Stimulation of erythrocyte glutathione reductase activity by flavin adenine dinucleotide (FAD) in Malaysian adults and newborns and their parents.

A study of glutathione reductase (GR) activity and its stimulation by flavin adenine dinucleotide (FAD) in erythrocytes of Malaysian newborns and adults of different racial groups showed that GR stimulation by FAD was greater than 20% in 50% of 866 newborns (57% of Malays, 55% of Indians and 41% of Chinese) and 54% of 274 adults (46% of Malays, 65% of Indians and 45% of Chinese). There was a significant negative correlation between GR activity and percentage FAD stimulation in both newborns and adults in all racial groups. Low GR activity and a high percentage FAD stimulation were more prevalent among parents of newborns with low GR activity than among parents of newborns with higher GR activity. Administration of riboflavin to mothers with low GR activity resulted in increased GR activity and a decreased percentage of FAD stimulation. None of the individuals examined had clear clinical manifestations of riboflavin deficiency. It is concluded that subclinical riboflavin deficiency leading to low GR activity is prevalent in Malaysia among adults and newborns, especially among Malays and Indians.