title: The effects of low carbohydrate diets on liver function tests in nonalcoholic fatty liver disease: A systematic review and meta-analysis of clinical trials.
abstract: BACKGROUND
  Although several observational and experimental studies have examined the effects of low carbohydrate diets (LCDs) on nonalcoholic fatty liver disease (NAFLD), there are considerable inconsistencies among studies. We summarized the effect of LCDs on liver function tests, including intrahepatic lipid content (IHLC), alanine transaminase (ALT), aspartate aminotransferases (AST), and gamma-glutamyl transferase (GGT) in patients with NAFLD.
  
  
  METHODS
  PubMed, ISI Web of Science, Scopus, and Google Scholar databases were searched for relevant publications until July 2014, resulting in ten relevant papers that were included in meta-analysis. Related articles were found by searching Medical Subject Heading terms of "NAFLD" in combination with "low carbohydrate". For this meta-analysis, we used mean differences and standard errors of liver function biomarkers. Summary effect and corresponding confidence interval (CI) were estimated using random effect models. Heterogeneity between studies was assessed using Cochran's Q- and I-squared tests.
  
  
  RESULTS
  Our search led to ten eligible papers that evaluated serum ALT levels (n= 238), nine reported serum AST levels (n= 216), five reported serum GGT concentrations (n= 91), and four assessed IHLC (n= 50). LCD decreased IHLC by -11.53% (95% CI: -18.10, -4.96;I2= 83.2%). However, the effect of LCD on liver enzymes was not significant. Mean differences for the effects of LCDs on ALT, AST, and GGT were -4.35 IU/L (95% CI: -12.91, 4.20;I2= 87.9%), -1.44 IU/L (95% CI: -4.98, 2.10;I2= 61.4%), and -7.85 IU/L (95% CI: -29.65, 13.96;I2= 99.4%), respectively.
  
  
  CONCLUSIONS
  LCD consumption in subjects with NAFLD led to a significant reduction in IHLC, but did not significantly affect the concentration of liver enzymes.
authors.affiliation: Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Community Nutrition, Students' Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Haghighatdoost
authors.affiliation: Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Department of Nutrition, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Amin
authors.initials: A
authors.lastname: Salehi-Abargouei
authors.affiliation: Department of International Health, John Hopkins School of Public Health, Baltimore, MD, USA.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Surkan
authors.affiliation: Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran; Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Azadbakht
keywords: Alanine transaminase; aspartate aminotransferases; glutamyl aminotransferase; liver fat content; low carbohydrate diet; nonalcoholic fatty liver