Background: The main treatment for phenylketonuria (PKU) is a low phenylalanine (Phe) diet, phenylalanine-free protein substitute and low-protein special foods. This study describes dietary composition and nutritional status in late-diagnosed adult patients adhering to a PKU diet.
Methods: Nineteen patients, followed at Oslo University Hospital in Norway, participated; median age was 48 years (range 26–66). Subjects were mild to severely mentally retarded. Food intake, clinical data and blood analyses relevant for nutritional status were assessed.
Results: Median energy intake was 2,091 kcal/day (range 1,537–3,277 kcal/day). Carbohydrates constituted 59% (range 53–70%) of the total energy, including 15% from added sugar; 26% was from fat. The total protein intake was 1.02 g/kg/day (range 0.32–1.36 g/kg/day), including 0.74 g/kg/day (range 0.13–1.07 g/kg/day) from protein substitutes. Median dietary Phe intake was 746 mg/day (range 370–1,370 mg/day). Median serum Phe was 542 μmol/L (range 146–1,310 mg/day). Fortified protein substitutes supplied the main source of micronutrients. Iron intake was 39.5 mg/day (range 24.6–57 mg/day), exceeding the upper safe intake level. Intake of folate and folic acid, calculated as dietary folate equivalents, was 1,370 μg/day (range 347–1744 μg/day), and resulted in high blood folate concentrations. Median intake of vitamin B12 was 7.0 μg/day (range 0.9–15.1 μg/day).
Conclusions: The diet supplied adequate protein and energy. Fortification of the protein substitutes resulted in excess intake of micronutrients. The protein substitutes may require adjustment to meet nutritional recommendations for adults with PKU.
Protein Substitute Nordic Council Natural Folate Nordic Nutrition Recommendation Dietary Folate Equivalent
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We thank Susan Jane Sødal for assistance with the English language. We also send our gratitude to the patients and carers who participated in the study.
Acosta PB, Yannicelli S, Singh RH, Elsas LJ, Mofidi S, Steiner RD (2004) Iron status of children with phenylketonuria undergoing nutrition therapy assessed by transferrin receptors. Genet Med 6:96–101PubMedCrossRefGoogle Scholar
Arnold GL, Kirby R, Preston C, Blakely E (2001) Iron and protein sufficiency and red cell indices in phenylketonuria. J Am Coll Nutr 20:65–70PubMedGoogle Scholar
Baumeister AA, Baumeister AA (1998) Dietary treatment of destructive behavior associated with hyperphenylalaninemia. Clin Neuropharmacol 21:18–27PubMedGoogle Scholar
Fitzgerald B, Morgan J, Keene N, Rollinson R, Hodgson A, and Rymple-Smith J (2000) An investigation into diet treatment for adults with previously untreated phenylketonuria and severe intellectual disability. J Intellect Disabil Res 44: t-9Google Scholar
Hanley WB, Feigenbaum A, Clarke JT, Schoonheyt W, Austin V (1993) Vitamin B12 deficiency in adolescents and young adults with phenylketonuria. Lancet 342:997PubMedCrossRefGoogle Scholar
Hvas AM, Nexo E, Nielsen JB (2006) Vitamin B12 and vitamin B6 supplementation is needed among adults with phenylketonuria (PKU). J Inherit Metab Dis 29:47–53PubMedCrossRefGoogle Scholar
Lee PJ, Amos A, Robertson L, Fitzgerald B, Hoskin R, Lilburn M, Weetch E, Murphy G (2009) Adults with late diagnosed PKU and severe challenging behaviour: a randomised placebo-controlled trial of a phenylalanine-restricted diet 1. J Neurol Neurosurg Psychiatry 80:631–635PubMedCrossRefGoogle Scholar
