• Quality Assured
  • Quality Assured

The Hindgut Acidosis / Dysbiosis (SIBO) / Leaky Gut cascade

A Case Study. And introducing Lactic Acid - the hindgut's worst enemy

These days I get so many enquires that all end up relating to hindgut acidosis. It’s so prevalent out there that I’d almost go so far as to say it’s the root cause behind the No.1 cry for help – without question, gut-related issues are right up there at the top.

And rightly so - in Functional Medicine, the gut system is right at the top of the pile of the 7-Interconnected-Systems - meet Interconnected-System No. 1 - Assimilation (digestion, absorption, microbiome).

One enquiry in particular was all down to a lovely boy’s gut - his whole gut system was in bits, and he was badly suffering as a result, having slowly deteriorated over the previous 5-years. He had both squamous and glandular (pyloric) stomach ulcers, plus all the signs that his hindgut was acidic as well, which meant the bit in the middle (small intestine - SI) was also pretty well shot for good measure.

All the clues indicated microbiome dysbiosis, aka SIBO (Small Intestinal Bacterial Overload) which as we know inflames the very fragile SI wall membrane and breaks it open, leading to leaky gut and seriously toxic matter leaking into the bloodstream; this then triggers a cascade of autoimmune responses with body-wide pain and inflammation - no different to us humans.

Like so many of our 4-legged clients, this boy was yet another case of a whole-body-connection syndrome - there were just too many related symptoms and too many connecting factors over his timeline of ‘issues’.

5-years ago ...

... he’d had sarcoid surgery with the accompanying - and necessary - vet meds; the downside was that these would have damaged his gut microbiome and triggered internal stress on his body. And let’s not forget that sarcoids are all about a deviously clever and deeply embedded hidden virus in the body’s sub-cellular tissues, so we also had an exhausted immune system which had been working overtime trying to fight it; hence his overall recovery took much longer than expected, compounding on that internal state of stress his body was already experiencing.

2-years on ...

... and he was now girthy with belly pain, and he felt slow/unbalanced, a classic sign of impaired digestion meaning poor nutrient absorption causing fatigued body chemistry, again deep down at sub-cellular mitochondrial level. No surprise as his SI's ability to assimilate all the nutrients (carbs/proteins/fats/minerals) was now disrupted, as was his hindgut fibre digestion - and lest we forget, the hindgut fibre fermentation process is the horse's main energy source.

Within 2-years of his sarcoid surgery, the original damage to his microbiome from his surgery meds were triggering everything thereafter, because the microbiome is literally the body’s CPU. I'm not disputing that antibiotics weren't absolutely necessary following his surgery, but recent studies are now showing that no organism, whether human or horse, fully recovers their gut function after a course of antibiotics.

Back to the timeline and from hereon this boy’s internal engine started to degrade. His poor gut function worsened, and it wasn't long before he was presenting externally with stress, so now his nervous system was involved. His fight/flight system was now triggered which had released the survival hormones, cortisol and adrenalin, stepping in like the autopilot to take control of the cockpit. And when this happens, cortisol's role - as the stress-managing hormone - is responsible for shutting down energy-sapping body functions in order to get all the blood supply to the where it's needed to stay alive - usually the muscles so they can run fast from a perceived threat. And ... one of those energy-sapping functions is ... digestion. I mean, who needs digestion when you’re running from a tiger?! And when you shut down digestion, well … nuff said. And another of cortisol's role in fight/flight mode? Flooding the body with acid so when the tiger takes a bite, we don't taste so good.

Pulling this altogether, the gut function was now well and truly in trouble, as was the body as a whole, because every part of the body depends on a healthy gut function because it’s the life force of the body.

Early 2020 ...

... his sheath was now permanently swollen, and it definitely wasn’t a bean 😉 Two vets later and they were close – one said ‘fatty tissue’, another said ‘muscoskeletal due to … muscle pain’. But neither explained the all-important ‘Why’ (probably didn't know the 'Why') and neither could provide a solution. It was the osteo who suggested 'ulcers', and here was more of that whole-body connection because what causes glandular/pyloric ulcers? Our old nemesis - stress.

