Ten Things You Didn’t Know That Could Upset Your Gut

10 things you didn’t know could upset your gut

When it comes to a troublesome tummy, we can be quick to point the finger at well-known culprits such as wheat or dairy products — with some people cutting such foods out entirely.
But eliminating whole food groups from your diet is rarely what doctors advise, unless a specific allergy or auto-immune condition, such as coeliac disease, is diagnosed. And when it comes to irritable bowel syndrome-type symptoms such as bloating, abdominal pain and constipation, there are many less obvious triggers.
Here, we reveal the top gut saboteurs. Some of them may surprise you …
1. Apples

Apples are particularly high in fruit sugar
Yes, of course fruit is part of a healthy diet, but the National Institute for Health and Care Excellence (NICE) has recommended IBS patients limit fruit to three portions a day.
Apples are a particular problem for two reasons, explains Dr Steven Mann, a consultant gastroenterologist at the Royal Free Hospital in London.
‘Some people are fructose-intolerant, which means they don’t digest well the sugar in fruit. Apples are particularly high in this fruit sugar.’
Apples also contain sugars known as fermentable oligosaccharides, disaccharides, monosaccharides and polyols (collectively known as Fodmaps), which are poorly absorbed in some people’s small intestine and so ferment, triggering symptoms.
A low Fodmap diet is often suggested for people with IBS (see back page). Other fruits that have a high Fodmap content are stone fruits such as apricots and prunes.


Hormones released in response to the high saturated fat content in mayonnaise may lead to a delay in the emptying of the stomach and movement of food through the bowel, explains Dr Mann. This can cause uncomfortable feelings of bloating.

3. Branflakes
This is something of a paradox, since we’re often told that high-fibre foods such as bran are good for the bowel.
‘For those with IBS issues, such as bloating, bran can aggravate the condition,’ says Dr Mann. This is because adding a bulking agent in the form of fibre gives the bowel even more work to do, which can make symptoms such as constipation worse. Kevin Whelan, professor of dietetics at Kings College, London, says the fibre story is a complex one.
‘In the Eighties and Nineties we were telling IBS patients to eat more fibre, but now we know it’s not as simple as that. It depends on what type of fibre it is.’
NICE recommends that people with IBS should be discouraged from eating insoluble fibre (which means it cannot be absorbed by the body), including bran.
Nice says that if more fibre in the diet is needed, it should be soluble fibre (which can be absorbed) such as oats or ispaghula powder (made from the husks of plants and contained in products such as Fybogel).
So try switching that morning bowl of bran cereal for oat-based porridge. Watch out for muesli, though, as it can contain a lot of high-Fodmap dried fruit.
4. Reheated pasta
Reheated carbohydrates, such as pasta and potatoes, contain what’s known as resistant starch, which is harder for the gut to break down, says Dr Mann.
That’s because once pasta is cooked and cooled, it becomes resistant to the normal enzymes in our gut that break carbohydrates — so the gut effectively has to treat it like fibre, which can worsen IBS symptoms.
Reheated pasta may be worse than cold pasta — research has shown that the starch in cold pasta becomes even more ‘resistant’ when heated up again.
5. Coffee
The British Dietetic Association recommends drinking no more than two mugs of caffein- ated drinks a day if you suffer from IBS.

The British Dietetic Association recommends drinking no more than two mugs of caffein- ated drinks a day if you suffer from IBS
IBS: What are the symptoms of Irritable Bowel Syndrome

Consultant gastroenterologist Dr Simon Smale says people with healthy gut function can probably drink more, but those with IBS should aim to keep within recommended limits. ‘Obviously tea contains caffeine, too, but coffee is much stronger — especially coffee shop double espressos.
Caffeine can cause problems because it stimulates cell messengers which increase gut motility — so it loosens your bowel movements and can also lead to a feeling of fullness.’
6. Vegan diets
Going meat-free and dairy-free has become a trendy way of boosting your all-round health. But while a diet based entirely on plants might sound very virtuous, it may not be so saintly for your gut.
‘Vegans are a very broad church and I would say that more of them eat healthily and probably live longer,’ says Dr Smale.
‘But vegans with IBS have to be careful not to eat too many beans and grains, fruit and vegetables containing Fodmaps as they can cause bloating, pain and diarrhoea.’
Offending vegetables include onions, garlic, artichokes, mushrooms and cauliflower.
7. Alcohol
‘Booze can definitely be a trigger for IBS symptoms as it has an effect on gut motility,’ explains Dr Smale. ‘Drinking beer, for instance, may result in you having looser stools.’
And while it’s obvious that fizzy alcoholic drinks such as lager and Prosecco are more likely to leave you bloated, fizz isn’t the only booze factor bothering your gut.
‘Spirits with high concentrations of alcohol, such as gin and vodka, can delay gastric emptying which can result in pain or bloating,’ adds Dr Smale.

Booze can also trigger IBS symptoms and drinking beer may result in you having looser stools
8. Sugar-free mints

Peppermint oil capsules are a common remedy for IBS — but sugar-free mint sweets can have the opposite effect. These often contain aggravating Fodmaps such as the sweeteners sorbitol and mannitol, which can exacerbate IBS; the same is true of sugar-free gum.
Chewing gum can also contribute to wind and burping, as chewing it means you’ll take in excess air.
9. Junk food
We all have trillions of bacteria living in our gut and the balance of the different types is an area of great interest when it comes to IBS research.
As well as ‘friendly’ bacteria, some types in our guts are linked with increased inflammation, according to Tim Spector, professor of genetic epidemiology at King’s College London and head of the Great British Gut Project, and this could contribute to IBS.
According to Professor Spector, chemicals known as emulsifiers (which help mix ingredients together in some foods) are especially bad for this — killing off more helpful bacteria strains and allowing the unhealthy ones to flourish. Some research has suggested a junk-food diet can halve the number of helpful bacteria in the gut in just ten days.
10. Gluten
A well-known trigger of gut problems, gluten is a protein found in wheat, barley and rye (and so is in most bread, cakes, biscuits and pasta).
It used to be thought that gluten caused problems only in people with coeliac disease, but it’s more complicated than that.
‘There are two types of problem,’ explains Dr Smale.
‘Some people will develop coeliac disease — an autoimmune disorder where the body produces antibodies to gluten and damages the gut, causing bloating and diarrhoea. This can be diagnosed via a blood test and biopsy, and symptoms subside if the patient avoids gluten.
‘But there is another condition — where people have the same symptoms but test negative for markers in the blood test and gut damage in the biopsies — called non-coeliac gluten sensitivity.
‘These patients may respond to a gluten-free diet, but coeliac disease needs to be excluded first.’