Understanding The Gut-Liver Axis: Overview
The gut-liver axis denotes the bidirectional relationship between the gastrointestinal tract and the liver, mediated primarily through the portal vein which is responsible for transporting nutrient-rich blood from the gastrointestinal tract to the liver. This axis is crucial for nutrient metabolism and the detoxification of harmful substances. However, disruptions in this system, often influenced by alterations in the gut microbiota and intestinal permeability, can contribute to sub-optimal liver function.
The Portal Vein & Blood Flow Circuitry
To appreciate how intestinal health impacts the liver, it is vital to understand blood flow circuitry between the intestines and liver:
The intestinal wall comprises several key components, with the innermost layer being the mucosa, which includes the epithelial lining, a layer of connective tissue called the lamina propria, and a thin layer of muscle known as the muscularis mucosae.
The epithelial lining is primarily made up of enterocytes which are cells that absorb nutrients from the intestinal lumen. Beneath the epithelial layer, the lamina propria is rich in capillaries and small lymphatic vessels. These capillaries are crucial as they collect absorbed water-soluble nutrients and other small molecules directly from the enterocytes. From here, the absorbed substances enter the venous circulation through venules, which coalesce to form larger veins. These larger veins are tributaries of the superior mesenteric vein and, to a lesser extent depending on their location in the intestine, the inferior mesenteric vein. The superior mesenteric vein collects blood from the small intestine and a portion of the large intestine, while the inferior mesenteric vein drains the lower part of the large intestine.
As these mesenteric veins exit the intestine, they converge and join with the splenic vein to form the portal vein, a critical blood vessel that channels nutrient-rich blood from the gastrointestinal tract directly to the liver. Within the liver, this blood disperses through a vast network of sinusoids, allowing hepatocytes to process and metabolize the nutrients effectively.
In summary, the portal vein is a vessel in the human circulatory system that plays a crucial role in transporting blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver. This vein is chiefly formed by the confluence of the superior mesenteric vein and the splenic vein, while including contributions from additional venous sources such as the inferior mesenteric vein, gastric veins, cystic veins, and pancreaticoduodenal veins. These tributaries collectively deliver a nutrient-rich and metabolite-laden flow to the liver, allowing it to metabolize absorbed substances, synthesize proteins, and conduct detoxification processes before these substances enter the general circulation.
Key Components Affecting the Gut-Liver Axis
The integrity of the gut epithelium and the composition of the microbiota are key players in maintaining the health and balance of the gut-liver axis. The gut epithelium acts as a barrier that regulates what substances can enter the bloodstream from the intestines. A healthy, intact gut epithelium prevents harmful substances like pathogens and toxins from escaping the gut and entering the liver via the portal circulation. However, when the epithelial barrier is compromised (increased intestinal permeability), these harmful substances can induce inflammation and damage in the liver. Additionally, symptoms of increased intestinal permeability often include digestive problems (bloating, gas, cramps), food sensitivities, chronic fatigue, skin conditions (eczema, acne), joint pain, and even the development of autoimmune diseases.
To expand on this notion, a key concern with increased intestinal permeability, in particular, is the translocation of bacteria and their products, such as lipopolysaccharides (LPS), from the gut into the portal circulation. LPS are potent inflammatory substances that can trigger a strong immune response. When LPS reach the liver via the portal vein, they can activate hepatic immune cells like Kupffer cells (liver macrophages). This activation leads to the release of pro-inflammatory cytokines and chemokines, which can induce liver inflammation.
For instance, a healthy gut barrier prevents most PAMPs (These are molecules associated with groups of pathogens that are recognized by the immune system's pattern recognition receptors (PRRs) and can trigger an innate immune response.) from entering the systemic circulation. However, if the barrier is compromised (e.g., due to inflammation, an underlying infection, or mechanical damage), it becomes permeable to substances like LPS and other bacterial products. These PAMPs can then translocate across the compromised gut barrier into the portal circulation.
Furthermore, with higher levels of harmful substances entering the liver, there is an increased burden on the liver's detoxification pathways. This can lead to oxidative stress and depletion of antioxidants within the liver. Over time, the liver's capacity to detoxify may be overwhelmed, impairing its function and health.
With That Said, How Can We Support the Gut-Liver Axis Through a Synergistic Approach?
Addressing Increased Intestinal Permeability
Assuming any underlying infections or GI pathogens (that could contribute to the increased intestinal permeability) have been addressed, what can we do to support the integrity of the gut lining and combat increased intestinal permeability? Several natural ingredients have been shown to be supportive of intestinal health: quercetin, a flavonoid, known for its ability to reduce gastrointestinal inflammation by stabilizing mast cells and lowering histamine production; bromelain, an enzyme derived from pineapple that enhances the absorption of quercetin and supports digestion; deglycyrrhizinated licorice (DGL), soothes and protects the gut lining; methylsulfonylmethane (MSM), essential for maintaining tight junction integrity; zinc orotate, critical for the structural stability of tight junction proteins; marshmallow root and slippery elm, both of which provide mucilage to coat and soothe the gut lining; aloe vera, known for its mucus-stimulating, anti-inflammatory, and antimicrobial properties; N-Acetyl Glucosamine (NAG), which supports the production of mucin; and glutamine, an amino acid that fuels enterocytes, promoting the repair and regeneration of the intestinal lining. These ingredients work synergistically to enhance intestinal health and combat increased intestinal permeability.
All of these ingredients are expertly formulated in "Leaky Gut Repair" from Liver Medic. I'm a very big fan of their formulation. They recommend 2 capsules in the evenings for maintenance, but I like to do 2 capsules in the morning and 2 capsules in the evening in order to really prioritize and protect the structural integrity of my gut lining.
Synergistically Supporting Liver Function
In addition to addressing any underlying intestinal dysbiosis and supporting the integrity of the gut lining... supporting healthy liver function can lend synergy to strengthening the gut-liver axis:
Selenium (L-Selenomethionine): Reduces oxidative stress by enhancing glutathione peroxidase activity.
N-Acetyl Cysteine (NAC): Boosts liver glutathione levels, crucial for detoxification.
Methylsulfonylmethane (MSM): Provides sulfur for glutathione synthesis.
Silybin (Milk Thistle): Promotes liver cell regeneration.
Turmeric (95% Curcuminoids): Helps to reduce liver inflammation by inhibiting NF-κB.
Berberine HCl: Helps improve liver metabolic function by activating AMPK.
Glutathione: Enhances liver detoxification and supports immune system responses.
Alpha Lipoic Acid: Aids in regenerating other antioxidants and boosts mitochondrial energy metabolism in liver cells.
All of these ingredients can be found in Liver Medic's synergistic Hepatiben supplement.
As a whole, Liver Medic's supplements also contain NO pesticides, NO residual solvents, and NO heavy metals. They're also gluten-free and allergen-free, ensuring you get only the best for your health. Â These supplements were strategically and uniquely formulated by Brendan Gaughran who is an extremely highly-regarded molecular biologist known for his contribution to gut health, liver health, the endocrine system, adrenal fatigue, and optimum diets.
Definitely go and check out these supplements and more at livermedic.com, and use code Chloe20 to get 20% off leaky gut repair.
*Always consult with a licensed medical professional for all of your medical needs and before taking any nutritional supplement.
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