Leaky Gut - a New Epidemic?

Carol Moreton • 23 June 2023
If you (or your horse or dog - my words, not the quote) had a form of joint disease, would you treat it as if you had allergies? Or EMS/diabetes?
Institute of Functional Medicine


You wouldn’t think so, would you. Yet these days we should perhaps be thinking that the answer to this is more of a Yes, because science is showing – and we’re becoming more aware - that there’s a growing epidemic that the gut is the hidden cause of most chronic disease. As we all know by now, everything starts with the gut, but these day I now say all over the website “ … but everything begins with the microbiome.”


One of the biggest roadblocks to perfect, smooth, functioning health is impaired digestive health. This is because without normal digestion, the body’s ability to absorb healing nutrients and remove toxins that disrupt homeostasis suffers greatly. What’s more, this very complex system is connected to every other system in the body. When digestion suffers, nothing works well.


What’s interesting is that leaky gut, also known as intestinal permeability, is not a new problem - in humans it’s long been associated with gastrointestinal diseases like Crohn’s and Celiac. There's also no doubt that leaky gut is a growing problem, and one that extends far beyond the gut - in humans it’s being linked with numerous serious health concerns including autoimmune and neurodegenerative diseases, including lupus, multiple sclerosis, rheumatoid arthritis, and Alzheimer’s.


* Edited to add (15.7.21) - Latest science is now showing that Glyphosate, the most prevalent - and highly toxic - agrochemical weed-killer used worldwide, is now thought to be directly responsible for increasing this widespread phenomenon of leaky gut, damaging the immune system and creating a systemic response of inflammation. See our Blog Post - Glyphosate - the latest data on its harmful effects


Researchers today are looking at how, in human health, leaky gut is a major cause of many chronic diseases and how it might be more common - and more harmful - than imagined. It's no surprise because basically, leaky gut means that the yukky undigested, toxic contents of the intestines have 'leaked' through the fragile intestinal wall membrane (the mucosa) into the bloodstream, and sent the immune system into a state of Red Alert panic. This epidemic affects us all, whether horse or human, even our dogs.


So, let's get the low-down on leaky gut.


Leaky gut explained

Leaky gut is basically about digestion gone wonky, and while some pre-digestion begins in the stomach/foregut, most digestion and absorption of nutrients occurs in the intestines, where the microbiome lives - multi-trillions of friendly microbes and not so friendly pro-inflammatory gut-damaging microbes, all (hopefully) living in reasonable harmony together and running the show.


When everything's functioning as it should, the cells that line the intestines, the mucosa, are linked securely together with tight junction proteins that create a barrier, and control what gets passed through into the bloodstream to fuel the body. Vital nutrients are let through, and foreign substances such as toxins are mostly kept out. Those that do slip through are swiftly tagged by the immune system with antibodies to signal white blood cells to get rid of them.


However, if this fragile mucosal lining is disrupted, the integrity of that protective barrier weakens and gaps/holes can develop. Cue intestinal permeability, and once that fragile intestinal lining has been compromised, undigested foreign proteins, and other food components not yet broken down by normal digestion, 'leak' through into the bloodstream in high concentrations. This is what’s commonly referred to as 'leaky gut'.


Sounds very unpleasant I know, and it's because it is - it needs to be taken very seriously. These foreign substances overwhelm the immune system and create an inflammatory response that leads to sgnificant health problems, not only in the digestive tract but throughout the entire body. Ultimately, a leaky gut has the potential to set the stage for a long list of systemic problems - it starts with symptoms that are easy enough to ignore, a bit of mild indigestion, maybe a bit of gas and bloating, but it then slowly progresses to intestinal misery - diarrhoea or worse, blockage, and loss of appetite.


Now we're heading towards a full-body crisis - loss of condition, fatigue/lethargy/brain fog, mood swings/anxiety, joint pain/arthritis, allergies, skin problems, hormone imbalances ... And one absolute guaranteed problem - a significantly weakened immune system leading to various autoimmune syndromes.


A whole ton of symptoms - because this is how interconnected gut health is with the rest of the body. If the gut's leaky, other chemical processes, organs, and tissues in the body won’t function well either.


How leaky gut happens

Okay, let's get to the nitty gritty. When we (whether human or horse) eat a meal, each chewed mouthful (bolus) passes from the mouth, down the oesophagus, into the stomach/foregut to be mushed about like the inside of a washing machine into a slime called chyme (ooh, get that rhyme 😎) and onwards into the small intestine, where the chyme works its way through the many miles of GI tract.


