Riboflavin deficiency is known as pellagra, usually found in those who do not consume a diet rich in organ meats, leafy greens, and whole grains. It is seen in elderly, alcoholics, those with chronic liver disease, and those on total parenteral nutrition. Deficiency may be associated with severe lactic acidosis, especially in HIV patients on triple antibiotics. It also functions as an antioxidant. Riboflavin adsorption is decreased in hyperthyroidism.
Risk factors for vitamin B2 deficiency include the following:
Irritable bowel syndrome
Malabsorptive states (eg, celiac disease, small bowel resection, tropical sprue, inflammatory bowel disease)
Pregnancy and lactation (secreted in milk)
Inborn errors of riboflavin metabolism
Deficiency of riboflavin is not common in the United States because this vitamin is plentiful in the food supply. Symptoms of a severe deficiency include:
- Mouth or lip sores
- Skin disorders
- Sore throat
- Swelling of mucus membranes
- Growth failure
Because riboflavin is a water-soluble vitamin, leftover amounts leave the body through the urine. There is no known poisoning from riboflavin.