Vitamin B2, also called riboflavin, is a water-soluble vitamin. Water-soluble vitamins are stored in the body in very limited amounts and are excreted through the urine. Therefore, it is a good idea to have them in your daily diet. Vitamin B2 is a component of two enzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes are important in energy production.

Functions

Riboflavin’s functions include:

  • Assisting in energy production
  • Helping to synthesize normal fatty acids and amino acids
  • Helping the nervous system to function efficiently
  • Aiding in cellular growth
  • Assisting in the metabolism of certain other vitamins
Recommended Intake
Age Group (in years)Recommended Dietary Allowance
FemalesMales
1-30.5 milligrams (mg)0.5 mg
4-80.6 mg0.6 mg
9-130.9 mg0.9 mg
14-181.0 mg1.3 mg
19+1.1 mg1.3 mg
Pregnancy1.4 mgn/a
Lactation1.6 mgn/a
Riboflavin Deficiency

Riboflavin deficiency occurs as part of multiple nutrient deficiency states. Since riboflavin occurs in a wide variety of foods, deficiency symptoms are rare. Symptoms have been reported when daily riboflavin intake falls below 0.6 milligrams (mg). Symptoms of riboflavin deficiency include:

  • Cracks in the corner of the mouth (cheilosis)
  • Inflammation of the mucous membranes of the mouth
  • Sore or inflamed tongue (glossitis)
  • Reddening of the eyes
  • Eyes that tire easily, burn, itch, or are sensitive to light
  • Unusual skin inflammation (dermatitis) characterized by simultaneous dryness and greasy scaling
Riboflavin Toxicity

Riboflavin is relatively nontoxic. Although no adverse effects have been associated with high intakes of riboflavin from food or supplements, the potential may exist. Therefore, caution may be warranted with excessive amounts of riboflavin.

Major Food Sources
FoodServing sizeRiboflavin content
Beef, cooked3 ounces0.16 milligrams (mg)
Broccoli, cooked½ cup0.1 mg
Spinach, cooked½ cup0.21 mg
Milk, skim1 cup0.34 mg
Egg1 large0.27 mg
Whole grain bread1 slice0.06 mg
Health Implications
Populations at Risk for Riboflavin Deficiency

The following populations may be at risk for riboflavin deficiency and may require a supplement:

  • People who consume excessive amounts of alcohol
  • People with other nutrient deficiencies
  • People with anorexia nervosa
Prevention of Cataracts

Evidence that links riboflavin to the prevention of cataracts is unclear. Two large studies showed decreases in cataract rates in people over 65 years taking multivitamins, minerals, riboflavin, and riboflavin with niacin. Although the studies showed decreased risk of cataracts, the mixing of the vitamins made it difficult to tell which supplement caused the benefits.

Treatment of Migraine Headaches

Talk to your doctor about using riboflavin supplements if you have migraine headaches. In some adults, 400 mg per day may prevent migraines or reduce the number of migraine attacks.

Tips for Increasing Your Intake

To help increase your intake of riboflavin, include some dairy products in your daily diet. Milk, yogurt, and cheese are all good sources of riboflavin. Here are some other examples of foods with riboflavin:

  • Eggs
  • Almonds
  • Leafy green vegetables
  • Milk
  • Enriched cereal
  • Meats

Riboflavin is rapidly destroyed with exposure to sunlight. Therefore, foods containing riboflavin are best stored in a pantry, in bins, and, when perishable, in the refrigerator.