Protein substitute dosage in PKU: how much do young patients need?
GROUND: The optimal dose of protein substitute has not been determined in children with phenylketonuria (PKU). AIM: To determine if a lower dose of protein substitute could achieve the same or better degree of blood phenylalanine control when compared to the dosage recommended by the UK MRC.(1) METHODS: In a six week randomised, crossover study, two doses of protein substitute (Protocol A: 2 g/kg/day of protein equivalent; Protocol B: 1.2 g/kg/day protein equivalent) were compared in 25 children with well controlled PKU aged 2-10 years (median 6 years). Each dose of protein substitute was taken for 14 days, with a 14 day washout period in between. Twice daily blood samples (fasting pre-breakfast and evening, at standard times) for plasma phenylalanine were taken on day 8-14 of each protocol. The median usual dose of protein substitute was 2.2 g/kg/day (range 1.5-3.1 g/kg/day). RESULTS: When compared with control values, median plasma phenylalanine on the low dose of protein substitute
