Abstract
The methods for the determination of protein requirements are reviewed and the difficulties in achieving the recommendations of the dietary management of phenylketonuria proposed by a Medical Research Council Working Party on Phenylketonuria using currently available low phenylalanine (Phe) protein substitutes and low protein foods are examined. These recommendations are that all infants whose blood Phe concentrations exceed 600 µmol/1 in the presence of a normal or low plasma tyrosine and an otherwise normal plasma amino acid profile while receiving a normal protein intake (2–3 g/kg/day), should start a low Phe diet immediately. Infants whose blood Phe concentrations remain persistently between 400 and 600 µmol/1 for more than a few days should also start treatment. The diet should contain a protein substitute which is Phe free (or at least very low in Phe) and otherwise nutritionally complete with a composition sufficient to provide 100–120 mg/kg per day of tyrosine and a total amino acid intake of at least 3 g/kg per day in children under 2 years of age. In children over 2 years the intake of amino acids should be maintained at a level of 2 g/kg per day. The protein substitute should be spread as evenly as possible through the 24 h. Blood Phe concentrations should be maintained between 120 and 360 µmol/1. In children aged over 10 years it is suggested that the protein substitute should supply the protein reference nutrient intake + 50%. An upper blood Phe limit of 480 µmol/1 rather than 360 µmol/1 may be acceptable in school age children. Adults and adolescents should continue treatment with the aim to maintain blood Phe concentrations no higher than 700 µmol/1. During the period before conception and during pregnancy women should aim to have plasma Phe concentrations between 60–250 µmol/1.
Similar content being viewed by others
Abbreviations
- MRC :
-
Medical Research Council
- Phe :
-
phenylalanine
- PKU :
-
phenylketonuria
- RNI :
-
reference nutrient intake
References
Acosta PB (1988) Availability of essential amino acids and nitrogen in vegan diets. Am J Clin Nutr 48:868–874
Acosta PB, Wenz E, Williamson M (1977) Nutrient intake of treated infants with phenylketonuria. Am J Clin Nutr 30:198–208
Allen JR, Humphries IR, Waters DL, et al (1994) Decreased bone mineral density in children with phenylketonuria. Am J Clin Nutr 59:419–422
Beaton GH, Chery A (1988) Protein requirements of infants: re-examination of concepts and approaches. Am J Clin Nutr 48:1403–1412
Bickel H, Gerrard J, Hickmans EM (1953) Influence of phenylalanine intake on phenylketonuria. Lancet II: 812–813
Bodley JL, Austin VJ, Hanley WB, Clarke JT, Zlotkin S (1993) Low iron stores in infants and children with treated phenylketonuria: a population at risk for iron-deficiency anaemia and associated cognitive deficits. Eur J Pediatr 152: 140–143
Cockburn F, Sherman JD, Ingall D, Klein R (1965) Effect of phenylalanine deficient diet on bone marrow and amino acid metabolism. Proc Soc Exper Biol Med 118:238–245
Committee on Medical Aspects of Food Policy (1977) The composition of mature human milk. Report of Health and Social Subjects No. 12. HMSO, London
Davidson LA, Lönnerdal B (1987) Persistence of human milk proteins in the breast fed infant. Acta Paediatr Scand 76:733–740
De Clue TJ, Davis J, Schocken DM, Kangas R, Benford SA (1991) Serum lipid concentrations in subjects with phenylketonuria and their families. Am J Dis Child 145:1266–1268
Department of Health (1994) Dietary reference values for food energy and nutrients for the United Kingdom. HMSO, London Report on Health and Social Subjects No 41
Feigen RD, Beisel WR, Wannemacher RW Jr (1971) Rhythmicity of plasma amino acids and relation to dietary intake. Am J Clin Nutr 24:329–341
Fomon S (1991) Requirements and recommended dietary intakes of protein in infancy. PediatrRes 30:391–395
Fomon SJ, Haschke F, Ziegler EE, Nelson SE (1982) Body composition of reference children from birth to age ten years. Am J Clin Nutr 35:1169–1175
Galli C, Agostani C, Mosconi C, Riva E, Salari PC, Giovannini M (1991) Reduced plasma C-20 and C-22 polyunsaturated fatty acids in children with phenylketonuria during dietary intervention. J Pediatr 119:562–567
Garlick PJ, McNurlan MA (1994) Isotopie methods for studying protein turnover. In: Räihä NCR (ed) Nestlé Nutrition Workshop Series, Vol 33. Raven Press, New York, pp 29–47
Heird WC (1989) Interpretation of the plasma amino acid pattern in low birth weight infants. Nutrition 5:145–146
Holt LE, Snyderman SE (1967) The amino acid requirements of children. In: Nyhan WL (ed) Amino acid metabolism and genetic variation. McGrah-Hill, New York, pp 381–390
Kindt E, Halvorsen S, Lie SO (1987) Does a marginal protein intake result in osteoporosis? J Inherited Metab Dis 10: 195
Kindt E, Lunde HA, Gjessing LR, Halvorsen S, Lie SO (1988) Fasting plasma amino acid concentrations in PKU children on two different levels of protein intake. Acta Paediatr Scand 77:60–66
Mills A, Tyler H (1992) Food and nutrient intake of British infants aged 6–12 months. HMSO, London
Miranda-da-Cruz BD, Seidler H, Widhalm K (1993) Iron status and iron supplementation in children with classical phenylketonuria. J Am Coll Nutr 12:531–536
Räihä NCR (1994) Protein requirement of healthy term infants during the first four months of life. In: Räihä NCR (ed) Nestlé Nutrition Workshop Series, Vol 33. Raven Press, New York, pp 153–164
Reilly C, Barrett JE, Patterson CM, Tinggi U, Latham SL, Marrinan A (1990) Trace element nutrition status and dietary intake of children with phenylketonuria. Am J Clin Nutr 52: 159–165
Report of MRC Working Party on Phenylketonuria (1993) Phenylketonuria due to phenylalanine hydroxylase deficiency: an unfolding story. BMJ 306:115–119
Report of MRC Working Party on Phenylketonuria (1993) Recommendations on the dietary management of phenylketonuria. Arch Dis Child 68: 426–427
Sherman JD, Greenfield JB, Ingall D (1964) Reversible bone marrow vacuolizations in phenylketonuria. N Eng J Med 270:810–814
Taylor LS, Scrimshaw NS, Young VR (1974) The relation between serum urea levels and dietary nitrogen utilization in young men. Br J Nutr 32:407–411
Walker AF (1975) Effect of high crude fibre intake on transit time and the absorption of nutrients in South American negro school children. Am J Clin Nutr 28:1161–1169
Wendel U, Ullrich K, Schmidt H, Batzler U (1990) Six-year follow-up of phenylalanine intakes and plasma phenylalanine concentrations. Eur J Pediatr 149:S13–16
World Health Organisation (1995) Energy and Protein Requirements. Report of a Joint FAO/WHO/UNU Meeting, Geneva: World Health Organisation. WHO Technical Report Series No. 724
Young VR (1990) Tracer studies of amino acid kinetics: a basis for improving nutritional therapy. In: Tanaka T, Okada A (eds) Nutritional support in organ failure. Excerpta Medica, Amsterdam, pp 3–34
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cockburn, F., Clark, B.J. Recommendations for protein and amino acid intake in phenylketonuric patients. Eur J Pediatr 155 (Suppl 1), S125–S129 (1996). https://doi.org/10.1007/PL00014228
Issue Date:
DOI: https://doi.org/10.1007/PL00014228