I’ve just completed an IFM (Institute of Functional Medicine) workshop on the much discussed and now very prevalent SIBO, and one of the reasons I love the FM concept is that it recognises that disease doesn’t occur in isolation.

If one part of the body is compromised, the entire body is thrown out of balance and SIBO is a great example of this – it rarely occurs on its own and is often paired with a number of other issues. When we focus on healing the gut in this instance, the entire body shifts for the better.

The term SIBO (Small Intestinal (SI) Bacteria Overload) is basically food fermenting where it shouldn’t be. Food’s meant to be fermented in the large intestine by the cellulose fibre-fermenting bacterial microbes, but the food’s landing first in the SI where there are the wrong kind of sugar-loving, pro-inflammatory bacterial bugs which ferment that sugar. This gives us an immediate two-fold effect – first up, those bad bugs start to multiply by the gazillion which creates a state of dysbiosis in the microbiome. Second, fermenting creates gas, and the SI doesn’t cope very well with gas, so now you’ve got gas where it doesn’t belong, and it’s very, very uncomfortable.

We all know by now that gut health is completely central to overall health and wellbeing. Apart from the gut housing at least 70% of the cells that make up the immune system, the gut also depicts what nutrients are absorbed and what toxins, allergens and pro-inflammatory pathogen microbes are kept out. When gut health gets out of balance it affects every other aspect of the body’s health very negatively and very quickly.

Dysbiosis is an imbalance of good bugs v. bad bugs in the microbiome, and when there's more of the bad bugs this leads to a breakdown in the gut barrier which causes leaky gut. All these foreign proteins and toxic bacterial components leak into the body, so the immune system hits Red Alert and goes into overdrive, creating an autoimmune response. This creates systemic inflammation which is why we get so many symptoms that we think aren’t connected but they are. This is why SIBO is now such a researched topic because it connects the entire body matrix.

It’s only really over the last few years that SIBO has become recognised as a major player in contributing to poor health. Back in the day, pre the 1960’s when we were all eating natural, heath-giving, unprocessed foods, and not the C.R.A.P diet (Carbs/Refined/Artificial/Processed), SIBO was barely a thing, but these days it’s everywhere and everyone’s suffering, including our horses. The SI should be a sterile, pH-neutral environment, yet bad bugs are growing in it, and they have a really bad impact on health. So, what are the SIBO symptoms and problems?

The SIBO effect in our human world

As always, there's next to zero studies on equine SIBO but there's a ton in our human world, so let’s hop for a moment into how it happens for us. Let’s look first at the SIBO symptoms – we’re talking bloating, distension, a blown-up belly that feels like it’s been pumped up by a bicycle pump. For some it’s not fully evacuating the bowel; for others it’s associated with depression/anxiety, exhaustion and brain fog; for most it’s both. Another well-recognised affected area is in the joints - muscle ache and joint inflammation. Above all, SIBO causes misery.

Science doesn’t yet know all the causes, but what is known is that PPIs/gut acid blockers significantly damage the microbiome, along with the well-known part that antibiotic drugs play. Stress also plays a major role along with toxic poisoning and environmental toxicity from our water, soil and air, and for our horses, especially when agri-crops are being sprayed.

Overall, when the microbiome is disordered and these bad bacteria are growing where they shouldn’t grow, everything changes - how food is processed and where it’s processed. SIBO impacts nutrient absorption and creates whole-body inflammation, which translates to the gut/brain connection, and this is why there’s so much overall improvement when SIBO is addressed.

You’ll rarely see SIBO by itself because it’s about the whole microbiome, the very eco system of all the trillions of bacteria bugs in the gut system. These bugs outnumber the body’s cells by 10-1; they outnumber DNA cells by 100-1, and they’re linked to everything from autoimmunity, heart disease, cancer, diabetes, obesity and dementia, to name a few.

What we also know about the microbiome is that it trains the immune system – it’s able to tell the immune system what it needs to be worried about, and what it doesn’t. So, when the gut immunity is altered it creates inflammation in the SI, which begins to break down that fragile gut wall membrane that’s responsible for letting the good compounds and nutrients into the bloodstream to fuel the body, and for keeping the bad guys out of the body.

When it breaks down, that’s leaky gut. And now the immune system starts to see proteins that haven’t been completely broken down to the peptide levels they’re accustomed to, so it starts making antibodies against commonly eaten foods.

So, we know there’s something going on down below because we’re bloated, full of gas, our No.2’s aren’t right, and oh boy our gut hurts. We also seem to be sensitive to regular foods we eat every day, so now we’re either not eating, or we’re so uncomfortable that we don’t know what to eat, because everything we eat exacerbates the symptoms and the pain, which can be crippling.

