Gut Permeability Might be Improved by Dietary Fiber in Individuals with Nonalcoholic Fatty Liver Disease (NAFLD) Undergoing Weight Reduction

Abstract

(1) Introduction: Zonulin (ZO) has been proposed as a marker of intestinal permeability. Only a few studies have analyzed to date how diet influences the serum concentration of ZO among patients with non-alcoholic fatty liver disease (NAFLD). We performed a six-month dietetic intervention to evaluate the association between fiber intake and ZO concentration in 32 individuals with NAFLD. (2) Methods: Fiber content in the diet was estimated by Food Frequency Questionnaire (FFQ) and by analyzing 72-h nutritional diaries. ZO concentrations in serum were measured before and after the intervention by immunoenzymatic assay (ELISA). Fatty liver was quantified using the Hamaguchi score before and after the dietetic intervention. (3) Results: During the intervention, the dietary fiber intake increased from 19 g/day to the 29 g/day concomitant with an increase in the frequency of fiber consumption. All patients experienced significant (all p < 0.05) improvements in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGTP) activities. We also detected decreased serum triglycerides (p = 0.036), homeostatic model assessment insulin resistance (HOMA-IR (p = 0.041) and insulin content (p = 0.34), and improvement of fatty liver status according to the Hamaguchi score (p = 0.009). ZO concentration in serum decreased by nearly 90% (7.335 ± 13.492 vs. 0.507 ± 0.762 ng/mL, p = 0.001) and correlated with the amount of dietary fiber intake (p = 0.043) as well as the degree of fatty liver (p = 0.037). (4) Conclusion: Increasing nutritional fiber results in reduced serum ZO levels, reduced liver enzymes and improved hepatic steatosis in patients with NAFLD, possibly by altering intestinal permeability. Increased dietary fiber intake should be recommended in patients with NAFLD.

Diet Associations With Nonalcoholic Fatty Liver Disease in an Ethnically Diverse Population: The Multiethnic Cohort

“…Only few, smaller observational studies reported that patients with NAFLD consume fewer vegetables and less dietary fiber than controls . Randomized intervention studies have shown that fiber intake improves liver enzymes and noninvasive NAFLD scores among participants with NAFLD . We found a significant inverse trend between fruit intake and NAFLD, and a previous study showed that fiber from fruits has a favorable effect on liver enzymes among obese individuals .…”

Adipokines and Endotoxemia Correlate with Hepatic Steatosis in Non-Alcoholic Fatty Liver Disease (NAFLD)

“…Intestinal mobility has also been linked to the intestinal permeability, a potential cofactor in disease progression of NAFLD in both animal models and humans [24]. Consequently, dietary interventions focusing on increasing dietary fiber content were able to demonstrate a decrease in surrogates of intestinal permeability in patients suffering from NAFLD [25].…”

Risk factors associated with intestinal permeability in an adult population: A systematic review

“…Dietary intervention studies are limited; however, one study suggests an increase in dietary protein is associated with elevated zonulin and inflammation . Furthermore, it has been demonstrated that an increase in dietary fibre reduces zonulin . While alcohol withdrawal is associated with a reduction of IP with a greater result seen in patients with a high BMI .…”

“…84 Furthermore, it has been demonstrated that an increase in dietary fibre reduces zonulin. 85 While alcohol withdrawal is associated with a reduction of IP with a greater result seen in patients with a high BMI. 54 Based on these findings, dietary and lifestyle habits may present a key clinical feature that healthcare professionals may utilise in identifying patients at risk of altered IP.…”