4th April 2018

I have written about Small Intestinal Bacterial Overgrowth (SIBO) – a LOT…

Within my most recent post I wrote about the diagnostic standards of SIBO – and referenced the correlation between testing aspirate from the small intestine and using breath testing methods. However, I began this article with a nod to the fact that between the time of my writing and the time of posting – this article by Dr Christianson came out, entitled, “Is SIBO a Real Condition?”

He, of course, concluded that it wasn’t. He made several points – much of which I actually have covered in my lengthy discussions about SIBO – I’ve covered the diets for SIBO here, I’ve talked about the myths of SIBO recurrence here (even mentioning that SIBO is the new candida – over-diagnosed, overhyped and the latest catch-all diagnosis), I’ve discussed the mental and emotional sides of SIBO here and I even did a really deep dive into the science (yup, that’s right, actual science) of SIBO here.

As you will ascertain if you read any of my articles – there is a lot of nonsense bandied about regarding SIBO – there’s a lot of unqualified people discussing it like it’s a permanent curse, but there are also a lot of rational and moderate practitioners who carefully assess SIBO in the context of their patients’ cases and incorporate treatment of it as and when necessary.

To be charitable, I will say that Dr Christianson may simply be picking up on the groundswell of noise about SIBO from those who aren’t as clued into the science as many of the professionals working in this area might be. It is the diagnosis everyone is getting now and the myth and misinformation is being perpetuated by nutri-bloggers who are on a ‘SIBO diet’ (which doesn’t quite exist… as I wrote about here) and lamenting “my SIBO” as if it’s the latest fashion.

So, it is true that I see A LOT of SIBO – many of my clients have it. But then, my sample set is highly specific because I advertise as specialising in gut conditions and SIBO. The same is true for many gut-centric health professionals. Regrettably, this means it looks really common and this has led to a slew of “could your symptoms be SIBO?” articles.

The problem with the internet is that unless you insist on writing really long blog articles like mine (and choose not to care that practically nobody reads to the end of them) then the shorter versions that attract attention will be clickbait-y and seriously lack nuance, caveats and the necessary moderation necessary when discussing the finer points of digestive health.


In the arena of articles and blog posts which lack depth or nuance but promote SIBO as the root for most gut conditions, Dr Christianson’s article makes a lot of sense. Not everything is SIBO, many conditions have SIBO as a component but the SIBO is far from causative… and SIBO is not simple, nor is it just one thing – and nor is it validated scientifically in the way many practitioners claim. It is no wonder, given the inaccuracies perpetuated, the Dr Christianson saw fit to write his post.


And yet, the more moderate voices among us are already exceedingly cautious about SIBO. We aren’t gung-ho about diagnosis – and we ADMIT all of the above. We talk openly about the vagaries of SIBO testing and the necessity for accurate and intelligent test analysis which takes into account case history and symptom pattern, not just treating based on data and numbers.

Many in the Functional Medicine community would agree with Dr Christianson’s sentiment – there are a lot of myths around SIBO that are nonsense, such as:

  1. All gut issues are SIBO
  2. SIBO is really difficult to treat
  3. SIBO requires antibiotics to treat
  4. SIBO antibiotics are dangerous
  5. SIBO can be treated by diet


As you can see from the links to my own blog – I have written about (and worked to dispel) ALL of these myths before. And yet, I have done so within the context of STILL validating the fact that SIBO is real. This is a very different take from Dr Christianson’s dismissive view that SIBO is nonsense.


So let’s take Dr Christianson’s points one by one and work out where and why his conclusions diverge from mine, despite us both, pretty much equally, dis-believing the SIBO hype.


1) There is no Best Diet for SIBO


YES! There isn’t – I’ve written about this here. But I don’t conclude as Dr Christianson does – that this is because SIBO is a “failed hypothesis”. Using the term ‘failed hypothesis’ is fancy and scientific, but it carries little meaning in this context. It is used to dissuade the reader that there is evidence for this condition – but stating that SIBO is a failed hypothesis is not the same as proving that SIBO is a failed hypothesis. The proof is supposedly presented by the remainder of the article, but as you will see Christianson rather fails to prove his ‘failed hypothesis’ theory.

