It is almost never "excess gas"
It is the explanation heard most often and one of the least accurate. The amount of gas in the abdomen of someone with distension is usually normal.
What goes wrong is different: how that gas is distributed, how efficiently the bowel transports it and how intensely it is perceived. That is why treatments aimed only at "removing gas" work so poorly.
Bloating and distension are not the same
Bloating is the sensation of pressure or fullness. Distension is the real, visible increase in abdominal girth, the belly that grows through the day. Many patients have both, but telling them apart guides the diagnosis considerably.
What does need ruling out
Before labelling anything, several specific causes deserve checking, because a number of them have specific treatment.
- Irritable bowel syndrome, by far the commonest cause
- Constipation, which patients often do not recognise as such
- Coeliac disease, mistaken for this for years
- Lactose or fructose intolerance, where the pattern suggests it
- Small intestinal bacterial overgrowth, in selected cases
- Abdominophrenic dyssynergia, an uncoordinated reflex of the diaphragm and abdominal wall
- Disorders of gastric emptying
That penultimate one deserves a mention: it explains many striking cases, is treatable with breathing and postural retraining, and is barely known outside specialist practice.
SIBO: it exists, but not as it has been told
Small intestinal bacterial overgrowth is real and treatable. The problem is how it has become a label of general use.
The breath test has a notable false positive rate. Used as screening for everyone with a bloated abdomen, it produces many diagnoses that are not, and with them unnecessary courses of antibiotics.
It makes sense to investigate when there are specific reasons: known motility disorders, previous abdominal surgery, diarrhoea with evidence of malabsorption, or certain long-term medications.
It makes no sense to request it upfront for everyone, to repeat it every few months, or to string together treatments without revisiting the underlying diagnosis.
The tests that cannot inform a decision
It is worth being blunt here, because this is where patients' desperation is most exploited.
- IgG food antibody tests. They have no validity for diagnosing intolerance and scientific societies advise against them. They detect exposure, that is, that you have eaten the food
- Hair sample intolerance tests and similar methods. Without scientific basis
- Commercial microbiome analyses. Interesting in research, but they cannot currently inform individual clinical decisions
The rule I apply
I request a test when its result will change what we do, and not before. If a test will not alter treatment, all it produces is an invoice and anxiety.
The problem with diets that keep narrowing
A pattern I see often: the patient removes a food, improves for a few days, the bloating returns, they remove another, and so on for months. A year later they eat six things and feel the same.
Dietary interventions work, but in phases and with orderly reintroduction. Following a restrictive diet indefinitely and unsupervised impoverishes the diet, alters the gut flora and adds a new problem to the original one.
If you have reached a point where food has become a constant source of worry, it is worth saying so in clinic. It is more common than it seems and it changes the approach.
What can be done
- Identify and treat the specific cause, which almost always exists
- Correct underlying constipation, which improves distension faster than anything else
- Phased dietary intervention, supported and with reintroduction
- Targeted antibiotic treatment when overgrowth is genuinely confirmed
- Breathing and postural retraining in abdominophrenic dyssynergia
- Drugs for visceral hypersensitivity when perception is the main component
Why it is worth reviewing calmly
Many people arrive at this clinic worn down: years of increasingly narrow diets, expensive tests that led nowhere and one supplement after another, feeling that nobody has taken seriously something that shapes their daily life.
There is almost always an identifiable explanation and a treatment that makes sense. And it almost always involves doing less, not more.
If you have had bloating for some time and have accumulated tests and diets without a clear diagnosis, it is worth reviewing the case from the beginning.