Caffeine and Irritable Bowel Syndrome


I often get asked the question "Is caffeine good for me?".

The answer isn't black or white.

Caffeine is a stimulant and the most widely used drug around the world. It's obviously legal here in Australia as well as many other places. It is found in coffee, tea, coke, cocoa and chocolate. Because of it's stimulant effect, caffeine can help you to stay alert, can assist with mental efficiency and can also assist athletes to get better results (less perceived exertion). If you like coffee, enjoying up to 3 cups per day is considered safe for most people.

However, there can be a few negatives of caffeine including increasing heart rate, increasing blood pressure, can be related to dehydration, poor sleep, headaches and heartburn. Excessive amounts of caffeine can strip the bones of calcium (in extreme circumstances). For people with IBS and who consume large amount of coffee, a reduction in intake may assist with reducing gastrointestinal symptoms. In a recent study, almost 40% of people with IBS identified coffee as a trigger for their symptoms. One in 4 with IBS regularly avoid coffee because of this. Other studies have found that 14-33% of people on the elimination diet whose symptoms improved, found that they had a recurrence of symptoms when coffee was reintroduced into the diet. The research suggests that caffeine may induce these gastrointestinal symptoms because of it's effect on colonic motor activity. In a study of healthy participants (without IBS) a third reported the need to use the loo after consuming a coffee. 

In saying all of this, these results were pulled mainly from observational studies, rather than randomised control trials which mean that we cannot definitively say that coffee causes IBS symptoms.

The other thing to consider is that some people may not react to the caffeine, but may react to the lactose in the milk they are adding to the coffee. Lactose is a disaccharide that is usually eliminated in the first stage of the low FODMAP diet.

As with anything in relation to diet, there is no one size fits all approach. Working with a dietitian who specialises in irritable bowel syndrome will guide you to determine your individual triggers.