Here’s the 'How'. The stomach/foregut’s stress-related ulcers are located in the back of the stomach by the pyloric sphincter, the opening from the stomach to the small intestine, where in the perfect world this area is well protected from the stomach acid by a lovely thick layer of protective gel-like mucus. But - when there’s a permanently switched-on fight/flight response because of stress, the gastric mucus membrane becomes much less well-supplied with blood than usual, and if the gastric mucosa is poorly supplied with blood continually, it stops producing enough of that vital, protective mucus layer.

This means the stomach acid can then infiltrate what's left of the now thinner protective layer and damage the gastric wall membrane, causing red-hot inflammation alongside a heap of red-raw pain, which in turn causes even less protective mucus! So, this self-compounding vicious circle intensifies everything and creates even more stress.

So back to our boy, and what did the vet do? For those of you who know me, you'll know this subject turns me into seething, angry middle-aged menopausal She-Devil-Woman – yep, we're talking PPIs. The vet prescribed an acid-blocking drug (one of the 'zoles'), aka a PPI (proton pump inhibitor) to switch off the acid. Gahhhhh!!! Frustrates the 'heck' out of me that these bluddy PPIs are the vets’ go-to for ulcers as they’re So Fricking Gut Damaging, but there we go … I could go into the reasons here as to why they’re so bad but it would make this page 12-ft longer than it’s going to be already. Suffice to say it’s all covered on the Ulcers' page in this section if you want to really depress yourself with what really happens when horses are fed this gut-wrecking pharma drug.

And, of course, as a result, this poor chap got significantly worse because PPIs are 100% absolutely bluddy horribly detrimental to a horse’s gut system (note how I'm being really polite here and not letting my potty mouth go off on one).

I’ll now slightly digress and chip in that boy was also a bit lame, so he also had 4 steroid injections, all around the same time; no surprise, he got even worse. His gut system was already in meltdown, his microbiome was shot and his immune system barely existed; his liver was already working overtime at having to biotransform (metabolise) all his body's toxicity, and understandably was ready to throw in the towel - frankly I’m surprised he didn’t go into toxic shock; believe me, I’ve had many clients who have. We had glandular (pyloric) ulcers and now also squamous ulcers, located at the front end of the stomach – this poor boy’s whole gut system was on the final slippery slope to meltdown.

You’ll probably not be surprised to hear that by now this chap was also clearly showing his discomfort – his ‘girthy’ had now progressed to biting, ears back at everything, lots of swinging back glaring at his right side and cow-kicking underneath his belly for good measure. So now we can bring the hindgut back into the conversation because the hindgut – the large intestine - sits definitively on the right side of the horse’s barrel so this is where all the pain is. And when there's pain in the hindgut, it means there's hindgut acidosis.

Hindgut acidosis

You see a horse swinging his head down his right side to his flanks, usually ears back and nipping at himself? Hindgut acidosis. You see a horse cow-kicking under his belly on the right side? Hindgut acidosis. A horse biting you, and not in a friendly way like a love nibble? Hindgut acidosis. And I speak from experience – our MacAttack, so named because when I first met him his only job in the world was to bite me hard and mean it - had long-term hindgut acidosis. I didn’t know this when I adopted him 5-years ago, but he came to me with a buffet of major issues so no surprise that they all manifested themselves in many ways while we cleaned him up.

When we finally fitted the last piece in the MacAttack jigsaw, we knew we’d got it right because he literally stopped biting overnight. Now when he stalks me in the field it’s to say Hi and have a face rub; now I can grab rug straps under his belly without risking losing an arm - or at the very least an arterial bleed - from his previously well-aimed cow-kick.

Put simply, hindgut acidosis sucks because it burns so it hurts – and not just for the horse but the human who happens to be nearby 😉

Meanwhile, back to our client's horse ...

