How functional medicine, including the 5 Rs protocol for gut healing, effectively resolves leaky gut in dogs and cats.

Gut health is critical to a pet’s overall well-being.¹ Impaired gut function can impact an animal’s digestion, immune system, and behavior. Therefore, veterinarians must understand the factors leading to abnormal gut function, and how to restore the gastrointestinal system to optimal health.^2,7 This article provides a comprehensive guide to restoring gut health in pets by using nutritious whole foods and the principles of functional medicine.

The causes and manifestations of abnormal gut function, including intestinal permeability (also known as “leaky gut syndrome”), will also be described. The author outlines the “5 Rs” protocol for gut healing, which involves the five steps of removing, replacing, re-inoculating, repairing and rebalancing/reintroducing. The article also highlights the importance of using testing to guide therapeutic approaches to gastrointestinal issues, including leaky gut syndrome, as well as incorporating supplements (such as certain types of probiotics, fecal microbial transplant capsules, adsorbents, Chinese herbal formulas, and other individual and combination products) as part of a gut healing protocol.

INTRODUCTION

A comprehensive understanding of gut health requires a multi-faceted perspective, as many factors can contribute to abnormal gut function, including poor diet, medications, aging, and exposure to chemicals or other toxins. Accordingly, a multimodal approach to treatment that reflects the principles of functional medicine and incorporates an elimination and rotation diet, along with the use of selected supplements, can be a powerful tool to help restore gut health and thus prevent and/or improve chronic health issues. Hipocrates’ sage advice to let food be thy medicine is the underpinning of this approach.

FACTORS CONTRIBUTING TO ABNORMAL GUT FUNCTION

The digestive process starts well before food enters the mouth. It begins when the pet sees food, which leads to the release of ghrelin, a hormone that causes the animal to sense hunger. The production of insulin also begins in anticipation of a need to store the blood sugar that will increase from eating a meal. In the mouth, saliva lubricates the food and mechanical chewing breaks it down, making it easier to digest; saliva also has antimicrobial activity. When the chewed and partially digested food reaches the stomach, the stomach acid has several critical roles, which include breaking chemical bonds in the food molecules for more complete digestion, activating digestive enzymes in the stomach and small intestine, and destroying harmful bacteria.⁴

Various factors commonly disrupt optimal digestive function. For example, many pets who consume dry commercial pet food rarely chew and break down the food nuggets, placing an extra burden on the stomach and disrupting the digestive process. Some medications can reduce the production of stomach acid, which is crucial for supporting digestion and protecting against harmful bacteria. As pets age, their levels of digestive enzymes naturally decrease, making it more difficult for them to break down food in preparation for the absorption of nutrients needed by the body. Poorly absorbed nutrients can lead to health problems, including intermittent or chronic diarrhea.⁵

For these reasons, I recommend a nutritionally complete and balanced home-cooked diet for dogs and cats to support both the digestion of food and the absorption of nutrients. Cooking the food slowly at low temperatures provides the gastrointestinal system with the most easily digestible food and absorbable nutrients. Such “slow and low” cooking methods also prevent the creation of advanced glycation end products (AGEs), which form when certain foods are cooked at high temperatures. The accumulation of AGEs in the body negatively affects gut structure and function, causes inflammation, and damages other systems of the body.

Factors external to the body can also adversely affect the gastrointestinal system. The gluten protein found in wheat and the zein protein in corn can cause an inflammatory response in the gut that directly damages the enterocytes, causing severe gastrointestinal symptoms. Exposure to chemicals such as herbicides and pesticides can also alter the normal gut flora and disrupt essential gut functions.³

Furthermore, stress and anxiety can disrupt gut function by causing excess production of “fight-or-flight” hormones (such as cortisol), which can impact the gastrointestinal system in multiple ways. Chronic stress can lead to chronically elevated cortisol levels, wreaking havoc on the immune system, the production of normal hormones, and the gut flora. In particular, excess cortisol can lead to either over- or underproduction of stomach acid and/or gastrin (the hormone that stimulates the secretion of stomach acid). The production and release of digestive enzymes can also be markedly reduced due to elevated cortisol. Gut motility is affected by stress, leading to either diarrhea or constipation. Chronic stress can impact bile production and fat digestion, blood flow to the digestive organs, and the gut microbiome, leading to dysbiosis. An additional consequence of increased cortisol is compromised integrity and function of the intestinal barrier, leading to “leaky gut” syndrome.

