PROTEIN-INTAKE AFFECTS PHENYLALANINE REQUIREMENTS AND GROWTH OF INFANTS WITH PHENYLKETONURIA

Growth and metabolic status of 25 infants with PKU were evaluated base d on protain intake. Food A-fed infants received a medical food contai ning 3.12 g protein equivalent per 100 kcal and Food B-fed infants rec eived a medical food containing 2.74 g protein equivalent per 100 kcal . Growth percentiles of infants in the Food A group were significantly greater than those for infants in the Food B group at 6 months of age (Food A percentiles: crown-heel length 55, head circumference 60, wei ght 73. Food B percentiles: crown-heel length 28; head circumference 2 9, weight 39). At study entrance, only crown-heel length of the two gr oups differed; Food B infants had a significantly greater mean crown-h eel length percentile (p < 0.05). Mean phenylalanine (PHE) intake was 38% greater by Food A-fed infants than by Food B-fed infants. Plasma P HE concentrations and mean energy intakes of the two groups did not di ffer. Mean protein intake of Food A-fed infants was greater during the first three months of life and significantly greater (p < 0.05) durin g the second three months of life than by Food B-fed infants. Mean pro tein intake 24% greater than Recommended Dietary Allowances (RDA) was associated with better PHE tolerance and growth than was found when me an protein intake was 9% greater than RDA.