Nutrient intake of treated infants with phenylketonuria.

Growth, energy, and nutrient intake of 88 treated infants in the Collaborative Study of Children Treated for Phenylketonuria were evaluated longitudinally and compared to normative data and by treatment group. Growth parameters (height and weight) did not differ according to treatment group assignment, nor did they differ from normative data. Subjects in treatment group 2 had a significantly higher intake of phenylalanine than did subjects in treatment group 1. Differences in intake of other nutrients disappeared when intake was compared on an energy or body weight basis. Differences in intake by males and females also disappeared when compared on an energy and a body weight basis. From none to 10% of the subjects had energy intakes below two-thirds of the 1968 Recommended Dietary Allowances (RDA). Low individual energy intakes were more commonly found in the first and fourth quarters, and only during the first quarter of infancy did mean energy intake meet the RDA. From 48 to 80% of subjects had intakes of preformed niacin below two-thirds of the 1968 RDA. Few subjects had low intakes of protein, iron, or vitamin A, and intakes of all subjects were greater than 67% of the RDA for calcium, phosphorus, thiamin, riboflavin, and ascorbic acid. It is suggested from the data presented that a supplemental casein hydrolysate supplies adequate essential amino acids and nitrogen to support normal growth in infants when protein and energy intakes are fed at the levels described.