An integrative approach to maintaining a healthy gut


The role of the gastrointestinal tract in optimal function of an animal’s body is complex. Maximizing the function of the GI tract can help improve the overall health of patients.

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Integrative veterinary medicine, previously known as holistic or complementary and alternative medicine, is a newer approach to patient care. It “blends the use of conventional veterinary diagnostics and therapeutics with alternative diagnostic and therapeutic approaches that are validated by evidence,” noted Robert Silver, DVM, MS, adjunct faculty at Lincoln Memorial University.1

This approach can be used to treat disease in many organ systems and address systemic disease by focusing on a specific area of the body, such as the GI tract. At the recent Fetch dvm360® conference in San Diego, Silver discussed integrative approaches to gastroenterology that can improve and maintain the gut’s barrier function and improve overall patient health.

Beyond digestion: The role of the GI tract in maintaining health

“According to the principles of integrative medicine, the digestive tract is more than simply a means of deriving nourishment,” said Silver. It also plays a significant role in the immune system and is considered the largest organ of this system. This creates a “paradoxical double role of both needing to optimally absorb necessary nutrients, while at the same time excluding toxins, pathogens, and antigens,” according to Silver.

The GI tract has several defenses against pathogens, which include the following:

  • Barrier function, which is created by the 4-part mucosal barrier. Maintenance of this barrier requires healthy intestinal cells, normal liver function, and “good” bacteria, such as Lactobacillus acidophilus and L. bifidus.
  • Secretory function, which produce defensive proteins as part of the intrinsic immune system.
  • Digestive function, which denatures bacteria in the stomach due to the low pH of stomach acid.
  • Immune defenses provided by the gut-associated lymphoid tissue, which contains up to 60-80% of the body’s lymphocyte population.

When normal functions of the GI tract’s defenses are disrupted, such as with changes in intestinal permeability (“leaky gut syndrome”), antigens and toxins enter the body and lead to increased immune system activation. Over time, chronic pathology can develop secondary to ongoing inflammation and lead to chronic diseases that are both directly related to the gut, such food intolerances, food allergies, and inflammatory bowel disease, and in other body systems, such as atopy, asthma, chronic sinusitis, and arthritis.

Treating and preventing a “leaky gut”

Silver stated that “through the correction of defective barrier function, improvement, and even resolution of chronic conditions caused by or promoted by the hyperpermeable bowel can be addressed.” Treating leaky gut syndrome involves a 4-part strategy that Silver refers to as the 4-R program: remove, replace, repair, and reinoculate.

First, pathogens, allergens, and toxins are removed from the body. This will decrease immune system activation and lower the work of the liver in detoxifying the body. Antigens can be removed through elimination diets while antimicrobials may be needed to reduce pathogenic bacteria.

Next, the normal digestive factors that are absent or inadequate are replaced. With chronic hyperpermeability in the GI tract, pancreatic and intestinal enzyme production are decreased. This alters the level of digestion and ultimately the environment of the intestinal tract, which affects the population of commensal bacteria in the gut. Replacing these enzymes allows the restoration of a healthy GI tract environment.

Thirdly, the damaged intestinal mucosal barrier is repaired. This is done by decreasing bacterial translocation, increasing protein synthesis by enterocytes and providing antioxidants. Numerous compounds can play a role in this, including glutamine, lecithin, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), zinc and vitamin B5.

Finally, the GI tract must be reinoculated with normal microbial flora. These commensal bacteria can be disrupted by altered intestinal environments, antibiotics, H2 blockers, and hyperosmolar enteral diets. In health, they prevent overgrowth of pathogenic bacteria and contribute to maintaining the GI mucosal barrier. Silver notes that the normal microbiome varies throughout the GI tract. The use of prebiotics and probiotics can help to re-establish this normal microbiome, but the specific combination that is best will vary based on the individual patients’ normal flora.

Nutraceuticals that help restore healthy bowel function

Silver discussed several nutraceuticals that can help to achieve the 4-Rs, especially in helping to remove toxins. For example, montmorillonite clay can help to absorb toxins. In fact, Silver shared that recent research showed clay to kill methicillin-resistant Staphylococcus aureus.1 Additionally, calcium aluminosilicate (CAS) clay has been shown to resolve or improve diarrhea symptoms of patients receiving doxorubicin chemotherapy within 48-72 hours.2

Several nutraceuticals aid in removing toxins by supporting the normal liver detoxification systems. Some examples include1:

  • glucosinolates, which are phytochemicals found in cruciferous vegetables
  • epigallocatechin gallate from green tea and green tea extracts
  • milk thistle extract, which contains silymarin
  • N-acetylcysteine
  • Selenium
  • Folic acid
  • Vitamin E

Probiotic cultures can also help to restore healthy bowel function through many effects. They restore a normal pH through lactic-acid production, which promotes colonization by commensal bacteria. Additionally, the normal flora of the GI tract competes with pathogenic bacteria for nutrients and receptor binding sites. They also stimulate immunomodulatory cells, improve immune function, and can reduce diarrhea and gastroenteritis.

Finally, the free form amino acid I-glutamine supports the immune system and serves as fuel for cells in the intestinal epithelium. It has numerous beneficial functions in the GI tract due to its positive effect on protein synthesis and stimulation of lymphocyte function and immunoglobulin synthesis.

Take home points

Silver shared that a multimodal approach to improving gastrointestinal barrier function in veterinary patients will “strengthen digestive function, the immune system, and the body as a whole.” Understanding the role of the GI tract in maintaining systemic health is the first step in implementing an integrative approach to GI health. Treatments that remove toxins, replace normal missing digestive factors, repair the damaged intestinal mucosa, and reinoculate the normal flora should be selected from a combination of evidence-based traditional medical therapies and nutraceuticals.

Kate Boatright, VMD, a 2013 graduate of the University of Pennsylvania, is a practicing veterinarian and freelance speaker and author in western Pennsylvania. She is passionate about mentorship, education, and addressing common sources of stress for veterinary teams and recent graduates. Outside of clinical practice, Dr. Boatright is actively involved in organized veterinary medicine at the local, state, and national levels.


  1. Silver R. Integrative veterinary gastroenterology: principles and practices. Presented at: Fetch, a dvm360® conference; San Diego, California. December 2-5, 2021.
  2. Hahn KA and Carpenter RH. Calcium Aluminosilicate (CAS) in the Treatment of Intractable Diarrhea in Dogs with Cancer. Intern J Appl Res Vet Med; 2008;6(3)3181-3184.
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