Finally, after digestion of the proteins, starches and fats, what’s left (the fibre) passes through to the large intestine/hindgut where the cecum and colons finish the job off, with the friendly fibre-digesting microbes fermenting the fibre, producing the energy source for our horse, and eliminating the waste out in neat little parcels. 😉


The small intestine is where the main digestive action - bar fibre - happens (via digestive enzymes), where nutrients are assimilated by the friendly gut microbes and then absorbed into the bloodstream to go fuel the body. It's a bit clever - the miles of intestinal walls are covered in tiny finger-like projections called villi, with each of these villi covered in even tinier fingers called microvilli - picture them as coral fronds waving gently in the ocean shallows. These villi and microvilli are where the nutrient-absorption action happens, along their own surface membranes. Clever little fronds.


That said, these nutrient absorbing, microscopic microvilli fronds are lined with just one - yes, that's just One - equally microscopic single row of cells (epithelial, if you're interested), collectively known as the mucosa. This literally means that the only protection between the body and the yukky contents of the small intestine is just One-Microscopic-Cell thick. So vulnerable! Yet an utterly crucial part of the gut system, being that it's the absolute master nutrient-absorption area. That said, one microscopic cell isn’t exactly much protection against yukky, dangerously toxic, undigested poisonous matter.


So what protects this exposed yet critical component of the gut system?

Simples - a beautiful, beneficially reciprocal relationship between the gut microbiome and the immune cells, that’s what. As in, the friendly bacterial microbes, because inside the GI tract are multi-trillions of bacteria made up of hundreds of thousands of different species, including a motley crew of viruses, yeasts, amoeba and other parasites, all working together. Collectively, they’re the microbiome.


Most of this microbial population are commensal bacteria, which in Latin roughly means “to eat at the same table”. Which is a good way to look at them as it simply means that the commensal bacteria eat the same foods as the host does, especially fibre, regardless of whether we’re human, horse or even dog.


(Quick digress – I got my own microbiome tested in 2019 and the results came back saying my friendly gut bugs were (quote) ‘veggie munchers’; quirky, cos I’m a vegetarian, not necessarily by choice (although I'm happy to be) but because we discovered back in my teens that my gut, literally, struggles to digest meat, aka, wrong-kind of microbes. 😉)


This is one reason why fibre is such an important part of the diet, even for dogs. Fibre from fruits, berries and veggies feeds the commensal bacteria communities, and in return, they produce digestive enzymes to break down the food nutrients into amino acids, fatty acids et al.


Commensal bacteria are considered not only beneficial for their digesting abilities, but provided there’s enough of them, they also help protect against the pro-inflammatory, pathogenic bacteria - the bad guys - by competing for food and the best places to live in the gut. Provided the gut biome/flora environment is in balance, there’s a beautiful co-operative going on as they all function in harmony together - as long as the bacteria stay in the gut.


Luckily, the commensal bacteria don’t actively cross the one-cell intestinal membrane barrier. And this is important, because if they did, this would trigger the immune system into battle. And that would cause systemic inflammation.


The leaky-gut/immunity connection

The body’s immune cells work carefully with the commensal bacteria to make sure they don’t break through the barrier and force the immune cells to respond and trigger inflammation in the body. This is why there’s a high % of immune cells in and around the gut system, around 70-80%-ish, and it’s these immune cells that physically protect the delicate border between the gut contents in the small intestine, and the bloodstream and organs on the other side.


However - we know gut inflammation can happen because leaky gut exists. While the intestinal wall cells normally work together like a tight zipper, if there's more of the bad microbes than the friendly microbes, especially lactic-acid bacteria, they release lactic acid gas which blows up the small intestined like a balloon - gas has no place in the thin tube that is the small intestine - and the pressure tears open the zipper-like junctions between the cells. Cue a permeable gut lining, aka leaky gut.


Result? Warfare. One Almighty-Immune-Response that triggers chronic inflammation in the entire body. This leaky gut-related inflammation is the driver of most chronic diseases known in humans - dementia, autoimmune disease, heart disease, diabetes, arthritis, liver/kidney disease, cancer, IBS, allergies … all can be caused by leaky gut, with thousands of studies over the last decade looking at the role leaky gut plays in well-recognised established health issues.


