Iron status and iron supplementation in children with classical phenylketonuria

Iron (Fe) status and Fe supplementation were assessed in 20 children with phenylketonuria (PKU) through dietary intake and through measurements of ferritin, hematocrit, hemoglobin, mean cellular hemoglobin, mean cellular volume, serum Fe, total iron binding capacity, unbounded iron binding capacity, transferrin saturation and transferrin. Findings were compared to reference values and to data from age-matched controls. The prescribed phenylalanine-restricted diet supplied all the recommended nutrients. Dietary Fe was present in the diets, but its bioavailability is questionable as several laboratory results were not within accepted reference values. A ferrous sulphate supplement (5 mg elemental Fe/kg daily) was given for 120 days to a group of PKU children with lower Fe parameters, thus changing some of the parameters studied. Serum ferritin (p < 0.1), transferrin saturation and serum Fe (p < 0.05) increased after the treatment. The need for improved diagnosis of Fe status and determination of whether PKU children can benefit from therapeutic Fe is discussed.