Abnormal feeding behaviours in phenylketonuria

Abstract

The strict low phenylalanine diet used in the treatment of phenylketonuria (PKU) may adversely affect feeding behaviour and nutritional status in PKU children. The feeding behaviour of 15 unselected PKU children (12 girls, 3 boys) aged 1–5 years (mean age 3 years) was studied. Each child was matched with an unrelated age‐ and sex‐matched non‐PKU control child. All the PKU children were on a strict low phenylalanine diet. The mothers of all the children completed a validated feeding assessment questionnaire examining maternal perceptions of the incidence and type of feeding problems, feeding behaviour and parental management. A scored video recording of each child eating a midday meal was made, and mothers recorded a 3‐day dietary assessment. Mothers of PKU children perceived their children to have more feeding problems than the mothers of the control children. They said that they were more likely to have a poor appetite (P<0.05), and have more gastrointestinal symptoms (P<0.05). The PKU group were more likely to be given their midday meal separately from the rest of the family (PKU group 67%, control group 20%; P<0.05), were less likely to start their meal without prompting (P<0.005) and received less parental feeding directed verbalization (P<0.05). Although there was no significant difference in energy intake between the two groups, the PKU group had a significantly lower weight z score than the control group: median (range) weight for age, PKU group z score −0.81 (−2.23 to 2.21); control group 0.65 (−0.81 to 1.83) (P<0.05), but no differences were noted for height z score. This study is the first to report on the extent of feeding difficulties in young PKU children. An awareness of the consequences of rigid diet therapy should prove helpful in improving management strategies.