LOW RED-BLOOD-CELL GLUTATHIONE-REDUCTASE AND PYRIDOXINE PHOSPHATE OXIDASE ACTIVITIES NOT RELATED TO DIETARY RIBOFLAVIN - SELECTION BY MALARIA

This study was designed to confirm that low dietary riboflavin does no t contribute to the flavin-deficient red blood cells commonly found in subjects in Ferrara Province, northern Italy. In this area it is prim arily an inherited characteristic believed to have been selected for b y malaria, which was endemic from the 12th century. In parallel with a ssessment of daily riboflavin intake (DRI), flavin adenine dinucleotid e-dependent glutathione reductase (EGR) and flavin mononucleotide-depe ndent pyridoxine phosphate oxidase (PPO) were measured in beta-thalass emic heterozygotes, their normal relatives, and normal spouses (repres entative of the normal population). In all of these groups there is a high incidence of deficiency of these flavin enzymes. We found that th e majority had an adequate riboflavin intake and there was no signific ant correlation of EGR and PPO activities with DRI. Thus, interpretati on of low EGR activity is discussed with reference to studies of EGR d one to detect nutritional riboflavin deficiency in countries where the re is malnutrition and endemic malaria.