Riboflavin deficiency: conservation, manifestations, and assessment
THE CONTEXT
Riboflavin is centrally involved in lipid and carbohydrate metabolism. Its deficiency occurs in many countries but is not fatal because tissue riboflavin is efficiently conserved.
Conservation of riboflavin
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Riboflavin released during catabolism of enzymes is rapidly incorporated into newly synthesized enzymes.
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This efficient reuse explains why deficiency is not fatal despite riboflavin's central metabolic roles.
Clinical features
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Deficiency is characterized by cheilosis, desquamation and inflammation of the tongue, and seborrheic dermatitis.
Nutritional assessment
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Riboflavin nutritional status is assessed by measuring activation of erythrocyte glutathione reductase by FAD added in vitro.