MacDonald A (2000) Diet and compliance in phenylketonuria. Eur J Pediatr 159(Suppl 2):136–141CrossRefGoogle Scholar
MacDonald A, Rylance G, Davies P, Asplin D, Hall SK, Booth IW (2003) Free use of fruits and vegetables in phenylketonuria. J Inherit Metab Dis 26:327–338PubMedCrossRefGoogle Scholar
McCaman MW, Robins E (1962) Fluorimetric method for the determination of phenylalanine in serum. J Lab Clin Med 59:885–890Google Scholar
Moseley K, Koch R, Moser AB (2002) Lipid status and long-chain polyunsaturated fatty acid concentrations in adults and adolescents with phenylketonuria on phenylalanine-restricted diet. J Inherit Metab Dis 25:56–64PubMedCrossRefGoogle Scholar
Nordic Council of Ministers (2004) Nordic nutrition recommendations 2004. Nordic Council of Ministers, AarhusGoogle Scholar
Rimestad AH, Borgejordet Å, Vesterhus KN, Sygnestveit K, Løken EB, Trygg K, Pollestad ML, Lund-Larsen K, Omholdt-Jensen G, Nordbotten A (2001) Den store matvaretabellen (The official Norwegian table of food composition), 2nd edn. Gyldendal Norsk Forlag, OsloGoogle Scholar
Robinson M, White FJ, Cleary MA, Wraith E, Lam WK, Walter JH (2000) Increased risk of vitamin B12 deficiency in patients with phenylketonuria on an unrestricted or relaxed diet. J Pediatr 136:545–547PubMedCrossRefGoogle Scholar
Rose HJ, White F, MacDonald A, Rutherford PJ, Favre E (2005) Fat intakes of children with PKU on low phenylalanine diets. J Human Nutr Dietetics 18:395–400CrossRefGoogle Scholar
Scriver CR, Levy H, Donlon D (2011) Hyperphenylalaninemia: phenylalanine hydroxylase deficiency. In: Valle D, Beaudet A, Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A (eds) The online metabolic & molecular bases of inherited disease. The McGraw-Hill CompaniesGoogle Scholar
Suitor CW, Bailey LB (2000) Dietary folate equivalents: interpretation and application. J Am Diet Assoc 100:88–94PubMedCrossRefGoogle Scholar
Ten Hoedt AE, de Sonneville LM, Francois B, Ter Horst NM, Janssen MC, Rubio-Gozalbo ME, Wijburg FA, Hollak CE, Bosch AM (2011) High phenylalanine levels directly affect mood and sustained attention in adults with phenylketonuria: a randomised, double-blind, placebo-controlled, crossover trial. J Inherit Metab Dis 34:165–171PubMedCrossRefGoogle Scholar
Trefz F, Maillot F, Motzfeldt K, Schwarz M (2011) Adult phenylketonuria outcome and management. Mol Genet Metab 104(Suppl):S26–S30PubMedCrossRefGoogle Scholar
Vugteveen I, Hoeksma M, Monsen AL, Fokkema MR, Reijngoud DJ, van RM, van Spronsen FJ (2011) Serum vitamin B12 concentrations within reference values do not exclude functional vitamin B12 deficiency in PKU patients of various ages. Mol Genet Metab 102:13–17PubMedCrossRefGoogle Scholar
Weetch E, MacDonald A (2006) The determination of phenylalanine content of foods suitable for phenylketonuria. J Hum Nutr Diet 19:229–236PubMedCrossRefGoogle Scholar
Yannicelli S, Ryan A (1995) Improvements in behaviour and physical manifestations in previously untreated adults with phenylketonuria using a phenylalanine-restricted diet: a national survey. J Inherit Metab Dis 18:131–134PubMedCrossRefGoogle Scholar
Yi SH, Kable JA, Evatt ML, Singh RH (2011) A cross-sectional study of docosahexaenoic acid status and cognitive outcomes in females of reproductive age with phenylketonuria. J Inherit Metab Dis 34:455–463PubMedCrossRefGoogle Scholar
Yi SH, Singh RH (2008) Protein substitute for children and adults with phenylketonuria. Cochrane Database Syst Rev CD004731Google Scholar