What 2.8 Million People's DNA Says About IBS

October 25, 2026•8 min read

You know the appointment. The tests came back clear, which was meant to be good news, and somehow it didn't feel like good news at all. You were told there's nothing sinister, handed a leaflet about fibre, and sent back out into a day where your stomach was still swollen and still hurting and you still couldn't plan anything past four o'clock. Somewhere on the way home a thought arrived that's never quite left. If nothing showed up on the tests, is anybody actually treating something real?

There's a piece of research that answers that question from an unexpected direction, and it does it at a scale that's hard to argue with.

The research: 35 places in the genome, and none of them are imaginary

An international team, with Professor Mauro D'Amato as senior author, published the largest genetic study of irritable bowel syndrome (IBS) yet run, in the journal Gut in July 2026. They pooled genetic and health data from 2,775,539 people across 22 biobanks around the world, and compared the DNA of people with IBS against the DNA of people without it.

The clever part is how they handled the definition problem. IBS gets defined differently depending on who's doing the defining, so rather than picking one definition and hoping, the team deliberately ran more than one side by side. That's what the word "cross-definition" in the title means, and pooling them that way is what gave the study the statistical power to see signals that smaller studies simply can't pick up.

They found 35 separate regions of the human genome associated with IBS risk. Several of those regions point exactly where a gut-brain story would predict: to the brain, and to the enteric nervous system, which is the dense mesh of nerves running through the wall of your gut and is sometimes called the second brain. But the team also found something nobody was looking for. There was a strong overlap between the genetics of IBS and the genetics of heart and metabolic health, and in particular with triglycerides, a type of fat that circulates in your blood and shows up on a standard cholesterol test. Using methods designed to test cause rather than coincidence, the strongest signal sat in a gene called GCKR, which acts as a control switch in the liver for how the body handles sugar and fat.

Be fair to the study about what it is. A genome-wide association study tells you which stretches of DNA turn up more often in people who have a condition. It can't tell you what any one person's genes are doing, and it says nothing at all about treatment, because nobody in it was treated. It's also an international pooled sample rather than a UK study, and the full paper sits behind a paywall, so what's here comes from the abstract and the research announcement published alongside it.

Why this matters for you. IBS is still routinely diagnosed by ruling other things out, which is exactly why so many people come away feeling they've been handed a label instead of an explanation. A study this big, finding this many consistent genetic signals, is another piece of hard evidence that IBS is a real biological condition with real machinery behind it. We looked at the same question from the blood-test angle in an earlier post on biological markers, and the picture keeps getting firmer.

It's worth saying plainly what it doesn't mean. Thirty-five genetic regions don't add up to a genetic destiny. They shift risk, they don't set outcomes, and none of this makes your symptoms less changeable. The triglyceride finding is about shared biology across a very large population, not a reason to change what you eat. If you've questions about your cholesterol or your triglycerides, those belong with your GP, and any change to your diet belongs with a dietitian.

Why the nervous system finding is the one that matters to you

The triglyceride result is the headline, and it's genuinely new. But for anybody living with IBS, the quieter finding matters more. Independent genetic evidence, drawn from nearly three million people, keeps pointing to the brain and the enteric nervous system. That's the wiring of the gut-brain axis turning up in the DNA itself.

That axis is what's doing the work during a flare-up. Your gut and your brain talk constantly, in both directions. In IBS that conversation runs louder and more reactive than it needs to, so ordinary gut activity that would go unnoticed in somebody else gets amplified on the way up and arrives as pain or urgency. That's visceral hypersensitivity, and it's a change in how signals get processed rather than a change in character. Once it's happening, a loop forms: symptoms breed anticipation, anticipation breeds watchfulness, watchfulness sharpens the signal, and round it goes.

Genetics can load that system. It can't run it minute to minute. What runs it minute to minute is the state your body's in, and the state is the part you can work with. That's why the gastroenterology guidelines take gut-brain therapies seriously. The British Society of Gastroenterology gives gut-directed hypnotherapy a strong recommendation, and NICE lists it as an option for IBS that hasn't responded to first-line treatment after twelve months.

The work I do is cognitive behavioural hypnotherapy, which means cognitive behavioural therapy, mindfulness and gut-directed hypnotherapy working on the same maintaining cycle rather than choosing between them. Cognitive behavioural therapy goes after the thoughts and the habits that keep the loop turning. Mindfulness changes what you do with a sensation once you've noticed it. Gut-directed hypnotherapy uses focused attention to work on how the gut and the brain are talking to each other. They pull on the same loop from different angles, which is why putting them together tends to do more than any single strand on its own.

Your top tip this week

Give your gut's own nervous system a signal before you eat, not after. This study puts the enteric nervous system back at the centre of the picture, and that network takes its cues from the state your body is in. Most of us eat on the move, mid-email, or braced for whatever the meal might do. So before your next meal, sit down and take sixty seconds of slow breathing where the out-breath is longer than the in-breath, roughly four counts in and six counts out. That pattern nudges the body towards its rest-and-digest setting, which is the setting digestion was designed to happen in. The study didn't test breathing, so treat this as a sensible application of what the finding points to rather than a result from the paper. It costs a minute, it needs no appointment, and it's one of the few things you can do at the exact moment your gut is about to be asked to work.

Voices

"Our findings support a more integrated view of IBS that extends beyond the traditional gut-brain axis."

Professor Mauro D'Amato, senior author of the study, quoted in the CIC bioGUNE research announcement, July 2026.

The takeaway

Nearly three million people's DNA now says what you've been saying all along: this is real, it has biology behind it, and it involves your nervous system rather than your imagination. That doesn't mean you're stuck with it. Genes set a starting position. The gut-brain loop that keeps symptoms turning over day to day is the part that responds to being worked on.

Wherever you are right now

If you haven't had a firm diagnosis yet, start with your GP. Gut symptoms have several possible causes and some of them need ruling out, so get that done first. Clear tests aren't a dead end. They're the starting line.

If you were diagnosed a while ago and you're still struggling, you're exactly who the guidelines had in mind for psychological approaches. Try the minute of slow breathing before one meal a day and see what you notice. And if the genetic angle has you wondering about your own family, that's a question for your GP rather than for a home DNA test.

If you're a GP or a gastroenterologist reading this, the cross-definition design is the interesting part, and the referrer brief for gut-directed hypnotherapy, with the guideline positions set out and their limits stated, is available on request.

If you'd like the science in plain English once a week, plus one thing to try, join Gut Feelings at mindyourguts.co.uk/free-relaxation-page. The free relaxation recording comes with it.

About Mind Your Guts

Mind Your Guts is the Irritable Bowel Syndrome (IBS) blog written by Kathryn Dunn, a cognitive behavioural hypnotherapist based in York and working online. One piece of gut-brain research each week, in plain language, and one thing worth trying. More at mindyourguts.co.uk/gut-feelings.

Twelve Minutes of Calm. A free relaxation recording, about twelve minutes, for the times you want to feel calmer. It's a general relaxation recording rather than a treatment for anything. Download it at mindyourguts.co.uk/free-relaxation-page and you'll also join Gut Feelings, my weekly email, which carries each new post to your inbox along with a bit extra.

Hypnotherapy works alongside conventional medical care, never in place of it. This blog shares research for general information and is not a substitute for medical advice. Only a doctor can diagnose IBS. Always consult your GP or another relevant health professional. If your symptoms are new, changing, or accompanied by warning signs such as bleeding, unexplained weight loss, or persistent pain, please see your GP.

Sources

Kathryn Dunn

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