Riboflavin (vitamin B2) functions primarily as part of two coenzymes: flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). These coenzymes participate in oxidation-reduction reactions needed for the production of energy from glucose, amino acids, and fatty acids.

Signs of clinical deficiency include cheilosis (reddened and fissured lips), stomatitis (inflammation of the mouth), seborrheic dermatitis, anemia, glossitis (purple and swollen tongue), and neuropathy. Subclinical deficiency may produce symptoms such as increased sensitivity to light with loss of visual acuity, and burning or soreness of the lips, mouth, and tongue.

Riboflavin deficiency is almost always accompanied by deficiencies in other B vitamins, particularly niacin and pyridoxine. Athletes, alcoholics, and pregnant women are at higher risk for deficiency.

Riboflavin is widely distributed in small amounts in many foods. Milk and dairy products are the best sources.

No oral toxicity has ever been reported.

Additional Resources:

• Riboflavin - U.S. National Library of Medicine
• Riboflavin - Linus Pauling Institute
• Riboflavin - Wikipedia