Medical Definition of Vitamin B2

Reviewed on 3/29/2021

Vitamin B2: An essential nutrient found in meat, dairy foods, plant foods and grain products. The body requires vitamin B2 to break down food components, maintain tissue, and absorb other nutrients.

Like other vitamins, vitamin B2 is an organic compound. An organic compound is a substance that (1) occurs in living things, or organisms (hence, the word "organic") and (2) contains the elements carbon and oxygen (hence, the word "compound," meaning combination of elements). An alternate name for vitamin B2 is riboflavin.

Vitamin B2 is a water-soluble vitamin, one that cannot be stored by the body except in insignificant amounts. It must be replenished daily.

Purposes and Benefits of Vitamin B2

Vitamin B2 helps break down carbohydrates, fats and protein for use by the body. Its role in maintaining an energy supply for the body is crucial, for it helps convert carbohydrates into adenosine triphosphate (ATP), a compound needed to store energy in muscles. Vitamin B2 also promotes the following:

1. Skin, muscle, nerve, heart and eye health, including inhibiting the development of cataracts.

2. Production of red blood cells and antibodies.

2. Absorption or activation of iron, folic acid and Vitamins B1, B3 and B6.

3. Conversion of tryptophan, an amino acid, into niacin.

4. Production of hormones by the adrenal glands.

5. Maintenance of the mucous membranes in the digestive system with the help of vitamin A.

6. Healthy development of the fetus. (Vitamin B2 may or may not be essential for normal fetal development but it is clearly the better part of wisdom to supply it via the mother's diet.)

Food Sources of Vitamin B2

Vitamin B2 is found mainly in meat, fish, eggs, vegetables, dairy foods and grain products. Types of food containing vitamin B2 include the following:

1. Liver, beef kidneys, chicken, turkey, fish.

2. Eggs, cheese, milk, yogurt.

3. Leafy green vegetables, asparagus, artichokes, avocados, broccoli, Brussels sprouts, dandelion greens, watercress, currants, spinach, kelp, peas, navy beans, lima beans, pumpkins, sweet potatoes, cayenne, parsley, sage, rose hips.

4.Whole-grain breads, enriched breads, fortified cereals.

5. Mushrooms, nuts, molasses.

Deficiency of Vitamin B2

Vitamin B2 deficiency is quite uncommon. Those most vulnerable to deficiency of vitamin B2 include alcoholics, elderly persons with a poor diet, persons who suffer adverse reactions to dairy products (lactose intolerance) and women who use oral contraceptives.

The signs and symptoms of vitamin B2 deficiency include visual problems, such as cataracts and excessive sensitivity of the eyes to light (photosensitivity). There may also include reddening of the lips with cracking at the corners (cheilosis), tongue inflammation (glossitis), skin inflammation (dermatitis), swelling (edema), dizziness, hair loss, insomnia, trembling and delayed mental response.

Preservation of Vitamin B2

Foods lose Vitamin B2 when exposed to light. Therefore, they should not be stored in transparent glass containers.

Recommended Daily Intake of Vitamin B2 in Milligrams

Infants from birth to 1 year: 0.4 to 0.5 mg

Babies 1 to 3 years: 0.8 mg

Children 4 to 10: 1.1 to 1.2 mg

Pregnant women: 1.6 mg

Lactating women: 1.7 to 1.8 mg

Other adult females: 1.3 mg

Adult males: 1.7 mg

(Intakes may be adjusted according to a physician's instructions.)

A milligram equals 1/1000 of a gram. A gram equals .0353 of an ounce.

Side Effects From Overdose of Vitamin B2

Vitamin B2 is not known to cause overdose side effects because excessive amounts are not retained by the body.

Interactions of Vitamin B2

Vitamin B2 may interact with some drugs. Therefore, patients taking drugs should always read warning labels and advisories on containers and printed pharmacy instructions. If in doubt about a possible reaction, patients should consult a pharmacist or physician.

Vitamin B2 Supplements

Vitamin B2 is usually sold as part of B-complex or multivitamin products in the form of tablets, powders and liquids.


The "vita" in "vitamin" is derived from the Latin word "vita" (life). A vitamin, thus, is a nutrient required to sustain life.



According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

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