The blame-game

  1. Top of the list, and you've guessed it - an unnatural diet. Never mind the way us humans eat; the way we feed our domesticated horses here in the UK barely comes close to resembling the diet that evolution designed the equine gut to eat over millions of millenia. Grazing on our totally wrong type of neon-green leaf-blade grass, full of grass sugars, pectins and zero fibre, alongside the sheer volume of highly processed feedbags for a feedbowl that's been cultivated for convenience instead of species-appropriate, does not a healthy gut make. Great news for the pro-inflammatory bad gut microbes though, as, as their favourite food is undigested carbs and sugars.
  2. Non-stop stress - some stress comes with the territory, bringing on a temporary fight/flight response - a biological throwback to run from the sabre-toothed tiger. But ongong, chronic stress tells the body that there's a tiger hot on the heels all day long. The fight/flight stress hormones drag the body's badly needed energy and resources solely into the brain and muscles, which results in digestion being switched off, slowing the movement of food through the gut and leaving it sitting, rotting, in the GI tract - no surprise that this compounds the problems associated with leaky gut.
  3. Gut-disrupting toxins - toxins can enter the body via three routes; ingested,i.e. artificial chemical treatments on feed as well as mycotoxins from mould spores; through breath - i.e. air pollution, crop spraying, pollens; finally there's pharma drugs which disrupt the microbiome, and antibiotics which kill it off.


All these disrupt the cell membranes, acting like free radicals and causing serious inflammation. This in turn compromises the immune system, disrupts homeostasis, and allows bad bacteria to flourish and upset the balance of the microbiome.

Arguably the most common symptom of leaky gut looks a lot like allergies, because an allergic response is considered an autoimmune response, and leaky gut is thought to be the cause of autoimmunity.


But now let's bring proteins into the mix - if the gut is permeable, undigested proteins will leak out before they’re digested, and this is a problem because …


The immune system recognises foreign invaders by their proteins, so when it sniffs a protein in the body where it wouldn’t normally be, i.e. a viral or bacterial protein, the immune system would attack it as a matter of course. It would then file away the information about the protein in memory cells, which make sure that the immune system will quickly recognise and destroy that same invader if it comes back.


Which means, leaked food proteins can trigger the same immune response that bacteria and viruses would, thanks to those undigested food proteins leaking though the gut wall. Cue food intolerance, aka hypersensitivity.


If the microbiome is in good shape and the small intestinal gut membrane is zipped up, proteins from food won’t pass through the gut lining until they’re digested, where they’re broken down into small units called amino acids. The body won’t suffer the same immune consequences because the proteins have first been dismantled into their respective parts. But if they leak through ...


Food intolerance is one of the biggest signs of leaky gut, but there’s more. Because leaky gut triggers an immune response in the entire body, it can be hard to detect, but common signs include:


  • Autoimmune disease
  • Arthritis and joint pain
  • Allergenic responses
  • Skin issues
  • Digestive issues – any abnormal change means gut disruption
  • Liver, kidney, pancreas
  • Aggression/anxiety
  • Thyroid issues (and in turn, thyroid issues can worsen leaky gut)


The signs are varied because the chronic inflammation leaky gut causes can affect any (or multiple) organs - it’s truly a whole-body issue. It also shows that leaky gut is much more common than scientists first believed, and potentially more disastrous for all of us.


Since a large percentage of us, our horses and dogs, have one or more of these health issues, let’s look at the causes of leaky gut. If one or more of these apply, there’s a good chance it’s down to leaky gut.

Thing is, though, there are two problems with diagnosing leaky gut.


  • First, there isn’t really a standard diagnostic test for detecting leaky gut syndrome. Vets can carry out stool culture evaluations, or take bloods to evaluate the functional capacity of the liver; I believe there's also a hypersensitivity check for unusual proteins in the blood, but it may come back with a sensitivity to most proteins. This could mean leaky gut because it means the immune system is reacting to pretty much everything that leaks through, but if there’s only sensitivity to one or more proteins, it doesn’t necessarily mean it's leaky gut. I've had clients tell me their vet has said their horse has an 'infection' in the gut, and usually prescribes antibiotics, which only make the problem worse.


  • Secondly, leaky gut can cause many other diseases. A GP or vet will treat the resulting symptoms with chemical pharma meds, but more than likely this will only makes the leaky gut worse because the body has to metabolise those chemicals, on an already overburdened body.