Forward to Spring 2021 ...

... and this poor chap then tipped himself over the edge - he broke through a fence to a grass strip and binged his socks off. Cue faecal water/diarrhoea.

Lactic-Acid bacteria

And now we're going to introduce lactic-acid (LA) bacteria into the whole sorry scenario, because lactic-acid (LA) is the hindgut's worst enemy, and at the root of all things hindgut acidosis.

The one thing we need to avoid is the risk of LA bacteria arriving in the hindgut, but it'll get there if the front end of the gut system, the stomach/foregut, is out of whack with ulcers/pain/inflammation, and especially if PPIs have been prescribed because they shut the stomach acid production to Off.

These LA bacteria come in naturally from the forage a horse eats - especially if they're fed haylage (because for grass to ferment into haylage it need ... LA bacteria) - but the stomach acid usually deals with them before they pass into the small intestine. However, if we've got a disrupted gut system, and especially if a PPI has been prescribed, the acid wont kill them, so they sneak on through into the small intestine and Boom! One major enemy of the intestines has now invaded, and trust me when I say it'll wreak havoc.

Welcome to the lactic-acid effect. These LA bacteria ferment sugar, and if there's one place where fermentation isn't meant to happen, it's the small intestine. Belly bloat? Fermentation. So with all that sugar from a grass binge they've gone to heaven and back! Multiplying like crazy, they overpower and kill off the friendly digesting microbes - cue dysbiosis.

Next, the waste product from these LA bacteria gorging on all that sugar is lactic acid, which is badbadnotgood, and definitely shouldn’t be in either the small or large intestine becausefirstly, it lowers the pH value to sour – remember, the intestinal environment should be a sterile, pH-neutral one. Also, remember, fermenting shouldn't happen in the small intestine - only enzymatic digestion - because fermenting creates gas, and the SI doesn’t cope very well with gas as it’s a very thin tube with no room for excess gas, so it feels like it's being blown up like a balloon. So, we now have an ever-expanding gas bloat where it doesn’t belong, and it’s very, very uncomfortable.

Meanwhile, the sour LA environment inflames and splits open the fragile intestinal wall, aka leaky gut, and here we go - a runaway immune system trying desperately to fan the flames, creating a buffet of autoimmune syndromes, and the entire body feeling like it's on fire.

So, Let’s uncover some facts about lactic acid.

Introducing Pectins

One of the main culprits that causes lactic acid in the hindgut is pectins, which are a plant's cellular building material, a naturally occurring structural carbohydrate, aka 'starch'. And where do we find a huge concentration of pectins? Our neon-green leafy grass ...

Those leaf blades are full of pectins, because the leaf blade is a critical part of the grass's growth phase, to grow into a mature stemmy grass and seed head - spring grass is very rich in pectin because it's literally the new young leaves of new, growing grass. Thing is, those young growing blades have zero cellulose fibre - cellulose fibre is only found in the mature grass stems, i.e. hay or tall, fibrous, standing hay, hence why hay is the best forage we can give our horses. Hence also the main reason why our neon-green grass is not so great for our horses' hindguts.

Small amounts of pectin are always present in a horse's diet because plants use it as a building material for leaves, flowers and similarly soft-elastic parts of plants. However, pectins are primarily consumed by gut microbes that prefer an acidic intestinal environment, i.e. lactic-acid bacteria, and if the diet is overly high in pectins, they produce high levels of acid waste (lactic acid). And this is where it all starts to go wrong - an acidic pH value in the large intestine should be avoided at all costs, since the important cellulose-degrading microbes absolutely need a neutral pH environment. If it becomes too acidic, these important intestinal symbionts die off, which in the long term not only means that the horse can no longer utilise its hay properly, but also triggers the risk of laminitis, colic or cryptopyrroluria (KPU).

See our separate Pectins page for the full story.

