IBS - a new dietary approach (that works!)

IBS is an incredibly common condition affecting 1 in 5 people. It's severity and symptoms can range from mild bloating and constipation to debilitating pain and diarrhoea. A diagnosis of IBS is usually made by your GP or gastroenterologist after other causes have been ruled out e.g. Coeliac disease, Crohn's disease, ulcerative colitis. Until recently, the standard advice from the NHS has been to cut down on caffeine, alcohol, fruit juice, stop smoking, increase fibre and reduce stress.

Unfortunately, for many, this advice only has limited success. In fact, increasing fibre can often make symptoms worse.

New research from Monash University, Australia and King's College, London shows that the gas, bloating, diarrhoea/constipation are caused by certain fermentable sugars and fibres. Gut bacteria live in the large intestine (colon), and they feed on these fermentable foods producing gas and drawing in water. People with IBS may have an imbalance of the gut bacteria causing excessive gas and diarrhoea to be produced, and may also have guts that are more sensitive to the gas production. This sensitivity is felt as pain.

The scientific term for these fermentable foods is 'FODMAPs' which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. Quite a mouthful! Surprisingly, foods that are generally thought to be very healthy and good for the bowels can be high in these FODMAPs.

Common high FODMAP foods include apples, pears, garlic, onions, wheat, honey, beans, lentils, soy and lactose (found in milk, yogurt and ice-cream). Not everyone with IBS reacts badly to all of these foods. 

What is a low FODMAP diet?

The aim of a low FODMAP diet is to establish which of these foods are causing the IBS symptoms. For approximately four weeks high FODMAP foods are eliminated from the diet until symptoms resolve. Some people see significant improvement within days, for others it can take a few weeks. The next stage of the diet is to systematically reintroduce the high FODMAP foods to discover which ones cause the symptoms. This allows particular trigger foods to be identified.

Does it help IBS?

Scientific studies show that the low FODMAP approach is effective in 3 out of 4 people, which is a significant improvement on previous treatments. It is so successful that gastroenterologists now recommend the diet for their IBS patients. It is routinely used in major hospitals such as Guy's & St Thomas' in London.

Just remember, if you have IBS it does not mean that you need to eliminate all high FODMAP foods forever. The goal is to identify the ones causing you problems, so that you can eat as wide a variety of foods as possible while minimising IBS symptoms. Life changing for many!

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

Share this article with a friend
Bangor, Down, BT20 5JN
Written by Sarah Danaher, BSc MSc RD mBDA
Bangor, Down, BT20 5JN

22 years of dietetic experience in the NHS (Ulster Hospital, Guy's & St Thomas', Chelsea & Westminster, St George's London), private practice, elite and amateur sport and lecturing. I also produce written dietetic guides for people who are unable to afford private dietetic consultation. Thes...

Show comments

Find a nutritionist dealing with Irritable bowel syndrome (IBS)

All nutrition professionals are verified

All nutrition professionals are verified