Evidence of riboflavin depletion in breast-fed newborns and its further acceleration during treatment of hyperbilirubinemia by phototherapy.

Phototherapy in the treatment of newborns with hyperbilirubinemia, resulting in degradation of bilirubin, also appears to have other photodynamic effects on metabolism. We studied flavin adenine dinucleotide (FAD) saturation of erythrocyte glutathione reductase, which should reflect riboflavin nutritional status, in 28 healthy newborns, and followed 37 newborns with hyperbilirubinemia prior to the start of and during phototherapy. The results indicate that healthy newborns on human milk feeding, relatively poor in riboflavin, have evidence of a transient riboflavin depletion soon after birth. This effect is made more pronounced by phototherapy and partially prevented by parenteral or oral administration of moderate amounts of riboflavin.