Riboflavin, also known as vitamin B2, is a vitamin found in food and used as a dietary supplement. Riboflavin is one of vitamins of the group B.
The current estimated average requirements for riboflavin for women and men ages 14 and up are 0.9 mg/day and 1.1 mg/day, respectively, according to The Food and Nutrition Board of the U.S. Institute of Medicine.
Riboflavin is required as coenzyme in various flavoprotein reactions promoted by flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) .
The vitamin is essential for cellular respiration and for the mucous membranes of the gastrointestinal tract, a liver, the eyes, nerves, muscles and skin. Riboflavin is also crucial for the fetal development. Riboflavin is necessary for the absorption and activation of iron, folic acid, and vitamins B1, B3 and B6. The vitamin is involved in the hormone production by the adrenal glands.
Vitamin B2 is found in:
• milk and diary products;
• fish, meat and poultry;
• green vegetables (artichokes, avocados, parsley, broccoli, Brussels sprouts, spinach, dandelion greens, and watercress);
• whole-grain breads, enriched breads;
• almounds and nuts;
Causes and risk factors
Riboflavin as all of the vitamins in the group B is a water-soluble vitamin. Therefore the deficiency of riboflavin may occur if the intake of the vitamin with foods in not sufficient (a primary deficiency). Secondary deficiency develops when the body fails to absorb the vitamin or when the excretion of the vitamin is increased. To some extent the deficiency may also affect the elderly, women taking oral contraceptives, individuals with eating disorders, chronic alcoholism and those who suffer from various diseases such as HIV, inflammatory bowel disease, diabetes, chronic heart disease and kidney dialysis. Infants who undergo the phototherapy due to jaundice may also develop a riboflavin deficiency.
The women requires extra riboflavin during pregnancy and lactation. Recommended increased requirements for them are:
• Additional 0.1 mg/day in the first trimester;
• Additional 0.3 mg/day in the second and third trimesters;
• Additional 0.4 mg/day during lactation;
See also: Vitamin A deficiency
Riboflavin deficiency is characterized by the following symptoms:
• Weakness and fatigue;
• Throat swelling/soreness;
• Swollen, red, sore tongue due to inflammation;
• Skin cracking (cracked corners of the mouth – angular cheilitis) and seborrheic dermatitis;
• Skin dryness;
• Mouth ulceration;
• Skin rash (especially on the scrotum, vulva, and philtrum);
• Iron-deficiency anaemia;
• Blurred vision, night blindness and itching, sore, or bloodshot eyes;
• Cataracts and keratitis;
• Light-sensitivity and easily fatigued;
• Peripheral neuropathy;
• Weight loss;
• Malignancies (esophageal and cervical dysplasia).
Deficiency can be associated with some developmental abnormalities:
• Palate deformities;
• Physical development retardation in infants and children;
• Congenital heart defects;
To detect the deficiency of vitamin B2 red blood cell glutathione reductase activity may be measured.
Doses of riboflavin for deficiency treatment are the following:
• Age 3-12 years: 3-10 mg in tablets;
• Age >12 years and adults: 6-30 mg.