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With the arrival of (kinda) affordable microbiome tests, "should I get my microbiome testes?' is a question I hear a lot.

Disclosure: this is just my opinion, but from what I know, my answer is… not yet. 

Here’s why.  

First, we still don’t know what the ideal microbiome looks like. Yep, really.

To quote Dr Rob Knight says (an expert who has analysed thousands of people’s microbiomes), “there’s a lot of different healthy microbiomes and they have almost nothing in common”. So just because yours is different from your best mates, that doesn’t mean it’s bad.

Second, your microbiome is dynamic, changing with diet, exercise, seasons, location and factors like antibiotic use. So when you test your poop you’re just taking a snapshot, and seeing what is there at that point in time. Imagine it like a single photo.  That's all.

Third, it’s not clear if the bacteria in your stool give an accurate reflection of what’s going on in the rest of your gut. At most, we’re seeing what bacteria are hanging out in your poo. 

Microbiome tests can characterise bacteria as good or bad but it’s not that simple. A microbe’s behaviour can be helpful or harmful depending on what other microbes are around, and in what numbers. It’s like being at a party and your ex turning up – suddenly your behaviour changes. You can have a pathogenic strain living peacefully, and that wouldn’t mean you need to get rid of it. 

At present, a microbiome test can tell you what’s there, but not what that means, or what to eat as a result.

To quote Rob again, “The definition of a healthy gut microbiome may be context-dependent and highly personalised. As a result, we can’t define what a healthy microbiome is based on whether specific organisms are present”.

These tests have great potential but there’s lots to learn before we can use them in a truly personalised way. If you want to take one, then remember their limitations, and that you’re simply looking at who is there at that point in time.

Now, if you do want to spend some money on gut bacteria, consider taking a look at Chloe Russell’s wonderful prints (she took the wonderful photo on this post) available here.


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