From bloating and stomach pain to constipation and diarrhoea, most of us are familiar with the main symptoms of irritable bowel syndrome (IBS). According to research from the supplement brand Dr Vegan, an estimated one in four of us here in the UK live with the condition, which is why it’s becoming more common to hear about people navigating life with IBS. At one point, it was even a (dubious) TikTok trend.

But despite this growing awareness, there’s still a lot we don’t know about IBS. In many cases, that’s down to research. For example, we know women are more likely to be affected by IBS than men, but we don’t know what causes it in the first place; as things stand, it’s been linked to food passing through the gut too quickly, oversensitive nerves in the gut, a heightened immune system and genetics. But in other cases, that’s simply down to how complex IBS really is.  

While many of us assume IBS to be solely related with the gut and digestive system, its co-morbidities – ie conditions closely associated with IBS – can lead to symptoms that pop up throughout the body. So, to give you the lowdown on some of these symptoms, we asked Shona Wilkinson, an IBS expert and registered nutritionist for Dr Vegan, to talk us through what you need to know. 

Research into the link between IBS and sleep issues remains limited, but some studies have shown that sleep disturbances are more common in people with the condition.

So, what’s driving this? Well, several explanations have been suggested. For one thing, pain is thought to play a role – when you’re dealing with stomach cramps, bloating and general digestive discomfort, you’re more likely to find it hard to fall asleep and wake up frequently throughout the night. Disruptions to the gut microbiome – also known as dysbiosis – could also play a role due to the impact this can have on circadian rhythm, and the stress and anxiety commonly associated with IBS can also disrupt sleep.

Wilkinson suggests that the low serotonin levels in people with IBS could also cause issues. “Serotonin plays an important role in our sleep, as well as our general day-to-day mood,” she says. “Our bodies convert serotonin into melatonin, which is a hormone that helps us fall asleep at night. With IBS-sufferers often experiencing low levels of serotonin, this may also affect the quality of their sleep.”

Research has shown that people with IBS – specifically those who struggle with constipation – are more likely to have low levels of serotonin, which has links to conditions such as insomnia and depression (the latter of which people with IBS are at increased risk of). But more work needs to be done until we can say for certain why so many people with IBS deal with sleepless nights. 

According to a 2017 paper published by researchers at the University of North Carolina’s Center for Functional GI and Motility Disorders, studies have shown that IBS patients have a much higher likelihood of experiencing headaches and back pain than those without the condition.

Estimates about how common these symptoms are within people with IBS are varied, but one study which looked into five separate chronic conditions found that people with IBS are 2.6 times more likely to have back pain than those without it.

And the same is true for headaches and migraines. A 2020 study of 2,885 people found that people with IBS have a 44% chance of co-existing headaches compared to people without IBS having just a 23% chance. And in 2006, a big study into the link between migraines and IBS found that people with the condition are 1.5 times more likely to get migraines than those who don’t have IBS. 

Why is this? Again, it’s complicated due to a lack of research. Some experts believe it’s a form of referred pain, where the nerves from the gut and surrounding areas interact with those in the back and spine.

Some theories suggest that people with IBS have more sensitive nerves, and this could mean they’re more likely to experience pain across the body. Low serotonin levels have also been linked to heightened somatic awareness or sensitivity, which can increase the perception of pain. 

The review of studies by the University of North Carolina’s Center for Functional GI and Motility Disorders also found heart palpitations, or a racing heart, to be more common in patients with IBS than those without it.

While there are several theories as to why IBS can lead to heart palpitations, it’s worthwhile booking in an appointment with your GP to discuss your symptoms if they’re becoming a frequent occurrence. Indeed, the NHS advises people to ask for an urgent appointment if you have shortness of breath and pale skin alongside your palpitations, as this can be a sign of something more serious.

One possible explanation of why IBS can cause these heart rhythm changes is to do with its impact on nutrient absorption, Wilkinson says. “IBS affects your body’s ability to absorb nutrients such as magnesium and B vitamins, which help the heart to function properly,” she explains. The same can also be said for iron absorption which, when impaired, can lead to anaemia – which can also cause heart palpitations.

Anxiety and depression – which up to a third of people with IBS experience – are also known triggers for palpitations or feeling like your heart is racing. 

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