Meanwhile, those antibodies and the associated inflammation is now causing muscle ache, joint pain, brain fog, fatigue – even skin rashes and acne. Finally we’ve had enough – we’re hurting all over so off we go to our GP. And herein lies a major difference – us humans can tell our GP what’s going on, but a horse can’t.

We give our GP the whole story so, provided they look a little deeper and see the SIBO connection instead of simply suggesting pain relief or something to relieve constipation, a SIBO breath test will be ordered. This basically involves a day’s fasting to starve those SI bacteria so they become metabolically inactive; then we’re given a sugar drink so the bacteria get very excited that they’re no longer doomed to die because they’ve now got some food – even better, sugary food! So, they get very metabolically active, and after around 30-60mins they start to produce the exhaust of their metabolism – hydrogen, methane, sulphuric acids – which we then burp up. It’s not just the cows who are burping methane!

There are other tests, i.e. an amino acid depletion test and urine tests, but basically a breath test burps up the gases so the science knows what bugs are, what aren’t, and what should be, in the gut. And so SIBO can clearly be detected in us humans.

The gut:brain connection

During the workshop we heard of a historic case, a young 9yo girl, very sweet looking but an absolute monster. She was constantly kicked out of class, rarely made it home on the school bus without the driver having to stop all the time, she was violent, hated her family, tore up family photos and terrorised her sister. The family’s regular GP was out of ideas – they’d tried every conventional drug from ADHD to autism and nothing worked. Finally the family went to a FM clinic, who did a whole work up of tests and found a massive overgrowth of bacteria as well as fungal overgrowth (SIFO) in her SI. They gave her antibiotics and antifungals and she literally transformed into an angel.

So how does treating a psychiatric disorder with antibiotics and antifungal make sense? It’s that ‘everything’s connected’ mantra again because when you understand the connection between the gut and brain, it makes perfect sense 😉



SIBO’s very commonly related to neuropsychiatric disorders – people with memory loss, brain fog, ADHD, autism - with positive results often seen by fixing the SIBO and changing diet from C.R.A.P to a healthier, less contaminated one. Generally, within 6 weeks, significant changes in ADHD behaviours, and verbal abilities with autism, have been seen.

Ticks - Lyme disease

Very often there’s an underlying cause, and one coming to the fore is tick infection, which can literally paralyse the gut. Lyme disease is becoming more widespread in humans, and these days if a SIBO patient isn’t getting better, FM clinics are now testing for Lyme Disease, which for the record is also becoming more common in horses too. In humans one of the symptoms of Lyme is facial (Bells) palsy, where the facial nerve becomes paralysed, so another useful test.

A similar syndrome can happen in the gut – scientists are seeing paralysis and dysfunction in the migrating motor complex, the SI’s smooth muscle activity during periods between meals, thought to serve a housekeeping role and sweep residual undigested material through the SI. This is causing a decline in SI peristalsis so the SI and its undigested contents literally doesn’t move. In other words, the ability to successfully move the bacteria to the large intestine for elimination is seriously inhibited, so this means the bad bacteria sit tight and populate like crazy, which leads to fermentation happening in the wrong place and - you've guessed it - the development of SIBO. So again, it’s all connected.

The Stress word again

We’ve established that SIBO itself isn’t necessarily the root cause of all these symptoms but more than likely there’s something that’s causing SIBO in the lifestyle. And here’s where the Stress word pops up again. But what does stress have to do with the intestines? Aha … more ‘connection’ again 😉

As I quote on the website on our Stress page:

“An ongoing stressed state is very often the underlying reason behind the root of chronic disease. The science is conclusive; unmanaged stress is the first domino that falls, creating a chain reaction of internal complications that can lead to serious health conditions.” 
Institute of Functional Medicine

Stress impacts everything, and especially hormones as it creates neurochemical changes in the brain, and thanks to the vagus nerve – the superhighway from gut to brain - there’s a communication between the brain and the gut microbiome. Some call the microbiome the 2nd brain, although some think of it as the 1st brain, and that the human brain only developed once the mitochondria started to make enough energy for the body to make a 2nd brain which allowed us humans to ‘reason’. But that’s another story for another day 😉

However, once you have the gut:brain connection via the vagus nerve, the brain can communicate anxiety and stress to the gut microbiome and change its make-up. And let’s not forget the nervous system connection – stress hormones literally paralyse the gut – cue the sympathetic nervous system and the Fight/Flight response; you don’t want to be using energy to digest food while you’re being chased by a tiger – we want the gut to be shut down so all the energy’s going to the muscles to run fast!

To conclude

Long and short, stress creates the environment for SIBO to develop, but SIBO’s just part of the whole complex, because once you’ve effected dietary changes then you’re affecting everything from hormone function, immunity/autoimmunity function, and so on. It should ultimately start with the diet because diet impacts all the body’s systems for good or bad.