Quality of life aspects of a low protein diet using GMP in patients with phenylketonuria

Objective: To assess some quality of life (QOL) aspects of a low protein diet, using glycomacropeptide (GMP) as a protein substitute in patients with phenylketonuria (PKU). Methods: This was a multicentre, prospective observational cohort, study. Metabolic control, nutritional parameters, and dietary adherence were assessed in patients with PKU before (T0), and six months after (T6) starting a low protein diet using GMP. Selected items from the PKUQOL questionnaire were used to assess patients’ acceptance of their modified diet. Results: 18 patients from three Italian Centres, completed the study. With the exception of LDL-cholesterol and vitamin 25OH-D concentrations, there were no differences between T0 and T6 in metabolic or nutritional parameters. Data suggested that patients have a good acceptance of protein substitutes containing GMP, probably because of their improved palatability. Conclusions: According to our patients’ responses to items related to dietary regimen, GMP based protein substitutes do not appear to significantly affect QOL.