Research looking at diet therapies for IBS has focused on a group of sugars, known as FODMAPs (Fermentable Oligo-saccharides, Di-saccharides, Mono-saccharides and Polyols). These sugars can be poorly absorbed in the small intestine and fermented by bacteria in the large intestine to produce gas. There is now a large body of research showing that reducing FODMAP intake improves IBS symptoms in the majority of people with IBS.
Stress is also a common trigger of IBS symptoms. If you think stress affects your IBS symptoms, psychological therapies such as gut directed hypnotherapy and cognitive behavioural therapy (CBT) may help.
Some people suspect other food components trigger their IBS symptoms, such as fatty food, spicy food and caffeine. Although there is not strong evidence to support this, working with a dietitian can help you to identify whether other food components affect your IBS symptoms.
The process of digestion
Our small intestine helps to break down and absorb nutrients from foods. Our large intestine helps to absorb water and prepare undigested food for removal from the body (as faeces/poo). As undigested food passes through the large intestine, it is fermented by gut bacteria, and gas is produced as a result.