Have you heard all the talk about getting your poop tested? Me too.
There’s loads of hype about them, because they say it’ll tell you what’s causing your symptoms and how to correct it. And, because we’re all walking around with unhealthy guts (!) that puts us at risk of a whole host of horrible diseases, they say these tests can help us here as well. Awesome.
This all sounds fantastic, right?
These poop tests, also known as ‘microbiome testing,’ they’re supposedly going to tell you everything you need to know, and what to do about it.
AND… these companies that promote these tests will also tell you what supplements to take. Plus, you can buy the supplements you supposedly need from them as well. That’s handy.
Sounds like a winner!
I’m sure you’ve seen there are loads of different companies offering these tests and you’re probably unsure about which one to go with, if any? And you’re right to wonder.
… Because are they as good as they sound?
Should we all be having these done to improve our symptoms and our health? 🤔
But let’s back up a bit, because do you even know what your ‘microbiome’ is?
👉 The microbiome = Microorganisms, such as bacteria, fungi, and viruses, that live in and on the body, such as in our digestive tract, the gut, and on our skin.
👉 The gut microbiome = Microorganisms that live in our gut. There are more than 100 trillion microbes in our gut (1).
To test our microbiome, they can either take a sample of tissue from inside your gut (2), which is obviously very invasive (and more costly), or the more convenient and cheaper way is to analyse a sample of some (or all) of your poop (3)!
Before I go deeper, I’m going to give you a heads up – I’m going to be talking a LOT about poop or pooh or shit or faeces (feces!) or whatever you like to call your number 2s 😀
Here’s the GOOD, the BAD and the UGLY of gut microbiome (poop) testing…
The GOOD because…
Having your poop tested can provide clinically useful information that can contribute to your physician seeing the bigger picture of what’s going on, like when you’re suffering with gut symptoms.
Your physician can get your poop analysed to help them towards making or ruling out a diagnosis, such as an infection, and they can prescribe you the right medicine; if there’s inflammation in the gut; if you’re not absorbing certain nutrients; or if you’re bleeding somewhere within your gut (4,5).
Here’s an important point to note: On its own, a poop test cannot diagnose a condition – additional information is required. Like the results of a blood test cannot be used on its own to diagnose someone with a certain condition.
For example, your doctor tells you that you have high blood sodium levels. What does this tell them? Not a lot on its own. They need more info and context before they can give you a diagnosis. Because, for example, it could be that you’re dehydrated (but then why are you dehydrated – what caused it?) … and then again it could be that you have kidney disease… or, it could be for some other reason.
Here’s some more GOOD, because… there’s no denying the benefit that can come from (quality) research in this area.
Scientists doing research into the gut and its microbes is helping to grow our understanding, and how these connect to our health and disease (6) as well as our response to medications (7). So, research is helping to advance the world of medicine (8).
And science and technology are ever advancing, which is helping us improve and grow our understanding of our amazing body. Which can help us with things like, how we can better look after ourselves for longevity, and for the prevention, diagnosis and treatment or cure of diseases and health problems…but it’s early days. Future “personalised medicine” (6).
That’s the good. What about the bad?
Although we (the scientific and medical communities) know a lot, our current knowledge and understanding of our gut microbiota isn’t amazing – there’s tons more to learn.
And science does not yet know the gold standard, best technique to collect, store and analyse a poop sample, but also because the choice will depend on things like feasibility, cost, patient acceptance (9).
Depending on the reason for wanting to analyse poop, the results might not hold much value for several reasons…
Testing a sample of poop doesn’t give you the complete picture because the microbiome is dramatically different along the length of the gut (2). Poop is stored in the rectum (the section just above your anus, which is your bum hole, to put it bluntly), so the poop will be a greater reflection of this particular area of the gut compared to elsewhere, but even then, scientists have shown the microbiota found in the lower digestive tract, which is closest to the poop, is significantly different to that of the poop (3, 10).
Let’s say it’s the ascending colon, which is the first main part of the large intestine, that’s needing to be investigated for any signs of disease, then a poop sample won’t truly reflect the microbes housed there (11).
It’s like having two separate farm fields, and you want to know what’s growing in the field furthest away by inspecting the harvest from the field nearest to you❗️
On top of this, there are microbes that stick to the wall of the intestine, which means these don’t get captured in the poop and consequently get missed for analysis (8).
Also, different microbes prefer different environments, like some, known as anaerobes, don’t live or grow in the presence of oxygen. And these make up about 85% of the microbes in our gut (9). This means the culturing method needs to be appropriate. Plus, some bacteria grow faster than others.
So, there are lots and lots of different factors to consider, along with the flaws and limitations of each of the techniques and equipment that can be used. And these can provide massively different results, and in some cases incorrect results for the same sample that was tested (12)! Plus, human error and misinterpretation can get thrown into the mix too (9).
There’s also the matter of details around the chosen sample. I’ll warn you in advance that this will probably sound gross, but it’s an important point I’m making, because these questions may pop up for you prior to deciding to get tested or not...
For example, is it best to randomly scoop a tiny bit of poop for testing? Or do you collect the whole poop for testing? Or, because sometimes poop can be constipated, drier and harder at one end, but softer at the other end, does this make a difference? And if it does, then does that mean the whole poop needs to be mixed up to distribute the contents before taking a scoop for testing? Or… can a used piece of tissue paper be tested instead? Well, according to some research papers, the gold standard is to use the whole pooh, ‘homogenise’ it immediately (so it’s all blended up together), then quick frozen before being analysed (9).
“…it’s difficult to obtain accurate results from inaccurate samples” (3)!
Based on all this, along with the fact that your microbiome can change, for example due to diet, exercise, medications, medical procedures, illness, disease, stress, and life-stage (6, 13, 14, 15), what REAL benefit are you going to get from one poop test result?
