1 Department of Rehabilitation, Nutrition and Sport, La Trobe University, Bundoora, Victoria, Australia.
2 Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia.
3 Department of Nutrition, Alfred Health, Prahran, Victoria, Australia.
4 Department of Gastroenterology, Alfred Health, Prahran, Victoria, Australia.
5 School of Allied Health, University of Limerick, Limerick, Ireland.
Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of liver disorders, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), with inflammation acting as a key driver in its pathogenesis and progression. Diet has the potential to mediate the release of inflammatory markers; however, little is known about the effects of various diets.
This systematic review aimed to evaluate the effect of dietary interventions on cytokines and adipokines in patients with NAFLD.
The electronic databases MEDLINE, EMBASE, CINAHL, and Cochrane Library were searched for clinical trials investigating dietary interventions, with or without supplementation, on cytokines and adipokines in NAFLD patients.
Basic characteristics of populations, dietary intervention protocol, cytokines, and adipokines were extracted for each study. Quality of evidence was assessed using the American Dietetic Association criteria.
Nineteen studies with a total of 874 participants were included. The most frequently reported inflammatory outcomes were C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), adiponectin, and leptin. Hypocaloric, isocaloric, or low-fat diets significantly (P < 0.05) lowered levels of CRP, TNF-α, and adiponectin. The addition of nutraceutical or pharmacological supplementation to dietary interventions appeared to elicit additional benefits for all of the most frequently reported inflammatory markers.
Hypo- or isocaloric diets alone, or with co-interventions that included a nutraceutical or pharmacological supplementation, appear to improve the inflammatory profile in patients with NAFLD. Thus, anti-inflammatory diets may have the potential to improve underlying chronic inflammation that underpins the pathophysiological mechanisms of NAFLD. In the absence of any known liver-sensitive markers, the use of cytokines and adipokines as a surrogate marker of liver disease should be further investigated in well-controlled trials.