Effect of dietary intervention, with or without co-interventions, on inflammatory markers in patients with nonalcoholic fatty liver disease: a systematic literature review

Abstract

Context 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. Objective This systematic review aimed to evaluate the effect of dietary interventions on cytokines and adipokines in patients with NAFLD. Data Sources 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. Data Extraction 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. Data Analysis 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. Conclusions 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.

Dietary Intervention Accelerates NASH Resolution Depending on Inflammatory Status with Minor Additive Effects on Hepatic Injury by Vitamin E Supplementation

“…An overall decrease in C-reactive protein, TNF-α and IL-6 and an increase in adiponectin levels, indicated an improvement in the inflammatory and possibly the oxidative status of NAFLD patients [61]. The authors suggest chronic inflammatory response in NAFLD/NASH as a putative therapeutic target area, and also propose inflammatory cytokines and adipokines as noninvasive markers of disease [61]. This is supported by previous studies showing a correlation between disease activity and serum TNF-α and adiponectin levels in children and adult biopsy-proven NAFLD patients warranting inflammation and oxidative stress as viable therapeutic targets of NASH [62][63][64].…”

“…In accordance, the introduction of a diet intervention in the present study resulted in a reduction in dyslipidemia, hepatic lipid accumulation and liver weight. A recent systematic literature review found that low-calorie diets improve the inflammatory profile in patients diagnosed with NAFLD [61]. An overall decrease in C-reactive protein, TNF-α and IL-6 and an increase in adiponectin levels, indicated an improvement in the inflammatory and possibly the oxidative status of NAFLD patients [61].…”

“…A recent systematic literature review found that low-calorie diets improve the inflammatory profile in patients diagnosed with NAFLD [61]. An overall decrease in C-reactive protein, TNF-α and IL-6 and an increase in adiponectin levels, indicated an improvement in the inflammatory and possibly the oxidative status of NAFLD patients [61]. The authors suggest chronic inflammatory response in NAFLD/NASH as a putative therapeutic target area, and also propose inflammatory cytokines and adipokines as noninvasive markers of disease [61].…”

Nutrigenetic Interactions Might Modulate the Antioxidant and Anti-Inflammatory Status in Mastiha-Supplemented Patients With NAFLD

“…Adopting a healthy lifestyle has been proposed as the cornerstone for disease management (8). Furthermore, dietary interventions aiming to improve the inflammatory profile have proven beneficial in patients with NAFLD (9). There is also growing scientific interest in a variety of supplements and herbal products, as potential therapeutic and/or preventive approaches for NAFLD (10,11).…”

Genetic Variants Associated with Non-Alcoholic Fatty Liver Disease Do Not Associate with Measures of Sub-Clinical Atherosclerosis: Results from the IMPROVE Study

“…NAFLD is characterized by lipid accumulation in the liver (hepatic steatosis) in the absence of alcohol consumption and increased circulating levels of the hepatic enzyme alanine aminotransferase (ALT). Hepatic steatosis has been associated with components of the metabolic syndrome (abdominal obesity, insulin resistance, hypertriglyceridemia) [7] and low grade systemic chronic inflammation [8], all factors known to predispose to the development of atherosclerosis in the vessel wall.…”