That said, he IS right – there is no ‘one perfect diet’ for SIBO because there is no perfect diet for each person – everyone is individual, and the way we interact with and respond to the bacteria that we host is as individual as we are. SIBO is merely a term which describes the presence of excesses of bacteria within the small intestine. Nowhere is it specified which bacteria, how many or where they are located precisely – just that they are creating symptoms.

This means that because small intestinal bacteria can be as numerous and as diverse as that of the large intestine, each person’s SIBO will respond differently to different food groups/types/fibres. This is why finding YOUR SIBO diet is part-logic (that’s my job) and part experimentation (that’s the patient’s job).

And nowhere do those who are even vaguely knowledgeable about SIBO suggest that the diet is curative. We just don’t. Diet helps with symptoms… resolving the issue requires an understanding of the cause – and this is almost never diet-related.

So just because there’s no ‘one diet’, this doesn’t actually invalidate the fact that diet changes SIBO symptoms… and that SIBO itself exists. Not having a miracle diet to cure any condition doesn’t mean that that condition isn’t a real illness.


2) As bacterial concentrations in the gut are the determinant of whether someone has SIBO – “If these bacteria cause symptoms, there should be a relationship between how many bacteria are in the small intestine and how severe are the person’s symptoms.”


Again, here we have a conflict – because there is nothing to say, in any medical condition, that with the same test results two people’s experiences are the same. Ever. This goes for blood tests, nutrient levels, liver, kidney, thyroid function tests… every test we have has to have a cut off somewhere, and most of the time these cut-off points are fairly arbitrary. This isn’t about a line where on one side of it you’re fine and the other you have symptoms. Everything within a diagnostic test scenario is a continuum – and different people experience different severities of symptoms at different points along that continuum. This goes for whatever condition the patient suffers from.

This, in a way, is the whole reason why Functional Medicine exists. Referred to as systems-biology medicine, those who work within it comprehend that isolated testing is largely irrelevant to the whole case. Two identical gas levels for SIBO can be experienced differently depending on SO MANY other factors – not least of which is the nervous system sensitivity of the gut, which varies hugely from person to person. But on top of this there’s motility, permeability, acid/enzyme/bile levels, constipation levels, nutrient deficiencies, liver function and detoxification ability – and thyroid health, food sensitivities, immune wellbeing…

Your experience of any condition will vary depending on what else is going on in your body (and, to be honest, in your life). Therefore it is never going to be the case (with any condition) that symptoms are based solely on the analysis of one health marker (in this instance, bacterial quantity).

Therefore, this point is again invalid – diagnosis of any illness doesn’t require consistency that is measurable in such isolation.


3) SIBO tests aren’t checking SIBO at all – they’re looking at transit time


The weird thing about this point is that Dr Christianson neatly avoids the truth – he is 100% right that these tests can be used to test transit time. But they are useful in that regard PRECISELY because of the way bacteria ferment the solution and give off hydrogen gases – wherever those bacteria are.

These tests certainly BEGAN as a way to test transit time – and then it was discovered that those who were most symptomatic of certain conditions also had fermentation much sooner in the testing time than anticipated. Contrary to this being due to fast transit (tested and proved false by using actual motility marker studies) it was established that this early fermentation wasn’t because the solution had moved rapidly through to the colon – it was because there were bacteria higher in the gut – hence the SIBO diagnosis was born.

It’s not enough to say that these tests aren’t testing for SIBO. It’s kind of true, it’s just irrelevant. A blood test isn’t testing for heart disease … it’s testing for the markers that suggest that heart disease is occurring. So too with SIBO – the tests check for bacteria… wherever they are and however much they’re fermenting.

And yes, if I am AT ALL concerned that a SIBO test may be inaccurate due to fast transit time… I have my clients do a very unsexy but utterly useful at-home transit test. Eat beetroot or sweetcorn and judge how quickly this comes out in your stool. If it’s within hours, you may have fast transit and this will change test interpretation.


4) Most patients with IBS have low small intestinal bacterial levels so SIBO doesn’t exist and it’s really just IBS, which is not correlated with small intestinal bacterial levels anyway


Again, Dr Christianson makes lots of assumptions without spelling them out here. He’s making the assumption that IBS is linked to SIBO (which is suggested by the literature, though the figures are far from agreed upon). He is also assuming that IBS, SIBO and small intestinal bacterial levels should always correlate or be linked and measurable linearly (more bacteria, worse symptoms and this is tied directly to IBS). This is an irrelevant fantasy. No one person’s IBS is ever someone else’s – what causes it isn’t the same and the bacteria can have a lot, or very little, to do with it. Nobody has ever suggested that all IBS is SIBO – and, as per my first point, the gut of each person is as individual as they are.

