How to improve IBS through your diet

As science discovers more about IBS, it's becoming clearer how people can limit symptoms by adapting their diets.

“Bloating, loose stools, constipation, abdominal distension, excess gas, stomach pain…” Kirsten Jackson, AKA The IBS Dietician, is listing the most common symptoms associated with Irritable Bowel Syndrome (IBS). Prior to her diagnosis in her twenties, she struggled with all of them too.

The condition is more common than you’d think. It’s estimated that around one in 10 people in the UK have IBS.

While it’s known that diet can impact the severity of symptoms, there is no one-size-fits-all approach when it comes to what to eat and what to be wary of. Something that helps one person with IBS may not help another.

“Prior to diagnosis, I tried things like avoiding fibre or gluten, meaning my diet would become quite restricted. So eventually I would fall off the wagon and then make myself feel guilty that I hadn’t stuck it out,” explains Jackson. “But none of it worked anyway.

“After diagnosis I was already a dietitian, so I had a slightly different outlook than other people. I tried the low FODMAP diet process, probiotics, various other supplements and my symptoms did get a little better, although nothing made a huge difference.

“After a couple of years I realised these sorts of tactics were not going to work and so I started to read more – that’s when I found the ‘take control’ approach. It involves sleep, movement, nutrition and mental health. By looking at all these factors, I was able to improve my gut’s tolerance to certain foods.”

You’ve probably heard of the low-FODMAP diet and how it has been used to treat a variety of stomach-related health complaints. But what does this mean in terms of foods to avoid?

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols – this basically describes a specific type of carbohydrate.

“High-FODMAP foods – like onion, bread, garlic – are broken down by bacteria in the gut and give off gas and draw in water. In people with IBS, this may cause symptoms,” explains Jackson. However, she is quick to add that “they are also prebiotics and good for the gut, so it is important that people do not simply cut them out. Instead, they need to work through the low-FODMAP process to figure out what they can tolerate.”

Aside from FODMAP ingredients, Jackson explains that caffeine and alcohol could also negatively impact those with IBS.

“Caffeine may cause looser stools and pain. Most people are aware of this but what is sometimes missed is that caffeine can worsen anxiety, which is directly linked to IBS. Plus, caffeine has around a 10-hour life span in your body, meaning it can worsen sleep. Poor sleep is also directly linked to poorer IBS management.

“Alcohol typically causes us to feel sleepy or relaxed but it actually disrupts the sleep cycles and so worsens our sleep. It is also linked to higher levels of depression and can cause looser stools, too. So even having just one drink should be a careful consideration for someone with IBS.”

‘Don’t jump to a low-FODMAP diet’

Cambridge University’s Prof Miles Parkes has carried out lots of research into IBS. In November 2021 he published a study into how different people with IBS responded to a low-FODMAP diet.

While he found that it can definitely help improve the gut microbiome of some people with IBS, he still advises against diving straight into this challenging diet.

“A low-FODMAP diet is quite a tough diet for people to follow,” says Parkes. “For many people with IBS, there are other, easier ways for them to manage it, including through dietary restriction but without needing to go all the way to a low-FODMAP diet. So typically, for example, a low-fibre diet will get about half of people better. And if it doesn’t, you might try a lactose exclusion diet or try avoiding gluten and wheat.

“If none of those tactics work, then yes, a low-FODMAP diet is a good option. But experts go there as a second-line dietary therapy rather than advising it first.”

For Jackson, finding the right diet has involved trial and error. “My diet now includes a large variety of foods and is high fibre. I’ve found that I cannot tolerate too much lactose but enough to allow me to have milk with breakfast. I also found that beans and pulses in larger amounts are an issue. But this is very personal to me.”

The link between diet, mental health and IBS

As Jackson explains, she sees good mental health as an important factor in an IBS treatment plan – diet alone is not enough. The science backs this up – with a growing number of research papers highlighting just how diet and mental health are inextricably connected. Could helping one also help the other?

Parkes and his team conducted a wide-scale study investigating the relationship between mental health disorders and IBS and found that the same gene variants that signify IBS are also commonly found in people with mental health disorders.

“Anxiety, neuroticism and depression are way out in front in terms of being genetically similar to IBS.

“We’re able to say with some level of certainty that essentially IBS and anxiety are coming from the same place, they share a genetic origin. People who are at risk of one are much more at risk of the other as well.”

Whether this means you could treat some mental health disorders and IBS using your diet is still to be discovered, says Parkes. Though there is encouraging research that highlights that increasing your gut microbiome could help both.

Prof Felice Jacka, director of the Food and Mood Centre at Australia’s Deakin University, has carried out research which has established a link between improved microbiome and the alleviation of anxiety symptoms.

“Our new knowledge regarding the role of the gut bacteria in mental and brain health represents a major step forward. And diet is one of the most important factors affecting the health of the gut and its bacteria – with impact happening very quickly.

“There is a huge amount of effort going into research in this field around the world now. I expect that it won’t be long before we have some very important insights and tools by which we can manipulate our gut health to improve our mental and physical health. The most important of these will involve food, but probiotics and prebiotic supplements and fermented foods are likely to also be part of this approach to prevention and treatment.”

If you’re unsure as to whether you have IBS, the most important thing, say the experts, is to seek professional help. “You must go and get tested if you have any digestive symptoms,” says Jackson. “Conditions like coeliac disease, IBD, infections, parasites and bowel cancer can display the same symptoms as IBS,” so it’s crucial to pinpoint what’s causing the issue in order to manage it.

Originally published July 2023