This common cause of bloating has nothing to do with food

Feeling bloated could be an abnormal muscle response. Photo / Getty Images

Abdomino-phrenic dyssynergia may be to blame for frequent bloating in many people. There are ways to manage it and multiple causes.

I get bloated after most meals. It’s so embarrassing – I’m always wearing elastic pants when I go out to eat. Why does this happen to some people?

Most patients with bloating who come to see me in my gastroenterology clinic think it is because something from inside – such as increased gas – is pushing their bellies outward. This drives them to try changing their diets.

Sometimes that helps. Often it doesn’t.

For many people, frequent bloating has little to do with gas or stool; it could be an abnormal muscle response, researchers in my field have come to understand.

If we think of the abdominal cavity – or the hollow part of the belly containing internal organs such as the liver and stomach – as a cardboard box, the issue may not be what’s inside the box, but rather the box itself.

And if we started pushing the lid of the box downward, something would have to give.

For many people, during bloating episodes, the diaphragm – or the muscle supporting the lungs between the abdominal and thoracic cavities – descends, and the abdominal wall muscles relax, pushing everything within the abdominal cavity, such as the bowels, forward.

This response – called abdomino-phrenic dyssynergia – may seem counter-intuitive; after all, bloating often occurs with meals. So people try changing their diets. And for some, eliminating certain classic triggers such as onions or garlic can improve symptoms, but many are left wondering why that didn’t fix anything.

The good news? There are other ways to help.

Abdomino-phrenic dyssynergia

Some amount of bloating is normal and universal. Usually, it is infrequent and transient – but if it happens often and affects your quality of life, talk to your physician.

Sometimes I find a quick and easy solution, such as stopping artificial sweeteners and chewing gum, or changing my patients’ continuous positive airway pressure, or CPAP, masks. But there are many other causes of bloating, including foods. Medical conditions such as irritable bowel syndrome may also play a role.

Abdomino-phrenic dyssynergia can happen after eating, which is why food tends to be the first thing blamed. For instance, many people complain that lettuce gives them uncomfortable gas and bloating. But a 2019 study found that the gas produced by fermentation of lettuce via our gut microbiomes is minimal.

CT scans of the abdomen revealed that people who complained of bloating after eating lettuce had no significant changes in their intestinal gas compared to before eating lettuce. Instead, their scans showed the hallmarks of abdomino-phrenic dyssynergia: a descending diaphragm and the protruding abdominal wall muscles that forced their bowels from resting comfortably under the ribcage to move closer to the belly button.

What to try for bloating

Consult your doctor: People are sometimes embarrassed by their bloating or brush it off as no big deal. It’s important to talk openly with your doctor about what’s concerning you and not delay. The first step is to ensure we are not missing anything serious, including celiac disease or ovarian cancer.

Assess dietary triggers in a systematic fashion: Lactose intolerance or other classic food offenders such as cruciferous vegetables, lentils and beans account for bloating in as many as a third of patients. I tend not to recommend restricting too many foods – such as with a trial of a low-FODMAP diet – without the guidance of a registered dietitian. Make sure you have the right team with you and are assessing possible triggers in a systematic, trackable fashion.

Be open about your bowel habits with your doctor: Sluggish bowels are an important source of bloating and may be easily treated with medicine. Your physician can also help evaluate if your pelvic floor may be aggravating your symptoms. Remember the cardboard box? The pelvic floor is the bottom of that box, and it, too, can contribute to bloating when those muscles don’t coordinate appropriately.

Discuss biofeedback training: if simple dietary changes don’t help and constipation is not an issue, you may need to think about abdomino-phrenic dyssynergia. A gastroenterologist can best evaluate. Two randomised placebo-controlled trials showed that special kinds of physical therapy exercises, called biofeedback, can train patients to mobilise their diaphragm and reduce bloating. This involved manoeuvres to elevate the chest and contract the abdominal wall. After four weeks, participants who did these exercises before and after eating experienced 66% symptom improvement.

This kind of biofeedback may not be available at every medical centre. Some scientists have suggested that diaphragmatic breathing exercises, which involve related manoeuvres and can be practised at home independently, may also be of use to patients with bloating, but more research is needed to confirm the benefit.

What I want my patients to know

When a woman who has undergone menopause comes to my clinic complaining of new bloating, a little alarm goes off in my mind. That alarm gets louder if she tells me that the bloating is there all the time – even first thing in the morning. Bloating and distension can be one of the earliest signs of ovarian cancer. Ovarian cancer is relatively rare, at least when compared with other cancers in the United States, but I take new bloating symptoms like this one very seriously because ovarian cancer is also one of the easiest cancers to miss at an early stage.