Intestinal permeability: the most effective dietary supplements

The intestinal barrier is essential for human health; it allows the absorption of nutrients while preventing harmful substances from entering the body. This barrier, covering about 400 m², consumes nearly 40% of the body's energy expenditure. It is composed of an external physical barrier and an internal immunological barrier. Severe failure of this barrier can lead to systemic inflammation, increased intestinal permeability, and potentially multi-organ failure.rnrnIncreased intestinal permeability has been observed in various diseases such as Parkinson's disease, obesity, and type 2 diabetes.

Role of Intestinal Permeability in Diseases

New data suggest that the intestinal barrier and the gut microbiota play a role in many diseases. Indeed, increased intestinal permeability has been observed in several different conditions, such as Parkinson's disease, obesity, and type 2 diabetes.rnrnFor example, in inflammatory bowel diseases (IBD), the proteins that keep intestinal cells tightly connected are altered, allowing bacteria to cross the intestinal wall more easily; this is reflected by an increase in urinary secretion of specific markers. Similarly, in irritable bowel syndrome (IBS), a similar alteration of tight junction proteins is observed, increasing both paracellular and transcellular permeability, with bacteria crossing the intestinal wall more easily.rnrnIn celiac disease, the structure of tight junction proteins is modified, leading to increased absorption of gliadin, a wheat protein, as well as increased levels of zonulin, a protein that regulates intestinal permeability. Obesity is also linked to increased intestinal permeability, with dietary lipids inducing this increase and elevated levels of zonulin and lipopolysaccharide in the blood.rnrnType 2 diabetes also shows increased intestinal permeability, with elevated blood levels of lipopolysaccharide and zonulin, indicating an altered intestinal barrier. Similar trends are observed in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, where increased bacterial translocation and elevated permeability markers in the blood are detected.rnrnFinally, in major depressive disorder, markers of intestinal permeability, such as I-FABP (Intestinal Fatty Acid Binding Protein) and zonulin, are increased in the blood.

Intestinal Barrier and Regulation

The intestinal barrier is made up of epithelial cells linked by tight junctions that regulate the passage of molecules. Tight junctions include proteins such as claudins and occludin, which form complexes that connect cells to each other. In addition to this physical barrier, chemical substances, digestive secretions, and the gut microbiota also contribute to maintaining barrier function.rnrnBarrier homeostasis depends on the relationship between the gut microbiota and the epithelium. Factors such as diet, infections, toxins, and lifestyle can influence intestinal permeability. An imbalance in this relationship can have negative health consequences.

Nutritional Treatment Protocol

Human and animal studies have shown that supplementation with antioxidant nutrients and extracts prevents oxidative damage and helps restore normal mucosal barrier function.rnrn• Quercetin is a natural flavonoid with antioxidant, anti-inflammatory, and anticancer properties. It has been shown to improve intestinal barrier functions. Mast cells play an important role in the pathogenesis of intestinal mucosal inflammation and increased intestinal permeability. Quercetin helps control intestinal inflammation by inhibiting histamine release from human intestinal mast cells. It has also been shown to inhibit gene expression and production of pro-inflammatory cytokines. rnrn• Ginkgo biloba extract has antioxidant and free radical-scavenging properties with cytoprotective effects on gastrointestinal mucosal cells. Oral supplementation with Ginkgo biloba extract has been shown to reduce macroscopic and histological damage to the colon mucosa in vivo and significantly decrease pro-inflammatory cytokines in experimentally induced ulcerative colitis. Ginkgo has also been shown to prevent increases in intestinal permeability and mucosal injury associated with small intestinal ischemia in a dose-dependent manner in animal models.rnrn• Vitamins C and E play an essential role in protecting intestinal mucosal cells against oxidative damage and free radicals. In a clinical trial, oral supplementation with 300 mg of vitamin E decreased inflammation in the colonic mucosa of patients with ulcerative colitis. Another study in patients with IBD showed a significant decrease in vitamin C levels in mucosal tissues compared to non-IBD controls.rnrn• Zinc appears to play an essential role in maintaining normal intestinal permeability and controlling inflammation. Zinc deficiency has been shown to disrupt mucosal barrier function and increase the secretion of inflammatory mediators in human intestinal epithelial cells. Moreover, zinc has cytoprotective activity in the gastrointestinal tract and helps stabilize intestinal mast cells.rnrn• Probiotics help maintain or restore beneficial gut microflora and prevent or treat gastrointestinal disorders and associated systemic conditions. Probiotic supplementation may be beneficial in the treatment or prevention of IBD, irritable bowel syndrome, food allergy, atopic dermatitis, eczema, infectious diarrhea, antibiotic-associated diarrhea, chemotherapy-induced intestinal damage, and other diseases in humans.rnrn• L-glutamine is an important energy source for intestinal mucosal cells and is essential for the normal structure and functioning of the mucosa. Glutamine appears to be necessary for normal production of secretory immunoglobulin A (IgA) in the intestines. Secretory IgA are the most abundant immunoglobulins in external secretions and play a role in normal intestinal mucosal function as an immune barrier.rnrn• N-acetyl-D-glucosamine (NAG) is a natural aminoglycan present in high concentrations in intestinal mucus, secretory IgA, and other immunoglobulins. Intestinal mucus plays a crucial role in host protection by providing a mechanical and immunological barrier against toxins, antigens, and bacteria in the intestinal lumen. rnrn• Phosphatidylcholine is a component of human bile and a key component of the hydrophobic mucus that protects the gastrointestinal mucosa. Studies have shown that oral intake of PC can prevent intestinal injury and reduce permeability to intestinal endotoxins. rnrn• Polyunsaturated fatty acids support epithelial barrier integrity and normal mucosal permeability. Indeed, gamma-linolenic acid (GLA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) have been shown to be incorporated into the membrane phospholipid fraction of human mucosal epithelial cells and to reduce mucosal permeability defects caused by inflammatory cytokines.rnrn• Digestive enzymes: Adequate digestion is a necessary condition for normal gastrointestinal function and overall health. Deficiencies in digestive enzymes and imbalances in gastrointestinal pH can lead to impaired digestion that may contribute to nutrient malabsorption, food intolerance, food allergy, autoimmune diseases, bacterial overgrowth, and signs and symptoms of gastrointestinal discomfort. Insufficient pancreatic enzymatic activity can also lead to increased intestinal permeability.rnrn• Dietary fiber: Dietary fiber plays an important role in maintaining normal gastrointestinal function and health. Studies indicate that fiber helps maintain normal mucosal barrier function. Soluble fibers are fermented by colonic microflora, promoting the growth of beneficial bifidobacteria. Fermentation of dietary fiber by colonic microflora is the main source of short-chain fatty acids, including butyric acid, which is an important energy source for intestinal epithelial cells and plays a key role in colon homeostasis. Butyrate has been shown to inhibit inflammation, reduce oxidative stress, and maintain normal colonic mucosal barrier function.rnrn