So, back to our client's boy who was in so much trouble after his grass binge, all due to that overload of grass pectin hitting his hindgut and creating a whole bunch of pH-lowering, lactic-acid by the unfriendly lactic-acid bacteria, turning his hindgut environment into a red raw sour burn. Oh, and yes - apples and carrots contain pectins too ☹

NB - It's easy to be confused into thinking pectins are good for the gut because this is actually the case for the human gut - however, we have a very different microbiome family than the horse. If we don’t have enough pectins in our daily ration, our own gut bacteria start attacking our gut wall, so the saying "an apple a day keeps the doctor away" is bang-on for us humans, because apple pectins feed the human microbiome and prevent leaky gut.

Why? Because us humans naturally have lacto bacteria in our gut microbiome. Look at any human probiotic product label and you'll see a host of lactobacillus on the list, including lactobacillus acidophilus - in humans they're meant to be there. But absolutely not in horses ...

Another major pectin-offender is beet - sorry to all the beet lovers but it's true, and I speak from experience as I used to feed beet years ago until I learned the facts. Previously thought of as a beneficial fibre feed, beet is actually anything but. Like grass and apple pectin (often found in many horse feeds/gut supplements), beet is full of fructose (25%) and pectin-rich. The alleged 'molasses-free' equivalent may be lower in sugar but still contains up to 7% residual sugar in the pulp, and is still pectin-rich. And also promoted as safe for laminitics ...

The digestion of all starches and those grass sugars (along with proteins/fats) is all meant to be dealt with in the SI, but if the digestive function/microbiome of the small intestine is out of kilter, starch and sugar will reach the hindgut, meet lactic acid bacteria and get fermented into lactic acid. This also leads to ...

Colic risk

The general transition time of food digestion in the small intestine is relatively short, so if the SI function has been disrupted with SIBO, there will be large undigested starch and protein particles due to the short digestion time to digest those larger molecules. Hence they end up in the large intestine, which can lead to colic. So, it’s always good to be mindful of starch levels in feed when a horse’s gut function is compromised - the more complex the starch is, the more chance it’ll end up in the hindgut, and we really, really want to avoid this.


Now to haylage – probably the worst forage we can give to our horses, as the very fermentation process to convert grass to haylage needs … LA bacteria!

Just the same as it happens in the gut, the fermentation process lowers the pH so makes it more acidic – my connie, Murf’s, gut literally turns into a projectile, high-pressure faecal water spray within just a few hours of eating haylage. There’s a separate page on the website giving the full gory details of why haylage should be avoided at all costs – it’s literally lethal for our horses.

Remember that swollen sheath, with one vet saying ‘fatty tissue’, and the other saying ‘muscoskeletal due to … muscle pain’. Again, a connecting factor to LA, so the vets were close, but didn’t quite make the connection.

LA can cause the skelelal soft-tissue, i.e. ligaments, tendons and muscles, to feel as if they’re ‘on fire.’ Why? Because when we have dysbiosis/SIBO causing leaky gut, the LA leaks through the permeable gut membrane (leaky gut) into the bloodstream.

The body's natural liver/kidney detox function doesn't know what to do with all these toxins so they're sent back into the bloodstream to be stored in the connective soft tissue - yes we're talking tendons/ligaments/muscles - where they create their own acidic inflammation and damage the sub-cellular structure. Some vets think it’s ‘fatty tissue’ because the inflammation can look as if the horse is putting on weight, but it’s actually the lymphatic system sending its fluid – lymph – to the inflammation to urgently try to degrade the LA.

Another factor is the horse’s history - we rarely know what’s gone before with our horse unless we bred them. When a foal is born they don't have an established microbiome - their tiny gut system is beautifully sterile, so the gut microbes need to get to the hindgut – a foal does this by a process known as coprophagia, which is eating their mother's faeces.

The first 4-5 months is crucial for the foal – by eating mum's faeces the foal naturally colonises its hindgut's fibre-fermenting microbes (that reside in the cecum) just as the rest of their intestinal flora forms a stable microbiome. Disturb this process or wean too early, and the foal will end up with lifelong digestive and metabolic problems. If you give a foal antibiotics, or feed it haylage, this will disturb the process of the microbes learning to live in the young gut. See our Creating the foal's microbiome page.

