Why You're Still Bloated —
and why the advice you've been given isn't working.

You've cut out gluten. You've tried dairy-free. You've bought the probiotics, taken the digestive enzymes, eaten more slowly, avoided the foods that seem to trigger it. And you're still bloated.

Not occasionally bloated after a big meal. Chronically, persistently, sometimes painfully bloated — in a way that doesn't match what you're eating and doesn't respond the way it should to the things you've tried.

This is one of the most common presentations I see. Bloating is a symptom, not a diagnosis, and this post goes through the contributors that are worth looking for, with how strong the evidence is for each. First, though, two things that come before any of them.

What the evidence says first

In 2025, European gut specialists published a consensus on functional bloating and abdominal distension (Melchior 2025, ESNM/UEG). Two parts of it matter here, and I'll give you both.

The causes are several, not one. It names:

• A gut that is more sensitive to normal amounts of gas (visceral hypersensitivity).
• An abnormal reflex between the diaphragm and the belly wall (abdomino-phrenic dyssynergia): the belly pushes out instead of the diaphragm rising.
• Problems with how the gut moves (dysmotility).
• Changes in the gut microbes (dysbiosis).

Tests usually aren't needed. In the consensus's words: “In the absence of alarming signs or any relevant finding, clinical laboratory, imaging or endoscopic tests are unnecessary.”

The treatments it lists are:

• a low-FODMAP diet;
• limiting lactose;
• probiotics;
• peppermint oil;
• gut-directed therapies: CBT and gut-directed hypnotherapy, and breathing-based biofeedback for the diaphragm reflex;
• several prescription options your GP can discuss.

If you haven't tried these properly, they come first. They aren't “just symptom management”; they're what the evidence supports.

Contributors worth looking for

When first-line steps haven't worked, these are the contributors I look for. None of them is a diagnosis on its own.

Changes in the gut microbes

A 2025 study of 42 adults with functional bloating found a high score on a commercial stool dysbiosis index in 90.5% of them, and lower levels of several beneficial bacteria in most (Akkoyunlu 2025). Grade: uncontrolled case series. There was no comparison group of people without bloating, so it can't show that these changes are more common in bloating than in anyone else, or that they cause it. The consensus lists dysbiosis as one contributor among several.

Two people with the same bloating can have different microbial findings, which may be one reason the same probiotic helps one and not the other. That's a reasonable idea, not a tested one.

Infections and organisms worth ruling out

H. pylori is worth testing for if you have upper-gut symptoms. Your GP can do a breath or stool antigen test and treat it.

Blastocystis turns up on comprehensive stool tests often. It is also found in many people with no symptoms, and whether it causes them is still debated. Grade: uncertain.

Candida is often blamed for bloating, fatigue and brain fog through products such as acetaldehyde. Grade: mechanistic and untested for gut symptoms.

The GI-MAP uses PCR (DNA) testing. I treat what it finds as leads to confirm, not diagnoses.

Digestive enzyme output

Pancreatic elastase, measured on the GI-MAP, reflects how much digestive enzyme the pancreas is making. It's worth checking if bloating comes with fatty or loose stools, visible undigested food, or symptoms that are worse after fatty meals. A low result needs GP follow-up, not just enzymes. Grade: established test; elastase below 200 µg/g suggests, and below 100 µg/g indicates severe, pancreatic insufficiency (common laboratory interpretation bands).

Low stomach acid: less often than you'd think

This page used to call low stomach acid a common cause of bloating. I've changed that. Low acid is real, but it comes from atrophic gastritis (mostly H. pylori), stomach surgery or acid-suppressing drugs, not from age. There's no trial showing it causes bloating in people without those conditions. Grade: mechanistic and untested.

The GI-MAP doesn't measure stomach acid. If low acid is a real possibility (unexplained low B12 or iron, years on a PPI), the blood screen is pepsinogen I/II with gastrin-17 and H. pylori antibodies. More on that in Low stomach acid: what's real, what isn't, and how to check.

Gut barrier

The idea is that when the gut lining is leakier than it should be, bacterial products such as LPS and food proteins get through, driving low-grade inflammation and a gut that reacts to more foods over time. Grade: mechanistic.

Raised permeability is associated with several conditions, but cause and effect aren't established. No stool marker, zonulin included, measures it directly. More on that in intestinal permeability.

Stress and the gut-brain connection

The gut and brain talk to each other through the vagus nerve, the gut's own nervous system and hormones. The consensus's first-listed mechanism, a gut that is more sensitive to normal amounts of gas, is part of this. That's why gut-directed hypnotherapy and CBT have a place in treatment.

The table below is a model of how long-term stress hormones are thought to affect digestion. It is drawn mostly from physiology and animal work, and none of it is something a test of yours measures directly.

Grade: mechanistic. A DUTCH test shows one day's cortisol pattern. It can be useful context, but it doesn't diagnose a cause of bloating.

Where testing fits

The consensus is clear that most people with bloating don't need tests. So why do I test at all?

For people whose bloating hasn't responded to the first-line steps above, I test to look for treatable contributors: H. pylori, low pancreatic enzyme output, an infection, or a pattern that makes one dietary approach a better first try than another. Grade: not trial-tested. No trial has shown that testing in this situation leads to better outcomes than working through the consensus treatments in order. I think it's reasonable when those have failed, and I'd rather say so than claim testing is the only way.

How I work

My five-test programme includes Regenerus blood chemistry, the GI-MAP stool analysis, the DUTCH Plus hormone test, an organic acids test and an HealthBeings IgG food panel (286 foods). For bloating that hasn't responded to first-line steps, the GI-MAP is usually where I'd start.

From those results the next step is chosen for your findings, alongside the treatments the evidence already supports. It doesn't replace them.

Sources

1. Melchior C et al. European consensus on functional bloating and abdominal distension: an ESNM/UEG recommendations for clinical management. United European Gastroenterol J 2025;13(9):1613–51. PMID 40844856. doi:10.1002/ueg2.70098
2. Akkoyunlu DS et al. Functional abdominal bloating is associated with gut microbiota dysbiosis and altered intestinal barrier function. In Vivo 2025;39(6):3320–32. PMID 41167655. doi:10.21873/invivo.14130
3. NICE. Suspected cancer: recognition and referral (NG12).

Updated 5 October 2026: alarm symptoms added; the 2025 study now cited with its limits; low stomach acid regraded; “why testing changes everything” replaced with what the evidence says about testing.