Dietary nutrients and biotics protect against injury to intestinal epithelial barrier in alcohol use disorder: A narrative review

Abstract

The intestinal epithelial barrier is anatomically and functionally distinct and specifically refers to the barrier formed by epithelial cells (enterocytes) and associated junctional complexes (tight junctions, adherens junctions, and desmosomes). The junctional complex is composed of specialized junctional proteins that regulate nutrient permeability across the gut epithelium while preventing passage of antigens, bacteria, and toxins. Modifying the junctional protein expression and disrupting the junctional complex structure result in intestinal hyperpermeability, referred to as "leaky gut." The leakiness promotes endotoxemia and systemic inflammation, which orchestrate metabolic diseases of multiple organs, notably the liver. Ethanol and its metabolite acetaldehyde, bacterial lipopolysaccharide (LPS), and neutrophil extracellular traps (NETs) deliver a four-pronged attack disrupting the gut epithelial barrier in alcohol use disorder (AUD). This article reviews the benefits of protecting the gut epithelial barrier structure and function in AUD. Adequate nutritional support is essential for maintaining the barrier integrity and sustaining gut health. Dietary nutrients and biotics supplements are effective in reinforcing the gut epithelial barrier integrity. Accordingly, this article elaborates on the prominent roles of dietary zinc, glutamine, and vitamin D supplementation in modulating the gut barrier junctional protein expression while mitigating the epithelial barrier breakdown induced by ethanol, acetaldehyde, LPS, and NETs. The efficacy of prebiotics, probiotics, and postbiotics in preventing disruption of the gut epithelial barrier in AUD is also reviewed. In summary, dietary nutrients and biotics supplements are beneficial in preserving the gut epithelial barrier integrity in AUD, thereby offering a supportive treatment option for alcohol-related diseases.