The low FODMAP diet, researched now for a number of years, has been shown to be effective in relieving Irritable Bowel Syndrome (IBS) symptoms such as bloating, wind, abdominal pain, constipation, diarrheoa and altered bowel habit. The diet originated in Australia and was developed by a team at Monash University in Melbourne. The low FODMAP diet is effective for about 70% of people with IBS who try it(1).
What are FODMAPs?
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols which are certain types of carbohydrates and sugars that are NOT successfully broken down and absorbed by the small intestine. These particular types of carbohydrates and sugars include lactose, fructose, fructans and galactans, in addition, sugar alcohols which are often used as sweeteners. When these molecules are poorly absorbed in the small intestine of the gut they continue along their journey arriving at the large intestine where they act as a food source to the bacteria that live there normally. Undigested FODMAP containing foods can act like a sponge drawing water into the gut and trapping it there. In addition, the combination of bacteria and FODMAP foods in the large intestine produces a LOT of gas. The result? Bloating, pain, diarrheoa and/or constipation, all classic IBS symptoms.
Professor Peter Whorwell, Gastroenterologist from the University Hospital of South Manchester says
“there is emerging evidence that a diet low in FODMAP’s seems to help reduce the symptoms of IBS. Certainly it is easy to implement and a patient should adhere to it for two to three months after which they can make a judgement about whether it has helped or not. If it helps they should continue and if it doesn’t then they should abandon the idea as it does not work for everybody”.
It’s not obvious which foods contain FODMAPs and which don’t and so guidance is needed from a Dietician or Nutritional Therapist to determine which foods can be eaten and which need to be avoided. The IBS Diet Programme can help IBS sufferers find out which foods they can tolerate, and which foods they need to avoid to reduce their symptoms. For example, some people will react more to fructose and fructan containing foods, others to those containing galactans or lactose and so not all types of FODMAP foods may need to be removed from the diet long term.
(1) Gibson P and Shepherd S, 2010: Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. J Gastroenterol Hepatol 25, 252-8
By Dr Gill Hart