permitted health claims. legislation.gov.uk
5. NIH Office of Dietary Supplements: Riboflavin, Fact Sheet for Health Professionals. ods.od.nih.gov
6. NHS: Vitamin B. nhs.uk
7. USDA FoodData Central, SR Legacy: Beef, variety meats and by-products, liver, cooked, pan-fried (FDC 168627); Pork, fresh, loin, tenderloin, separable lean only, cooked, roasted (FDC 168250); Fish, mackerel, Atlantic, raw (FDC 175119). fdc.nal.usda.gov
8. USDA FoodData Central, SR Legacy: Nuts, almonds (FDC 170567); Seeds, sunflower seed kernels, dried (FDC 170562); Mushrooms, white, raw (FDC 169251); Kale, raw (FDC 168421). fdc.nal.usda.gov
9. USDA FoodData Central, SR Legacy: Milk, whole, 3.25% milkfat (FDC 171265); Yogurt, plain, whole milk (FDC 171284); Cheese, feta (FDC 173420); Egg, whole, raw, fresh (FDC 171287). fdc.nal.usda.gov

This page is for information only and is not medical or dietary advice.