Perhaps the best way to determine if there’s leaky gut is to look at the stressors the gut system’s been exposed to, i.e.:


  • Antibiotics – which wipe out the entire microbiome.


  • Drugs - i.e. NSAIDs, vaccines, steroids, antihistamines, vet meds etc.


  • Stressors – chronic long-term stress basically shuts the gut function to Off, while releasing its own toxicity residue.
  • Yeast overgrowth.


  • Age – as we all age, the number and diversity of gut bacteria start to decline.


  • Glyphosate - bit of a nasty one, this, glyphosate being a herbicide that’s also antibiotic. Unless you’re feeding organic, if there’s local crop spraying to you, or if your field is fertilised or sprayed with anything, i.e. to kill off docks or thistles, there’ll be glyphosate. If there are grains or legumes (alfalfa) in the diet, again unless they’re organic, again there’ll be glyphosate - the ingredients with the highest glyphosate content include oats, wheat, soy, potatoes and legumes (chickpeas, peas, lentils, beans and peanuts). Glyphosate is also found in most grains - unless they're organically grown. As earlier (as at 15.7.21), see our most recent Blog Post on the latest glyphosate revelations.


  • Lectins - lectins are natural proteins in plants that act as a defence mechanism against predators. Which is fair enough – plants have every right to defend themselves, but when we eat the plant, those lectin proteins attack the mucosal lining of gut. Beans, peas, soybeans, lentils and other legumes have the highest lectin content of any food group, as do members of the nightshade family, i.e. peppers, potatoes and tomatoes. Lectins are also found in most grains with the exception of sorghum and millet. For us humans at home and especially if you’re a veggie, if you’re soaking legumes, i.e. chick peas or kidney beans, add a slosh of ACV in the soaking water as this helps to break down the lectins.


  • Gluten – as well as us humans, many dogs are gluten-sensitive. When we eat foods with gluten, the small intestine produces zonulin, a chemical that signals the tight junctions of the intestinal walls to open up, creating permeability.


  • Mycotoxins - mycotoxins are cancer-causing moulds that grow on grains, legumes and other starchy plants. They’re found in many processed pet foods; Purina has been quoted as referring to them as an “unavoidable contaminant.” Hmmn. Perfectly avoidable if you feed raw. Not unsurprisingly, mycotoxins have been shown to increase intestinal permeability in most species.


  • Dairy - whey and casein are proteins in milk that can also cause gut inflammation, so be aware if you're feeding a whey protein to your horse. Both casein and gluten share a similar molecular structure and 50% of people who are gluten-intolerant are also casein-intolerant. Sheep/goats have a different type of casein, which could make them easier to tolerate, but they're still high in lactose. Most dogs don’t produce the enzyme lactase, which is needed to digest the lactose in dairy products, so if your dog is eating kibble or has a dairy sensitivity, then there could be leaky gut.


Supporting a Leaky Gut

The first step is to try and eliminate, as best you can, any or all of the contributing factors you have control over that cause gut inflammation – gut-disrupting foods, chronic stress, and toxins – and monitor to see if there's any improvement. It's a bit do-or die really - if we don’t eliminate the causes of leaky gut, the leaky gut will never resolve, and neither will the health issues it creates.


  • Stop all drugs and antibiotics (it might be time to upgrade to a holistic or homeopathic vet).



  • Remove stressors, as the stress hormones themselves not only disrupt then shut gut function off, but release their own buffet of toxicity side effects.


Now to supplements and foods that can help repair the gut lining and reduce gut inflammation:


The Leaky-Gut Fix-Kit - Weed, Feed & Seed

It’s imperative to regenerate the friendly gut biome colonies to crowd out the pro-inflammatory, gut-damaging pathogen bacteria, in order to rebalance the gut microbiome and the immune system.


  • Weed It - weed out the bad stuff. Remove all processed, C.R.A.P.* feeds from shiny feedbags piled high in our feed merchants, which are filled with molassed-laced, poor-quality, pointless fillers (oatfeed/wheatfeed, cereals, grains, corn, soya etc etc etc), mostly chemically treated with numerous toxic sprays, including glyphosate, as well as being GM. In other words, all typical feedstuffs that have shifted our equine world over the last half-century towards an exploding disease state. And all cheaper than a bag of shavings, so how can that be healthy? See our Why what we feed has to be right/The Feedbowl page.⁣


