Riboflavin deficiency is caused by a dietary lack of vitamin B ₂. It occurs when the chronic (long-term) failure to eat sufficient amounts of foods that contain riboflavin produces skin lesions, lesions of smooth surfaces in the digestive tract, or nervous disorders.

Riboflavin, also called vitamin B₂, is a water-soluble vitamin. The recommended daily allowance (RDA) is 1.7 mg/day for an adult man and 1.3 mg/day for an adult woman. The best sources of this vitamin are meat, dairy products, and dark green vegetables, especially broccoli. Grains and legumes (beans and peas) also contribute riboflavin to the diet. Riboflavin is required for the processing of dietary fats, carbohydrates, and proteins to convert these nutrients to energy. It is also used for the continual process of renewal and regeneration of all cells and tissues in the body.

Riboflavin is sensitive to light. For this reason, commercially available milk...