A test result is a snapshot of your gut microbiome at that moment in time, and a poor snapshot at that (because of everything that I’ve just mentioned amongst other reasons). And if they tested your poop again, it could give a totally different result.
But it far worse than all this…
I’ve shown you that there are loads of flaws and limitations in the science, technology, and our understanding of our gut microbiome.
For example, we don’t know of everything that’s living in our gut. We don’t know the types and distribution of microbes throughout the gut. We don’t even know the full role and function of the microbes that we do know of, or how they interact with each other and our body. We don’t know all the chemicals and compounds they produce, their roles and what impact they have.
There are LOTS of unknowns, and we don’t know what we don’t know (16)!
So, it’s NOT yet possible to confidently say EXACTLY what a “healthy gut microbiome” looks like, because the science is undeniably young. And research has shown the microbiomes of healthy people are as individual as their fingerprints (17)!
And we CAN’T confidently say that having XYZ in your gut causes or prevents you from developing a particular disease(s). The gut microbiome and its interaction with the person is complex and much more research needs to be done.
“…we caution patients and providers that the current microbiome tests, given the state of knowledge and technology, do not provide much value in clinical decisions. Considerable research remains to be carried out to make this objective a reality” (18).
“… this area of research requires more time before major fundamental breakthroughs can be translated to general applications for the public” (6).
“…Although so-called microbiome diagnostics could become central to clinical care in the future, for the moment, knowing the specific community of your gut microbes can only satisfy curiosity rather than add value to clinical decision making” (17).
“Although there is great interest in the microbiome, there is still a long way to go before microbiome-based diagnostics become a routine part of clinical care” (9).
👉 And all of this is why physicians don’t currently recommend these tests, or support you when you ask them about getting it done – the science isn’t there yet.
Despite ALL this, companies providing commercial microbiome testing are telling you all sorts of things...
They can tell you their testing is the most advanced in the world. They can tell you that they can measure your health at the molecular level. They can extract and analyse DNA from bacteria in your poop. They can list which types and how many bacteria they’ve found in your poop and call it your “profile” or “fingerprint”.
They can make statements about your test results, like your microbial diversity is ‘normal’ (or ‘abnormal’), or that your gut is ‘healthy’ (or not), or that you have high, normal, or low levels of [fill in the blank] bacteria.
They might say you have high levels of bacteria associated with diarrhoea, but you may already be experiencing diarrhoea so you wouldn’t need a DNA test to tell you that after the fact!
They may tell you that you have high levels of ‘bad’ bacteria, such as E. coli but fail to tell you there are thousands of different strains of E. coli, where at least one type is considered to be a probiotic whilst others can make you very ill (9).
They may even tell you about things like your level of immunity, levels of inflammation and ‘cellular stress,’ your risk of leaky gut.
Then based on your results, they can tell you what to eat, what to avoid, and what supplements to take (which they happen to sell as well). And some companies also have an App that you can buy!
These tests can cost from about £160 upwards (~ $200+ USD) per test. And I’ve come across several that charge £300 (~ $380 USD) per test. Some companies recommend you take the test at certain intervals, like every month or every three months for example.
Then you buy their supplements that they recommend taking daily. And from what I’ve seen, the cheapest is about £47+ (~ $60 USD) for the month. Or ~ £569 (~ $720 USD) for the year. But you can easily spend more than this on their supplements, especially if they recommend taking several.
This means you could easily spend about £1210 (~ $1530) in a year, if you went conservatively and only had 4 tests done in a year (with daily supplements).
But on top of this, these companies may have made some recommendations that you need to eat certain foods, like gluten free, or fermented foods, that can then add to your weekly (and annual) food bill.
Then how long do you keep paying and having these tests done? … Maybe you only do a one-off test? … or a couple of tests? …or four a year? … or every month for a year … or every year for the rest of your life? And how about those supplements? How long do you take them for?
On the upside, these poop tests can be done in the comfort of your own home – no embarrassing moments when handing over the tiny poop pot to your nurse or physician. You can do the sample then post it off to the lab for testing. And wait for results… That’s if the sample doesn’t get lost in the mail like noted in many reviews, or the lab rejects the sample because it leaked.
This option may seem more appealing and quicker than going to your physician. But… On the downside…
⚠️ This could be a dangerous choice if you choose this instead of your physician, for example, if you were suffering with change in bowel habit, severe stomach pains and blood in your poop, because you’d be missing out on getting a diagnosis, and the right help and treatment that your physician can provide.
A BETTER Way…
The types of poop tests that your physician requests have scientific evidence to support their use and provides useful information that can help towards making a diagnosis or track progression.
But gut microbiome poop tests currently have no value for your physician or you, although you may find the results interesting, if not confusing as well!
These tests are more useful for scientific researchers than they are for any of us!
👉 If you’re interested in not wasting money on these poop tests, intolerance testing, and buying a load of supplements that you might not even need, if you want to avoid other common pitfalls, and if you want to know what to do instead, then I want to invite you to watch our special training now.
Best wishes to you 😀
- Lo Presti et al., 2019
- Vega et al., 2020
- Tang et al., 2020
- Pathirana et al., 2018
- Wilkinson et al., 2017
- Cani, 2018
- Selway et al, 2020
- Bokulich et al., 2020
- Allaband et al., 2019
- Zmora et al, 2018
- Mailhe et al., 2018
- Thorsen et al., 2016
- Madison & Kiecolt-Glaser, 2019
- Mailing et al., 2019
- Wilmanski et al., 2021
- Thomas & Segata, 2019
- Loughman & Staudacher, 2020
- Staley et al, 2018