For me there are few things better than the smell of fresh coffee first thing in the morning. Coffee is a well-known stimulant so whilst helping to wake up the mind, it can also wake up the digestive tract!
If you have IBS and experience diarrhea, coffee might worsen your symptoms. However, if constipation is an issue for you, a morning coffee might have a positive laxative effect and help with bowel movements. In this article, we will explore the relationship between coffee and IBS, discuss whether coffee needs to be avoided, and provide tips to help you still enjoy your coffee.
What evidence do we have that caffeine is a trigger?
Various observational studies suggest caffeine is a common IBS trigger and in one study involving 390 participants, 39% reported that their IBS symptoms were related to drinking coffee (Food-related gastrointestinal symptoms in the irritable bowel syndrome – PubMed (nih.gov)). Additionally a small study in healthy participants showed that coffee may increase gastrointestinal motility, a greater extent than water or decaffeinated coffee (Is coffee a colonic stimulant? – PubMed (nih.gov)). What is important to note is many of the studies looking at coffee are observational and therefore a “cause and effect relationship” i.e. coffee causes increased bowel movements cannot be determined. As with many aspects of IBS symptom triggers are very individual and therefore working closely with an experienced dietitian can be invaluable in helping you identify your triggers
The Food and Drug Administration (FDA) Trusted Source states consuming about 400 mg of caffeine a day shouldn’t cause symptoms in most healthy adults. This is about 3-4 cups of coffee. However this might prove too much if you suffer with IBS, anxiety and/or sleep disorders as smaller amounts can contribute to restlessness, insomnia and a rapid heartbeat in some people. Increased anxiety and poor sleep create a vicious cycle which can result in worsening of IBS symptoms.
How does coffee affect gut symptoms?
For some individuals, the impact of caffeine on their symptoms and mood can vary. The effects of caffeine are influenced by factors such as the preparation of coffee, individual differences in caffeine metabolism, and personal tolerance levels. Click here to learn more.
Caffeine typically acts as a gastrointestinal stimulant, speeding up gut peristalsis, which are the muscle contractions that move food through the digestive tract. This increased movement through the gut can lead to stomach cramping and more urgent loose stools.
Another potential reason is both caffeinated and decaffeinated coffee cause hormones including Gastrin and Cholecystokinin to be released. These hormones trigger the gastro-colic reflex, causing the colon to contract and increasing the urge to open your bowels after a coffee.
Whilst the caffeine content of coffee is thought to be one of the reasons for this, how you take your coffee i.e. what milk you use, use of coffee creamer or sweetener can also potentially contribute to gut symptoms.

Should caffeine be avoided?
Absolutely not! Alongside caffeine, there are many other nutritional compounds found in coffee including polyphenols and fibre, and therefore many reported benefits from enjoying regular coffee. Studies are showing that coffee drinkers have less heart disease than non-coffee drinkers. This is a great listen to if you need convincing further… ZOE Podcast: Is Coffee Healthy?
However, the amount of coffee you can drink depends on your genetic predisposition (how fast you metabolize caffeine), your individual tolerance, and how you prepare it i.e. with milk, cream, and sugar as these can influence how your coffee is digested.
So how can coffee continue to be part of your morning ritual without the unwanted side effects? Some ideas include:
1) Consider reducing your caffeine intake:
You do not need to quit caffeine to help IBS. However, you might want to try gradually reducing your intake and monitor how you feel. The BDA has produced an information leaflet for IBS (click here) which states “Reduce intake of caffeine-containing drinks e.g. no more than two mugs (three cups) a day. However, there is an upper limit to caffeine consumption, and the recommended intake of caffeine for adults is no more than 400mg per day, which is about 4 cups of standard coffee.
2) Consider decaffeinated alternative
Decaffeinated coffee has 97% less caffeine than caffeinated coffee and can be a great option for people who love the smell and taste of coffee but wish to avoid the side effects of caffeine, whilst also benefitting from the polyphenol (powerful antioxidants) content of coffee.
3) Avoid drinking coffee on an empty stomach
Drinking coffee on an empty stomach can potentially mean your body absorbs the coffee (and caffeine) quicker as there is nothing else in your stomach. Simply eating something with your cuppa could reduce the absorption rate of caffeine and reduce symptoms. Great examples include toast and peanut butter, Greek yogurt with cereals and fruit, or good old-fashioned oats.
The bottom line?
For many enjoying a cup of coffee is not harmful and there are proven health benefits linked to drinking coffee. However if you are sensitive to coffee/caffeine you might benefit from limiting your caffeine intake or enjoying a nibble alongside your coffee. Equally whilst the above might show a compelling story for caffeine contributing to IBS symptoms there are many other causes of IBS and if you are keen to discover what your personal triggers are then make yourself a cuppa and click here for a free discovery call.