ABSTRACT
Vitamin B-2 (Riboflavin) is a component of flavin mononucleotide and flavin adenine dinucleotide. The clinical manifestations of a riboflavin deficiency include cheilosis, glossitis, seborrheic dermatitis, corneal vascularization, photophobia, visual impairment, burning of the eyes, and pruritus. Clinical signs of a riboflavin deficiency and dietary intake of the vitamin have been shown to correlate with urinary riboflavin levels in controlled adult human studies. During pregnancy, urinary excretion of riboflavin has been reported to increase during the second trimester and fall during the third trimester. Red blood cell riboflavin is not a very sensitive index of riboflavin status due to the small magnitude of change noted with large variations in dietary riboflavin intake. Riboflavin nutritional status has been assessed through measurements of erythrocyte glutathione reductase activity coefficient, erythrocyte riboflavin concentrations, and urinary riboflavin excretion. Erythrocyte glutathione reductase is a flavoprotein which is sensitive to the riboflavin status of the subject.
