Vitamin B2 (Riboflavin)

Requirements:

• RDA:
  
  1.2 - 1.6 mg.
  1.5 - 1.7 mg. for pregnancy and lactation
• Daily Optimal Intake
  
  5 - 15 mg.

Supplement Forms:

• Available individually and in B-complex

Labs:

• RBC glutathione reductase-FAD-effect

Food Sources:

• Almonds 1/4 cup (0.3 mg.)
• Beef heart 3 oz. (1.1 mg.)
• Beef kidney 3 oz. (4.1 mg.)
• Beef liver 3 oz. (3.6 mg.)
• Brewer's yeast 1 Tbl. (0.3 mg.)
• Brie cheese 2 oz. (0.3 mg.)
• Broccoli, cooked 1 medium stalk (0.4 mg.)
• Calf heart 3 oz. (1.2 mg.)
• Camembert cheese 2 oz. (0.3 mg.)
• Chicken liver 3 oz. (1.5 mg.)
• Milk, whole 1 cup (0.4 mg.)
• Rice, wild raw 1/4 cup (0.2 mg.)
• Roquefort cheese 2 oz. (0.3 mg.)
• Yogurt 1 cup (0.5 mg.)

Signs and Symptoms of Deficiency:

• Cheilosis
• Dry and scaly skin with itchy eyes that are sensitive to light
• Glossitis

Causes of Deficiency:

• Birth control pills
• Decrease of gastric acid
• Large amounts of caffeine
• Large amounts of theophylline (e.g., black tea)
• Saccharin
• Usually occurs with other B vitamin deficiencies

Adverse Effects and Toxicity:

• No known toxicity

Drug/Nutrient Interactions:

• Ascorbic acid may decrease bioavailability of riboflavin
• Tryptophanmay decrease bioavailability of riboflavin
• Copper may decrease bioavailability of riboflavin
• Zinc may decrease bioavailability of riboflavin
• Iron may decrease bioavailability of riboflavin
• Probenecid increases urinary excretion and decreases absorption
• Tetracycline increases urinary excretion of riboflavin
• Thiazide diuretics increase urinary excretion of riboflavin
• Thyroid medication decreases absorption
• Tricyclic antidepressants decrease absorption
• Riboflavin may prevent methotrexate from being taken into cancer cells

Biochemical Functions:

• Cofactor for enzymes related to ocular tissues
• Needed for glucose, fatty acid, and amino acid metabolism
• Needed for the Krebs cycle and electron transport chain
• Needed for the production of corticosteroids, erythropoiesis, gluconeogenesis, and thyroid enzyme regulation
• Needed to activate vitamin K, vitamin B6, folic acid, and niacin
• May help maintain tissue levels of reduced glutathione

Clinical Indications:

• Cataract prevention
• Depression
• Headaches
• Hypothyroidism
• Macular degeneration prevention
• Rosacea
• Schizophrenia
• Anemia

Copyright 1998 - 2008 by L. Vicky Crouse, ND and James S. Reiley, ND. All rights reserved (ISSN 1527-0661).