PKU patients on a relaxed diet may be at risk for micronutrient deficiencies

OBJECTIVE: To investigate micronutrient supply in phenylketonuria (PKU) patients on a relaxed diet.SUBJECTS/METHODS: Sixty-seven patients (6–45 years) with a phenylalanine tolerance X600mg/day were included in the study.From a 3-day diet record, protein supply as well as consumption of essential amino acids and several micronutrients wereassessed and compared with the current recommendations and data for the healthy population.RESULTS: Protein supply and consumption of all essential amino acids were sufficient in all patients. Supply of micronutrientsdepended on dietary regime. Patients with a total protein supply of 120% or more of the recommended amount and at least 0.5gprotein per kg body weight from amino-acid mixture (AAM) were sufficiently supplied with all investigated micronutrients.All patients without AAM supplement showed severe micronutrient deficiencies in their diet records.CONCLUSION: PKU patients under a relaxed diet are at risk of an insufficient nutrient supply, if they have first no substitution withAAM, second a protein supply less than 0.5g per kg body weight from AAM or third a total protein supply less than 120% of therecommendations. Therefore, close monitoring, specific dietary counseling and potential supplementation is mandatory to preventmicronutrient deficiencies in PKU patients.European Journal of Clinical Nutrition (2014) 68, 119–124; doi:10.1038/ejcn.2013.218; published online 20 November 2013Keywords: Phenylketonuria; relaxed diet; micronutrient deficiencies; micronutrientsINTRODUCTIONPhenylketonuria (PKU; OMIN 261600) is one of the most commoninborn metabolic disorders, with an incidence varying between1:3000 and 1:30000 across Europe.