But moreover, even if we accept his assumption that SIBO has to be linked to IBS, if you read the full paper that he himself cites, the researchers themselves conclude that, “The present case–control study showed an epidemiological association between irritable bowel syndrome and small intestinal bacterial overgrowth.”

I’m sorry… what? Yup – this is yet another situation where a blogger cites a study which directly contradicts their own statement… Not only that, but Dr Christianson refers here to a study of “126 people with IBS symptoms… (doing) hydrogen breath tests on 80 of them” … but he then links to this study – which used 102 healthy controls and 65 IBS patients… So, in his points he is clearly discussing the details of a different study but then chooses not to cite it and to cite this one instead… which doesn’t even prove his point.

Now, I’ll admit – this is just confusing. I have NO idea how anyone who wants to simply trust an online doctor is supposed to have ANY chance of differentiating fact from fiction – particularly when we just see references and assume credibility AND that the references qualify the points made within the article. But this is not the first, and it won’t be the last, time that a blog post uses fancy numbered references and yet those studies bear no relationship to the points in question – often directly contradicting them.

The other point of note about the test in the study which Christianson linked to is that even though it found correlations between SIBO and IBS it used a glucose solution. The perils of using glucose to test for SIBO are what I discussed last week… and mostly, this solution is absorbed prior to reaching the large intestine (when a person’s transit time is good). When transit is too fast it can give higher readings, sooner – and this is why glucose testing can be used to assess transit time. This unwanted transit testing issue is precisely why we now use lactulose to test for SIBO, not glucose.


4) Breath tests aren’t accurate and change


The ENTIRETY of the stupidity of this point is covered in the comments above. The whole essence of the digestive system is that it is an evolving ecosystem. A night of missed sleep will change your microbiome – no diet or treatment required. Consistency of test results aren’t necessary, nor are they expected. I would challenge Dr Christianson to test some blood markers – blood markers which we DEPEND upon for prescriptions (for cholesterol and statins for example) and monitor them over time. They will (and do) fluctuate and change – dependent on exercise, sleep, lifestyle factors, diet, stressors. They can fluctuate quickly and unpredictably. This is why doctors (and all health professionals) should examine trends correlated with symptoms and case history to establish the reality of every diagnosis.

We don’t ever JUST use a test to suggest bacterial overgrowth – we tie this to symptoms, case history and progression of illness (including an assessment of risk factors) before diagnosing anything.


5) Antibiotics don’t work…


Here is where I start to get REALLY mad… because again we have references to studies which bear no relation to the points made.

Dr Christianson’s resource 12 is this study here which actually concludes:

Significantly more patients in the rifaximin group than in the placebo group had adequate relief of global IBS symptoms during the first 4 weeks after treatment… Similarly, more patients in the rifaximin group than in the placebo group had adequate relief of bloating… In addition, significantly more patients in the rifaximin group had a response to treatment as assessed by daily ratings of IBS symptoms, bloating, abdominal pain, and stool consistency. The incidence of adverse events was similar in the two groups… Among patients who had IBS without constipation, treatment with rifaximin for 2 weeks provided significant relief of IBS symptoms, bloating, abdominal pain, and loose or watery stools.”

And yet, Dr Christianson uses this study as evidence that “once you factor in placebo response, for every single person who improved from taking Rifaximin, ten did not get better”.

The truth lies well in between these two extremes…

What the researchers mean by ‘significant’ is statistically significant. This is a complex stats calculation based on ‘p’ values. And they’re right – Rifaximin is statistically significantly more effective than placebo. However, that doesn’t mean a hell of a lot and can often equate to just a handful of patients.

And yet it doesn’t equate to patients doing WORSE on Rifaximin, or Rifaximin being NO BETTER than Placebo – which is the inference you are left with from Dr Christianson’s claims. For more about the “Placebo vs.” Effect – see the section with this title below.


Dr Christianson goes onto reference some psychological therapies etc. as being beneficial for SIBO… which no-one is denying… and yet just because psychological therapy helps a condition, it does not mean the condition is all a fiction of the patient’s imagination – or an imaginary condition that doesn’t even exist.