Intestinal permeability, or leaky gut syndrome, occurs when a weakening of the tight junctions between enterocytes allows undigested food to be absorbed into the bloodstream and directly presented to the immune system, causing an inflammatory response in the gut. Leaky gut and the resulting immune response can lead to autoimmune diseases as well as the destruction of beneficial microflora in the gut, allowing pathogenic bacteria to take over. Additionally, leaky gut has been shown to precede IBS.⁶

RESTORING GUT HEALTH USING FUNCTIONAL MEDICINE

Functional medicine focuses on treating the root cause of health issues rather than simply treating the resulting symptoms. In the context of gut health, functional medicine aims to identify and remove factors contributing to intestinal permeability while also supporting and restoring optimal function of the gastrointestinal system.⁹

These aims are put into practice through the “5 Rs” gut health framework for restoring gut health,¹⁶ as mentioned above.

1. The first step is to remove any factors contributing to gut dysfunction, such as food allergens or toxins.
2. Next, we Replace these adversely contributing factors with healthy alternatives, such as fresh whole foods.
3. We then re-inoculate the gut with beneficial bacteria by using probiotic supplements and/or fermented foods that contain probiotics.
4. Following this, we Repair the gut using various supplements to create a seal from outside (the lumen of the intestine) to inside (the immune system, gut activated lymphoid tissue or GALT).
5. Finally, we rebalance lifestyle and reintroduce previously eliminated foods individually in order to identify specifically which foods are causing adverse reactions, and to understand what foods are now tolerated.

Each of these five steps is described in further detail in the following sections.

Step 1 – Remove

This essential initial step of the 5 Rs protocol involves removing all factors that contribute to intestinal permeability. This includes removing any foods a pet is sensitive or allergic to and replacing them with fresh whole foods. Please note the difference between the words “allergen” and “sensitivity”. It is estimated that 3.5% of dogs have true food allergies,⁸ while up to 32% of dogs presenting with signs of atopy have food sensitivities.⁸ Understanding this difference underscores the importance of healing the leaky gut so the immune system can stop responding to improperly digested food particles crossing through to the GALT, creating sensitivities. It is also important to avoid histamine-releasing foods, nightshade vegetables, and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), as each of these can irritate the gut lining.

Food sensitivity testing can be performed to help identify specific foods that may be associated with adverse effects in an individual pet, bearing in mind that all such tests are best considered a general “road map” rather than a definitive determination. In my practice, I have encountered false-positive and false-negative results in all types of food sensitivity tests, including tests that use blood samples, saliva, and hair/fur. Currently, I use a bioresonance test that uses saliva and hair/fur samples for food sensitivity testing; the benefits include the simplicity of sample collection by the pet owner at home, and a lower cost compared to other sensitivity tests. If food sensitivity testing is not feasible, an elimination diet is the alternative brute-force method for identifying foods that are potentially associated with an allergy or sensitivity. An elimination diet involves removing any specific protein (e.g. chicken, beef), carbohydrate (e.g. rice, potatoes), or fat (e.g corn or soybean oil) the pet has eaten within the past six months. This method requires thoroughly reviewing the ingredient listings for all foods, treats, supplements, etc. that the pet has consumed during this period. The elimination diet is typically continued for approximately two to three months, although the length may vary depending on the severity and duration of the pet’s symptoms.

Once potential food allergens and sensitivities have been identified (either by testing or an elimination diet), the next step of the 5 Rs protocol can begin. This subsequent replacement step builds upon the foundation of essential information gathered during the removal stage.

