Changes in Alanine Aminotransferase in Adults with Severe and Complicated Obesity during a Milk-Based Meal Replacement Programme

Abstract Introduction: Excess adiposity is associated with fat accumulation within the liver, and non-alcoholic steatohepatitis (NASH) is highly prevalent in bariatric patients. Elevated alanine aminotransferase (ALT) is associated with prevalent NASH. We sought to determine the influence of a milk-based meal replacement weight-loss programme on ALT levels in adults with severe and complicated obesity.Methods: We conducted a retrospective cohort study of patients who completed a 24-week meal replacement programme, comprised of a weight loss phase followed by weight stabilisation and maintenance phases, each eight weeks long. ALT was quantified using an enzymatic assay with spectrophotometric detection. We examined changes over time in ALT using the non-parametric Wilcoxon singed-rank test and the Friedman test.Results: Of 105 patients, 56 were female, mean age was 51.2±11.2 (range 18.0-71.6) years. There was an unanticipated but transient increase in ALT from 28.0 [20.0, 40.5] iu/l at baseline to 40.0 [26.0, 55.0] iu/l after two weeks (p<0.0005), followed by a gradual reduction to 21.0 [17.0, 28.3] iu/l by 24 weeks (p<0.0005). The overall reductions in ALT were more pronounced in patients who had elevated levels at baseline. Body weight decreased from 144.2±28.0 kg at baseline to 121.6±25.4 kg at 24 weeks (p<0.0005) and body mass index (BMI) decreased from 50.7±8.1 kg m-2 at baseline to 43.0±7.6 kg m-2 by 24 weeks (p<0.0005).Conclusion: In adults with severe and complicated obesity undergoing a milk-based meal replacement programme, there was an initial unanticipated rise in ALT in the first two weeks, followed by a gradual overall reduction by 24 weeks. These findings suggest that rapid weight loss secondary to significant caloric restriction might induce a transient deterioration in hepatic steatosis prior to an ultimate overall improvement.