It also completely depends on how the mother was raised from a foal, and how she's been fed/how healthy her microbiome is, i.e. if she was fed haylage or antibiotics at any time. If so, and therefore by default, if the mother has lactic-acid bacteria in her hindgut, the foal’s immune system will acknowledge the lactic-acid bacteria from its mother’s faeces as ‘normal’, making lactic-acid bacteria a lifelong resident. In other words, if the mother has the wrong microbes, this will be passed on through the generations.

This will dramatically affect a horse's future ability to ferment the cellulose fibre in the hindgut, which will have the direct effect of dramatically affecting the horse’s energy. In these cases, it’s essential to change the feed regime to 24/7 hay which will create a hostile environment for the invader microbes by starving them of their beloved sugar; this will then allow the beneficial microbes to recolonise and outgrow the bad bugs.

This is sadly so widespread these days as so many breeders are feeding haylage to their foals - already we’re seeing foals with metabolic problems, i.e. sweet itch at age 2. Totally a human made problem.

Pulling this together

Basically, feed a horse wrong and it creates the wrong microbes which are passed on through the generations. For the last 20-30 years, most scientific research has been focused just on the small intestine, yet the crucial fibre-digesting takes place in the hindgut. Scientists are now realising they’ve strongly neglected the hindgut but are now realising that a healthy hindgut = a healthy metabolism.

The last decade has been the decade of human microbiome research, discovering the connection to so many human-related gut conditions, i.e. IBS, Crones, Celiac, gluten intolerance and so on., so research has intensified and interest has grown – it’s now known that the microbiome manipulates everything!

The good news is that as a result, there’s now more research happening on the equine microbiome with the first publications now coming out, and the early realisation that so many horses have disrupted microbiomes at the root cause of many metabolic disturbances, especially in the IR lami-prone horse resulting in colic, faecal water syndromes, trapped gas – all signs of dysbiosis in hindgut.

A disturbed hindgut intestinal biome is also now thought to be behind the relatively unknown, yet now widespread, multi-metabolic detoxification disorder, Cryptopyrroluria, aka KPU, which is very much connected to many autoimmune syndromes such as sweet itch/pollen allergies/mallenders, plus so many more syndromes, which the latest research now shows also have their root in a disturbed microbiome. This ultimately, for so many horses, could well have started with not giving the foal the chance to colonise its cecum microbes appropriately.

See our KPU page for the full story, and to see if it resonates with what's going on with your horse.

To conclude

So, there we have it - enough of the ramble, and let’s pull this all together. Back to our client's boy and a week ago this poor boy's entire gut system was in meltdown, his whole body felt like it was on fire, and his sheath and inside legs were swollen from lactic-acid storage in his soft-tissue cells.

So, what to do? No question - our Alleviate, Detox and Fortify protocol. For this chap we needed to reset him back to his natural state by first stabilising his pain and stress, then he needed to get off the ultra-processed feedbags by switching up his diet/forage management to species-appropriate, aka grass forage, and getting him off the neon-green and onto hay.

Once stabilised, it was then all about cleaning him up from the inside/out with a full body detox (although for other horses who may have had a detox in the previous year it's worth considering a 1-month course of our SIBO-CARE), alongside our GutAminos to start repairing the leaky gut damage to the intestinal membrane. Thereafter it's a 1-month/1kg course of our BiomeTonic alongside our WildFed mix to add valuable nutrient diversity to the diet.

Our client is completely onboard - she's already got the protocol underway, and removed the offending feedbags from his feedbowl. As for grazing on grass? I think you know the answer to that! He’s been switched to hay, more hay, and nothing but hay, 24/7, 365-days/year 😉

Here’s wishing this lovely chap a happier, stress-free, and certainly a more comfy and pain-free future.