Sometimes it baffles me how people don’t understand this distinction: just because a human brain can drastically help to improve a situation, this does not IN ANY WAY mean that either the human brain caused the situation and/or the situation was a figment of the imagination of said human brain.


It certainly doesn’t challenge a diagnosis because placebo helps as much as drugs. If this were the case, entire diagnostic manuals would be re-written and the pharmaceutical industry would go out of business.


6) Carbs don’t cause SIBO…


Oh FFS – nobody says they do. We just know that fermentable fibres (like those found in carbs) are fuel for bacteria… and they can feed off them more easily than they can off fats, bile acids and short chain fatty acids. Sometimes, we even prescribe Elemental diets (no food, just amino acids and starches for calories which are all digested in the stomach) precisely because WE KNOW that bacteria don’t just feed on carbs and we need to limit all food supply to the small intestine.


7) Diets don’t work… at least not better than hypnotherapy…


As I’ve said so often, there is no ‘one’ SIBO diet, and more importantly, food is just one part of the complex SIBO puzzle. If you are looking for a miracle dietary fix for something (whatever the condition) then this really is no better an approach than the conventional ‘pill for an ill’ – it’s just that the pill you’re using is a dietary strategy rather than a medication. So, there should be no expectation that for a condition to be real it needs to have a dietary solution.

Dr Christianson goes on to quote Koch’s Postulates. This is a set of criteria which determine a causal relationship between a microbe and a disease. Christianson is correct in that SIBO does not fit the criteria for there being a causal relationship between a single microbe and a disease. But then, no-one claims that SIBO is the result of just one microbe, nor that it is a ‘disease’ state, in the classic sense of the word.

This is where terminology and language become fundamental. When discussing the gut ecosystem, parasites or worms would fit Koch’s Postulates – in that a specific bacteria has been proven to be linked to a specific disease under all of the criteria set out within Koch’s rules (the bacterium is present in every disease case, isolatable from the host and can be grown in pure culture (this one’s tricky with some anaerobes), when implanted within a healthy host the bacterium will cause the same effects, the bacterium is recoverable from said healthy subject).

However, when discussing guts and dysbiosis we are talking about populations of bacteria and ratios of these populations – not absolutes or single microbes. As such, we deal more frequently with ‘pathogens’ (which can be healthy bacteria in the wrong concentrations or locations) rather than strict disease-causing bacteria or microbes. We are dealing with populations that at certain levels are healthy and left to grow wild are utterly destructive. Think of the gut like a community – within the right ratio the behaviour of the anarchists can be kept in check. Left to overpopulate the environment they can wreak havoc.

This grey area – where illness is determined by quantity, comparative ratios and the remainder of the ecosystem, rather than absolutes – is clearly a tough one for Dr Christianson to contemplate or make peace with.


I understand Christianson’s conviction that SIBO doesn’t fit a diagnostic criteria for infectious diseases … but I do not share his view that this makes it not a state of dis-ease within the human body. Granted, SIBO is possibly overly focussed on right now, may be over-diagnosed and certainly not the root cause of all bloating, as some would have you believe. But nor is it the sham diagnosis that you are left to believe it is by his article… and the “IBS Subtype” diagnoses that he is promising are the real reason for your digestive symptoms… hmm… these are all flimsy distinctions which describe stool pattern and give even LESS insight into causal factors than the SIBO tests… Why he wants to rubbish an actual condition in favour of murkier diagnostic criteria for vague subtypes of the catch-all diagnosis of IBS is pretty much beyond me.




I care, deeply, about articles like this for several reasons.

Firstly, they discredit the work of the scientists working in this field attempting to understand the grey area of human biology, rather than simply dismiss grey areas as too fluid for exploration.

Secondly, these type of articles, which aim to dispel SIBO myths, mis-cite evidence from research and, in so doing, create further SIBO-based myths.


This does nothing for the mindset of patients and this deeply worries me because SIBO (and, to be honest, most gastrointestinal issues which are functional in nature) have a huge psychological component to them. It’s just the way of things – the gut-brain connection is so powerful.

I am one of the first to acknowledge that handing someone a diagnosis and a prescription (SIBO… and Rifaximin, for example) is a powerful PSYCHOLOGICAL tool, as much as it’s a physical one. The same is true for any dietary iteration or elimination. These things are powerful empowerment tools. Diagnosis, explanation and supplementation is a lifeline as much as it is a treatment. And alongside the biochemical treatment itself, it offers hope and solutions. For those in whom eating and digestion has become traumatic, the impact of this cannot be denied.


