Macronutrients as Regulators of Intestinal Epithelial Permeability: Where Do We Stand?

Area of Science:

• Gastroenterology
• Nutrition Science
• Immunology

Background:

• Intestinal barrier function (IBF) is crucial for maintaining intestinal homeostasis and preventing disease.
• Alterations in IBF and intestinal permeability are linked to various intestinal and systemic conditions.
• Key components of IBF include the intestinal epithelium, tight junctions, mucus layer, secretory IgA (sIgA), and antimicrobial peptides.

Purpose of the Study:

• To review the regulation of intestinal permeability by starvation and macronutrients.
• To summarize current knowledge on how diet influences IBF.
• To highlight novel mechanisms regulating intestinal permeability.

Main Methods:

• Literature review of existing studies on intestinal barrier function, starvation, and macronutrient effects.
• Analysis of in vitro and animal model data regarding intestinal permeability.
• Synthesis of information on dietary components impacting IBF.

Main Results:

• Starvation and protein restriction can increase intestinal permeability, negatively affecting mucin, antimicrobial peptides, and sIgA production.
• Casein, protein-derived peptides, and glutamine show promise in reinforcing IBF.
• Dietary carbohydrates differentially affect permeability; nondigestible oligosaccharides (NDOs), including human milk oligosaccharides (HMOs), decrease it, while simple sugars increase it.
• High-fat diets are generally detrimental to IBF.

Conclusions:

• Macronutrients play a significant role in regulating intestinal barrier function and permeability.
• Specific dietary components like NDOs and certain proteins may offer therapeutic potential for IBF-related diseases.
• Further clinical studies are needed to validate findings and guide the use of macronutrients in managing IBF.