Non-Alcoholic Fatty Liver Disease in Overweight Children: Role of Fructose Intake and Dietary Pattern

Nutrients 2018 Sept 19; 10(9):pii E1329. doi: 10.3390/nu10091329 — Nier A, Brandt A, Conzelmann IB, et al. — Download PDF


  • To determine if the dietary pattern and lifestyle of overweight children without NAFLD differs from overweight children showing early signs of NAFLD.


  • Contrary to many other liver diseases, NAFLD is not a disease only found in adults, but, with a still increasing prevalence, is estimated to also affect 8% of normal-weight and up to 34% of overweight children and adolescents.
  • The underlying mechanisms related to the onset and progression of the disease are still not fully understood, and therapies other than lifestyle interventions are not yet available. However, results of epidemiological and clinical trials, as well as animal studies that analyze the role of diet in the development of NAFLD, as well as mechanisms involved, suggest that both general over-nutrition and a diet rich in certain macronutrients like saturated fat and/or sugars like fructose are critical in the onset of NAFLD.


  • A total of 92 overweight children, ages 5-9, were randomly recruited in primary schools, sports clubs, and kindergartens and were stratified by results of liver ultrasounds in overweight children with and without NAFLD. For comparison, data from 36 healthy normal-weight children reported in previously published studies was included in the study.
  • Laboratory measurements such fasting blood glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood lipid panels and serum uric acid were collected. Blood pressure was assessed and liver status was assessed via abdominal ultrasounds. Dietary intake was assessed via 24-hour recalls and data on sportive and sitting leisure time activity was also collected.
  • To determine if moderate dietary counseling, focusing only on parameters previously identified to be critical in the dietary pattern of overweight children with NAFLD, is an approach to improve the health status of overweight children with NAFLD, some of the overweight children with NAFLD were enrolled in a feasibility study. The primary aim of this intervention was to reduce fructose intake by ~50%.


  • Total caloric intake of overweight children with NAFLD was significantly higher than that of overweight children without NAFLD (~250 kcal/day). Total fat, protein, and fiber intakes were similar between overweight groups. However, total intake of carbohydrates was by trend higher in overweight children with NAFLD than in those without (~120 kcal/day, p = 0.06).
  •  While the intake of complex carbohydrates was similar between overweight groups, intakes of total fructose and total glucose (free fructose and glucose, respectively, as well as fructose and glucose derived from sucrose) were significantly higher in overweight children with NAFLD than in those without.
  • With the exception of cereal, in which consumption was higher among overweight children without NAFLD, the intake of food groups was similar between overweight groups. However, when further analyzing the amount consumed of the different food groups of those children reporting consumption of these foods, overweight children with NAFLD were found to consume significantly more sweetened beverages including soft drinks and fruit juices than overweight children without NAFLD. Intake of all other food groups was similar between groups.
  • Times spent with physical and sedentary activities were similar between overweight groups.
  • Unfortunately, due to the guardians’ unwillingness to participate in regular meetings, it was not possible to obtain valid data regarding nutritional intake and dietary pattern at the end of the intervention for the feasibility study.


  • Body weight, dietary pattern, and especially, the intake of sweetened beverages may be critical in the development of NAFLD in overweight children.
  • Targeting sugar or fructose intake even with moderate measures may be beneficial for overall health status of overweight children with NAFLD.
  • While there are many causes of NAFLD, the intake of fructose-containing sugars is likely to play a major role.

Points to Consider

  • In the present study, the sample size was quite small and participants were allowed to self-select their groups. The results are therefore subject to selection bias, and larger randomized studies are needed.
  • In this study, overweight children with and without NAFLD were not weight-matched and both groups included metabolically. Results might differ in larger and more homogeneous clinical studies.