Step 2 – Replace

The replacement step includes developing a rotation diet designed specifically for the individual pet. This diet involves rotating on a regular basis (e.g. daily or weekly) the specific sources of protein, carbohydrate, and fat the pet is eating. The benefits of this strategy include giving the body a break from exposure to specific foods as the gut heals. The rotating periods of exposure to newly introduced foods help to prevent the immune system from developing an immune response to the new foods, thereby avoiding the emergence of additional sensitivities to the new foods being eaten. A rotation diet can also help more accurately identify foods that cause adverse reactions for the pet, and foods that are safe for the pet to eat.

To implement a rotation diet as a part of the 5 Rs protocol, three distinctly different diets (i.e. using different protein, carbohydrate, and fat sources as ingredients) should be designed, avoiding all foods to which the pet has a known or suspected sensitivity. Home-cooked diets are preferable for use in a rotation diet, as home cooking allows for complete control over the ingredients in the food, and also uses fresh whole foods that are less likely to contribute to intestinal permeability. If commercial foods are used, it is essential to identify products with ingredients that exclude all foods to which the pet may have an allergy or sensitivity. The pet should be fed a different diet every 24 hours, rotating among the three different diets. Treats should also be limited to the same ingredients included in the diet the pet is eating in a given 24-hour period. Simple treats can be made by dehydrating small amounts of the foods in the diet designated for the day. The rotation diet should be maintained for at least three to six weeks, or until the pet’s symptoms are completely resolved. In some cases, the removal and replacement phase of the 5 Rs protocol may extend up to 12 weeks.

Keeping a journal to track both the foods eaten, and any reactions that occur during the following two to three days, is strongly recommended during the use of a rotation diet. Notably, symptoms of a food sensitivity may not appear until up to 72 hours after the food is eaten. If the pet owner notices adverse reactions that are regularly associated with a particular diet, the individual foods included in that diet should be reassessed as possible sources of a food sensitivity and potentially removed from the diet.

I have found it helpful to introduce a spore-based probiotic supplement during the replacement step as soon as the pet’s symptoms have been reduced through an elimination and rotation diet. However, prebiotics should be avoided during the replacement step, as they can cause food sensitivity reactions.

Step 3 – Re-inoculate

Specific supplements, including probiotics, can be used to promote the restoration of gut health. The aim of probiotic supplements is to populate the gut with additional organisms that will support the scaffold of the gut microbiome and create a more hospitable environment in which the existing beneficial gut bacteria can thrive.¹⁰ Spore-forming probiotic bacteria can survive the harsh acidic environment in the gut and may colonize the intestines. Compared to non–spore-forming (or “regular”) probiotics, those that include spore-forming strains often have lower colony-forming unit (CFU) counts and contain fewer bacterial species. Dosing guidelines for these supplements should be followed carefully to ensure optimal results.¹

Another option for re-innoculaing the gut involves the use of fecal microbial transplant (FMT) capsules. These capsules, which contain freeze-dried stool specimens from healthy pets, can help restore gut health by introducing the correct species and a balanced variety of bacteria to the gut. Although the concept of a fecal microbial transplant may sound unappealing, this strategy has been shown to be effective in treating conditions such as inflammatory bowel disease and chronic diarrhea. With the commercial availability of FMT freeze-dried capsules, this has become a great option for pets with chronic long-standing disease. In my experience, however, before introducing FMT, it is critical to ensure the pet is eating a higher-fiber whole foods diet and that a foundational level of gut health has been achieved in preparation for supporting the addition of healthy microbes to the gut.

Step 4 – Repair

A variety of supplements has been demonstrated to be beneficial in supporting gut health and healing the gut barrier.