  • Feed It - feed biologically species-appropriate, real food, high in diverse, multi-species soluble fibre, preferably organic to avoid the toxic chemical saturation from all the growth treatments the non-organic agri-crops have been sprayed with. See the What I feed page. ⁣


  • Seed It - plant the seeds for more of the friendly hindgut fibre-fermenting microbes, with wonderful prebiotic fertiliser, aka equine-gut-appropriate fibre from long, stemmy, coarse forage roughage, i.e. hay, hay, more hay and only hay. The stems are where the magical cellulose fibre is - this feeds the friendly microbes who give back important nutrients - postbiotics - and the energy source for our horse. The more fibre we give to the friendly hindgut fibre-fermenting microbes to do their thing on, the more we're sowing friendly microbe seeds in our microbiome, because the happier they are, the more they'll multiply, and keep the bad guys out.


So, here's the Fix-Kit:


  • Feedbowl - Personally I love the Agrobs' brand - their Weisencobs/WeisenFlakes or any of their chaffs. We need fibre diversity in the gut - remember the paddock of thirty-years or so ago with 30-40 different plants and grasses? Agrobs blend over 50 different grasses and natural herbage, all grown using organic practices.


  • For the dysbiosis - a 1-month course of our SIBO-CARE blend.


  • Repairing the gut membrane - See our GutAminos, a combo of two vital amino-acids for the cellular membrane protein repair, specifically L-Glutamine with N Acetyl L Cysteine (NAC) which is is the precursor to the body's master antioxidant, Glutathione. L-Glutamine is an important part of resolving leaky gut because it’s the preferred food of the cells lining the gut wall, so it helps with their growth and repair. L-Glutamine also supports the mucosal lining in the gut and can help maintain the right pH balance. It’s so important to gut health that low concentrations are linked to gut permeability and inflammation. For us humans L-Glutamine is found naturally in spirulina, broccoli and asparagus, but when leaky gut is present, it should be also be supplemented separately.


  • Leaky gut/SIBO hurts - you would have likely seen gut flinching, biting, head swinging back to the hindgut, maybe even cow-kicking. In extreme cases, alleviate with our TriBute alongside our SIBO-CARE for 7-days; then continue with our DuoBute.


Extra support

  • Aloe Juice - used medicinally for over 5,000 years, Aloe Vera juice comes from the inner fillet of the leaf, not the harmful latex or outer leaf. Aloe Vera contains aloe polysaccharides which actively promote tissue and cell regeneration and are anti-inflammatory. Aloe can also form a thin mucosal coating in the lining of the GI tract that can remain for up to 48-hrs, which can provide fast relief. Find it in your local health-food shop.



  • Linseed (micronized), a staple in my feedroom as you all know 😉. Apart from all its other health benefits It’s also a gut system superstar. Thanks to its high soluble-fibre level (around 27%) this makes it high in mucilage, so wonderfully lubricating for the inflamed gut membrane. Another of the many benefits of micronization is that it beneficially changes the structure of the seed’s grain which greatly increases digestibility in the small intestine by up to 90%, helping to reduce the burden on the large intestine and reducing the risk of overloading the GI tract and hence reduce the risk of colic, laminitis and acidosis.


Herbal Therapy

There are some really beneficial herbs to feed as food for an easy and effective way to support gut health. Essentially, you’re feeding the equine gut the beneficial plant chemicals the way evolution designed it millions of years ago, the design of which to this day hasn’t changed.


  • For instance, bitter receptors throughout the GI tract are still programmed to respond to bitter flavours (found in herbs) to activate the release of saliva and enzymes to pre-digest food. Look to Andrographis, Dandelion Leaves and Sarsaparilla.


  • Certain herbs carry potent antimicrobial and detoxifying compounds that help fend off pathogens and eliminate toxins.


  • Mucilage herbs provide a demulcent - a substance that relieves irritation of the mucus membranes by forming a protective film that acts like the mucus barrier in the gut until you've rebuilt the mucosa.


  • Berberine helps promote a healthy microbiome with natural chemicals that help suppress the overgrowth of microbes in the small intestine.


  • Spirulina has potent detoxifying powers, thanks to its rich stores of the chlorophyll pigment, which binds to toxins in the GI tract and holds them there, preventing them from being absorbed. These include herbicides, pesticides and mycotoxins, as well as heavy metals and plastics such as BPA and phthalates, which are being studied as possible endocrine disruptors and carcinogens.


* C.R.A.P. - not me being rude; it stands for Carbs Refined Artificial Processed.


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