Effect of walking exercise on liver enzymes in children with phenylketonuria and non-alcoholic fatty liver disease: A randomized controlled trial

BACKGROUND: Phenylketonuria (PKU), the inherited metabolic autosomal recessive disorder, is a prevalent disorder in Arabic countries (1 in 6000 babies are affected by this disorder) due to the high prevalence of consanguinity. In children with PKU, excess body weight and its associated complications - such as non-alcoholic fatty liver disease (NAFLD) - are highly reported due to the sedentary lifestyle, low physical activity, and restriction of the consumption of most important natural dietary proteins that can pose a potential risk of overconsumption of carbohydrates, sugars, and fats to meet children's energy needs. Investigating the effect of an 8-week walking exercise program on liver enzymes in children with PKU and NAFLD was the aim of this randomized controlled trial. METHODS: This PKU trial is a randomized controlled trial in children. Forty overweight/obese children with PKU and NAFLD who were aged 9-12 years old were included. Children were randomly assigned into an exercise group (n=20) that received an 8-week free walking program or control group (waitlist group, n=20). Serum alanine transaminase (ALT), body mass index (BMI), serum gamma-glutamyl transferase (GGT), serum triglycerides (TG), serum alkaline phosphatase (ALP), and serum aspartate transaminase (AST) were assessed in both groups. RESULTS: A significant enhancement (improvement) in BMI, ALT, GGT, ALP, AST, and TG was reported in the exercise group only. CONCLUSION: Participation in an 8-week free walking program significantly improves BMI, AST, ALP, ALT, GGT, and TG in children with NAFLD and PKU.