• Saccharomyces boulardii is a yeast that can help control diarrhea, improve gut barrier function, and stimulate the production of secretory IgA.
• boulardii also acts to modulate the microbiome and gut motility.
• Omega-3 fatty acids are a commonly-used supplement for supporting gut health, since their anti-inflammatory properties can help reduce inflammation, thereby improving gut barrier function and modulating the microbiome.^12,18
• L-glutamine and zinc carnosine are helpful for supporting gut health.
• Combinations of slippery elm bark, marshmallow root, aloe vera, and deglycyrrhizinated licorice are commonly found in supplement products developed to support gut healing.^13,14
• Lastly, certain Chinese herbal formulas, such as Si Jun Zi Tang (also known as Four Gentlemen), have been shown to be effective in supporting the Spleen (the organ associated with digestion in TCM) and improving gut health. The Four Gentlemen formula contains a combination of four herbs that work together to improve digestion and strengthen the immune system.¹⁵

Step 5 – Rebalance/ reintroduce

“Rebalance” refers to the idea that returning to the lifestyle that led to leaky gut will create it all over again. For humans, reducing stress, practicing meditation, having a good work/life balance, and making time for play are all recommended for preventing the recurrence of leaky gut and any symptomatology related to it.

How can we apply that to our pets? We know human stress levels and emotions impact our dogs.¹⁷ So stress management for dogs and cats begins with managing our own stress. Studies have shown the positive impact pets can have on the stress levels of humans.¹⁹ What if humans could minimize the stress levels of their pets by practicing mindfulness? A short three-minute period without the interruption of mobile devices, television and other distractors has been helpful for many clients with anxious pets. Daily exercise, especially outdoors, also provides environmental enrichment and stress reduction.^20,21

The reintroduction of previously eliminated foods can begin once all symptoms have resolved. This step is applicable if the pet owner wants to increase the number and variety of food ingredients included in their pet’s diet. However, this step is not essential and can be omitted. During this phase, it is critical to reintroduce foods individually, making note of any reactions that occur, and waiting at least 72 hours before reintroducing another food.²² If a reaction to a newly reintroduced food occurs, the reintroduction of another new food should not occur until at least 72 hours after the reaction has resolved. No further attempts to reintroduce the food that caused the reaction should occur for at least 18 months; if the pet again reacts to the food at that time, they will likely never be able to eat that food without experiencing a reaction.

USING TESTS TO IMPROVE GASTROINTESTINAL HEALTH

Testing can be a valuable tool for guiding strategies to improve gut health in pets.

Microbiome tests, which measure the quantity and diversity of microbes present in the gut, provide valuable information about a pet’s gut health and can help identify imbalances and/ or deficiencies in the microbiome. Microbiome tests involve extracting bacterial DNA from a stool specimen to determine which microbes are present; the quantities and types of microbes in the pet’s stool are compared to the microbiome profile of healthy patients to identify relative imbalances in any particular microbial species. This information can be used to make recommendations regarding the use of foods and/or supplements to better support a healthy microbiome.

As mentioned in the article, food and/or environmental sensitivity tests can provide helpful insights for identifying potential allergens or irritants that may be present in the pet’s diet or environment. Sensitivity testing can be performed on blood, saliva, or hair/fur specimens. These tests are particularly useful as a guide for making elimination and rotation diets more efficient and simpler to carry out.

Additional functional medicine tests can provide information on various factors, including digestion, nutrient absorption, detoxification, inflammation, and immune function and/or reactivity. Specifically, immune reactivity is often increased in patients with leaky gut syndrome, resulting from weakening of the tight junctions in the epithelial barrier between the gut lining and the bloodstream. Testing for markers of gut health (such as secretory IgA, zonulin, calprotectin, and pancreatic function) can help direct further strategies for supporting the patient’s gastrointestinal health.

Conclusion

Abnormal gut function, including leaky gut syndrome, can negatively impact a pet’s digestion, immune system, and behavior. Restoring and maximizing gut health is crucial for a pet’s overall well-being. A nutritious diet composed of whole foods can play a significant role in achieving optimal gut health. Additionally, by implementing the 5 Rs protocol for gut healing, and incorporating the use of testing and supplements, veterinarians can develop effective strategies to restore healthy gut function in dogs and cats. With the assistance of a veterinarian who applies these principles of functional medicine, pet owners can help ensure their furry friends live long, healthy, and happy lives.