What causes bloating?
Waistband suddenly feeling tight? It might not just be that you’ve eaten too much.
Like hundreds of thousands of Britons — women and men — you could be suffering from stomach bloat, which can be triggered by anything from fluctuating hormones to eating reheated pasta.
Sometimes it can be caused by an innocuous glass of water.
Often, bloating is caused by irritable bowel syndrome, a condition that affects a staggering one in seven Britons (caused by an oversensitive gut, it leads to problems with bowel function and can trigger bloating, as well as cramps, constipation or diarrhoea).
While most people’s stomachs may swell just a couple of inches, others’ can actually double in girth in just one day, only to ‘deflate’ overnight until the next attack.
Not everyone’s stomachs will distend in this way — instead they will report suffering an uncomfortable swollen feeling.
So what could be behind your fluctuating waistband and bloated feeling — and what can you do about it? We asked the experts for their advice…
For some people, bloating strikes only when they eat out, says Luci Daniels, a registered dietitian in London and former chair of the British Dietetic Association.
‘I have patients who say they only get tummy trouble or bloating when they eat pasta, rice or potatoes in a restaurant.
‘This is often because these foods have been re-heated.’
It seems re-heating starchy food changes its molecular structure, turning it into ‘resistant starch’. This cannot be digested in the small intestine but passes into the large intestine — the bacteria that helps break it down produces gas, hence the bloating.
Some people find it harder to digest resistant starch than others.
‘If you do notice this, you don’t need to avoid these foods — just make sure they’re freshly cooked,’ says Luci Daniels.
Processed foods such as ready meals and part-baked breads such as baguettes also tend to have more resistant starch.
Hormonal fluctuations during a woman’s monthly cycle are a common trigger for bloating.
But while many women might put it down to ‘fluid retention’, the cause is actually relaxed muscles, explains Leila Hanna, consultant gynaecologist and obstetrician at BMI The Sloane Hospital, London.
‘Many women find they are bloated before their period, and this is due to an increased level of progesterone,’ she says.
‘During ovulation, the ovaries produce more progesterone and it causes muscles in the abdomen to relax. Everything (i.e. the organs) isn’t packed in as tightly as usual, causing a woman to look bloated. It tends to get worse just before the menopause.’
The muscles in the bowel also relax, meaning they are less efficient at moving food along the gut. This can cause constipation, triggering further bloating. It’s possible to overcome this by eating more fibre, says Ms Hanna.
When you chew gum you swallow more air, which increases the risk of bloating, says Peter Whorwell, a professor of medicine at Wythenshawe Hospital in Manchester, and a leading authority on irritable bowel syndrome.
‘Sugar-free versions are worse as they contain ingredients such as sorbitol and xylitol which are fermented by bacteria in the gut and may also cause bloating — double trouble,’ he adds.
‘These ingredients are also found in sugar-free drinks.’ Eating quickly can also trigger bloating or make it worse, adds Professor Whorwell.
‘As we eat we swallow roughly the same amount of air as we do food,’ he says.
‘Therefore, gulping down food quickly or large amounts in one bite means you’ll swallow more air and increase the risk of bloating.’
A HEALTHY DIET
‘Anything “healthy” is often a cause of bloating,’ says Professor Whorwell.
‘High-fibre foods, such as cereals, beans and pulses cause bloating by fermenting in the gut. Don’t force yourself to eat lots of brown bread, bran and vegetables if they are crucifying you.’
Healthy snacks are another problem, adds Luci Daniels.
‘Many people spend all day snacking on large amounts of fresh fruit, nuts and seeds — all of which ferment in the bowel and cause problems in both healthy people and those with irritable bowel syndrome. Edamame beans are notorious for causing bloating, yet people eat them because they’re healthy.’
Dieting can also cause bloating if you stick to a high-protein diet such as the Atkins or Dukan, explains Luci Daniels.
‘Faddy diets don’t help when it comes to bloating,’ she adds.
‘People wonder why they are bloated and constipated, yet they are on a high-protein diet so getting very little fibre, which is what we need to go to the loo regularly.’
A lack of ‘good’ bacteria in the gut can lead to bloating. Good bacteria, also known as the gut flora, help to stimulate the digestive process and keep the gut cells healthy.
But taking antibiotics, or suffering from food poisoning, can disrupt the delicate balance of bacteria, causing bad bacteria to proliferate, explains Marianne Williams, a specialist allergy and IBS dietitian.
This imbalance means you’re more likely to be sensitive to foods that ferment in the gut, causing bloating and gas. It’s thought that probiotics can help restore the balance of good bacteria again.
‘There is clearly a link between the brain and the gut — and so angst can make any digestive symptoms more severe,’ says Professor Whorwell.
In irritable bowel syndrome, this connection is exaggerated and the gut is oversensitive to factors such as stress, diet, hormones and bacteria.
In fact, stress is one of the biggest triggers for the condition, says Professor Whorwell.