A Final Word on Gut-Brain Connection: Placebo Vs. …


When it comes to gut health – in fact medical care at all – we often find the Placebo effect being bandied about as if it’s a bad thing, or negates the impact of something. So much of Dr Christianson’s SIBO dismissal is based on the fact that the placebo effect can influence the outcomes: the accusation being that if our brains play a role in something then it can’t be as serious, or perhaps as real?

In truth, the placebo effect doesn’t invalidate anything. It is just so powerful that every research study has to control for it. That’s the whole, entire point of randomising and double-blinding… we are controlling for placebo and the influence (the almighty and powerful influence) of the human mind.

In such a situation, Christianson seems to be using placebo as a dirty word, or as an endorsement of his questioning of “how can SIBO exist when placebo can treat it”. However, someone like me takes an ENTIRELY different view. It’s possibly a different WORLD-view.

Part of my ‘bag of tricks’ as a practitioner is the mental attitude and the mindset. Belief – both what you believe about your own condition and the tools used to treat it – is fundamentally important. To suggest that a condition is non-existent because mental power can help to overcome it is to fatally misunderstand gut conditions and health in general.

Within the gastrointestinal tract you don’t just have the structures or organs, the bacteria, the enzymes and other digestive agents and the food that you eat. You don’t just have all of this plus immune activity, gases, endotoxin and a whole host of other compounds. What you also have is an entire structure that runs almost the whole length of the human body, is entirely in contact with BOTH the outside and the inside worlds at the same time – it’s a complex thing. On top of that, this whole structure is controlled, regulated, innervated, tensed, relaxed, moved and influenced by the nervous system.

At the very top of the nervous system is the brain itself. So it stands to reason that when you are dealing with a gut condition, the brain itself is implicated in the symptom interpretation, response and resolution. Sometimes, it is even implicated in the symptom creation. Because our bodies are elaborate feedback systems we cannot divorce ourselves from our brains. And this is one of the main reasons why everyone’s experience of their gut conditions is utterly different. Because it is interpreted through and mediated on the nervous system relay of messages. And this relay works in reverse.


Placebo’s power in gut health is established, evidenced – and, for those of us who work within this field, very often leveraged for its potential to help with the healing.


This means that when I understand how impactful placebo can be for a condition I simply respect the role of the brain in the healing progression of the body. I don’t automatically disregard the condition with the false impression that it ‘can’t have been real, then’.

And I think, above all else, this is why I really care about Dr Christianson’s article. It calls into question the personal experience of countless patients. Realistically the labels don’t much matter when it comes to gut stuff – it’s why doctors have got away with the rather lazy ‘Irritable Bowel Syndrome’ diagnosis for so long. So SIBO, IBS, dysbiosis etc. etc. – the label matters only insofar as it gives us explanations and understanding.

Having a new label of SIBO might seem like we’re pathologising something unnecessarily which was adequately covered by “IBS”, but this doesn’t change the fact that bacterial fermentation within the gut can cause distressing gastric symptoms – and treating those bacteria in a way that lowers their concentration relieves that gastric distress. Knowing where that bacteria is (upper/lower gut) can direct treatment and distinguish one person’s experience from another’s.

Discrediting a diagnosis based on Dr Christianson’s views as explained above is disempowering and short-sighted. Whilst the world of gut health has a lot of improvement to make, suggesting that something is nonsense based on flawed definitions of what constitutes disease and treatment success is just another way to a) get a clickbait article which creates a buzz but also fuels panic and fear among patients and b) get people like me to further fuel traffic by having to write a rebuttal to the article. It’s also a way to confuse patients. Dismissing someone’s reality is not actually fair, and it’s certainly not kind.

I hope that Dr Christianson actually reads the content of some of the people who work within this area to understand that just because there are precious few black and white, hard lines in gut health – this doesn’t invalidate diagnostics or render the condition itself a nonsense. Sure, it may mean that it warrants more science/data/investigation… but every condition we now know to be a ‘thing’ started off as a poorly tested, improperly understood hypothesis. Science and self-understanding has to start somewhere – and articles like his do nothing for the cause of furthering the understanding of human health.