Objective: Diet is the main component in the treatment of classical phenylketonuria (PKU). Living in the same house as a PKU patient affects the lifestyle of family members in many ways. The present study examines the dietary habits of the parents of PKU patients.

Methods: The parents of 32 PKU patients were asked about their socio-demographic characteristics, family dietary patterns (mealtimes; frequency of meals with the PKU patient; content of foods at mealtimes, etc.) the parental dietary regimen and any food allergies.

Results: The mean age of the PKU patients was 11.5±4.3 years, and 14 (44%) were female. The mean plasma phenylalanine (Phe) level over the previous year was 732.4±339.0 µmol/L in the patient group. Within the study sample, 2 (6%) families prepared only low-protein meals in the home, and the Phe levels of the two PKU patients in these families never exceeded >600 µmol/L, and 26 (81%) parents prepared separate meals for the PKU patient and for the other family members every day. The 28 (88%) parents had no special dietary regimen, with a mean Phe level of 774.8±345.4 µmol/L (p=0.055). Finally, 26 (81%) of the parents were careful about the foods they consumed while eating with the PKU patient, opting especially for foods that are low in Phe.

Conclusion: Diet is an indispensable part of the treatment of PKU and can affect the dietary patterns also of parents. Phe levels are lower in the children of parents who adopt a protein-restricted diet as a lifestyle, such as vegan and pescetarian. Large-scale studies are needed to investigate the physical, social and psychological effects of parents’ dietary habits on PKU patients.

Keywords: Phenylketonuria, mealtime, parents, phenylalanine, diet, family