‘I see many patients who say they’ve always had a bit of a funny tummy but the problem has got really bad since a stressful event a few years back.
‘It’s likely they always had a predisposition to stomach problems, but a stressful event has finally set them off.’
UNDIAGNOSED COELIAC DISEASE
Coeliac disease, which is an allergy to gluten, can cause uncomfortable bloating, although it’s not clear why.
‘Whereas irritable bowel syndrome is basically a plumbing problem, allergies are caused by a problem with the immune system,’ says Marianne Williams, a specialist allergy dietitian.
‘The problem is the symptoms can be very similar to irritable bowel syndrome and many patients go undiagnosed for years.’
Other common symptoms that might help differentiate coeliac disease from irritable bowel syndrome include unexplained anaemia, fertility problems and joint pain.
As many as half a million Britons are thought to suffer from undiagnosed coeliac disease.
‘If you think you have a food intolerance or allergy, keep a food diary for seven days, noting when exactly you ate, what symptoms you had (if any), when they appeared, and grade them from zero to four in terms of severity,’ explains Wiilliams.
Professor Whorwell advises if your bloating doesn’t seem to subside at night, or if it’s getting worse, always see your GP to rule out more serious conditions.
One of the most common causes of bloating is IBS.
To find out what triggers it, Professor Peter Whorwell gets his patients to wear a ‘Bloat-ometer belt’.They keep it on for 24 hours and a computer monitors their girth every hour.
We asked two women who suffer from IBS to try it out…
WAIST: Morning, 27in; Lunchtime, 33in; Evening, 33in
Terri Taylor, 21, is a student nurse from Huddersfield.
My stomach was flat when I woke up, but by the end of a hectic morning at work it had expanded.
For breakfast, I had two Weetabix and two slices of white toast, and by the time I got on the ward ten minutes later I felt really uncomfortable.
Then when I got home at 2.30pm, absolutely starving, I had a big plate of beans on wholemeal toast, which pushed it up by another inch (to 32in).
Just a few minutes after eating, I had stomach pains and had to loosen my clothes.
That night I had to study for my nursing finals. I finally ate my dinner of wholemeal pasta and vegetables around 9.30pm, but left a quarter of it as it made me feel so ill. Overnight my stomach went right down to 27in. If only it would stay that way.
Professor Whorwell says:
What triggers the bloating can vary widely — some patients literally put food in their mouths of have a glass of water and their stomachs will distend.
Terri’s bloating seems most likely to be linked to eating and stress. The fact her girth shot up by 6in in a morning and didn’t then vary drastically throughout the day suggests stress is likely to be a key factor. Other peak periods of bloating appear to coincide with meal times.
Patients often ask me why they can eat, say, tomatoes one day and be fine, yet the same food will cause them to bloat a day later.
The best thing is to look at it like a ‘points’ system, and you have to reach 100 points before you bloat. Your stress that day might account for 30 points and tomatoes 60. So you’ve not reached 100 and you’re fine. The next day, you’ll eat tomatoes but stress might account for 70, pushing you into the bloating zone.
‘I suspect that Terri’s high-fibre diet may be making her worse. Beans, as Terri ate, are notorious for causing bloating and gas, and many patients complain that and pulses, lentils, chickpeas can crucify them.
‘That’s because they produce a lot of gas and IBS patients retain more gas than other people (because they’re not so good at getting rid of it).’
Wendy Jeffries, 47, is a medico-legal secretary from Manchester. She is married with two sons.
WAIST: Morning, 33.5in; Lunchtime, 52in; Evening, 56in
As soon as I had breakfast, a bowl of Special K around 10am, my waist expanded to 45.5in. Things went from bad to worse at lunchtime. I’m a vegetarian and my only option at work was a jacket potato with baked beans. It sent my measurement soaring to 52in.
I still felt pretty terrible when I got home from work, so I had a quick lie down. After this I went back down to 48in. That was undone by eating dinner, though.
I only had a very plain salad of tomatoes, lettuce and cucumber, washed down with fizzy water, but my stomach became the biggest it had been all day — 56in.
Sometimes I actually look pregnant.
But by the time I went to bed, I had shrunk down to 36in.
Professor Whorwell says:
From looking at Wendy’s results, it seems very likely that her bloating is triggered by an abnormal abdominal reflex — that she has abdominal muscles that relax more easily and distend the stomach more.
The job of these muscles is to relax when we eat a big meal — otherwise we would be very uncomfortable — but in patients with irritable bowel syndrome this may be exaggerated.
She is severely bloated by the evening — much more than would be expected considering the volume of food she’s eaten. She eats a lot of fibre and vegetables, which can make matters worse, and fizzy drinks should be avoided.
For patients whose bloating appears to be due to problems with the abdominal muscle reflex, a behavioural therapy called biofeedback can help.
The patient wears the bloating belt and uses various physical processes, such as relaxation, to make their girth reduce.