What are FODMAPs?
FODMAPs are a collection of molecules, more specifically short chain carbohydrates and sugar alcohols, found in foods naturally or as food additives. FODMAPs include fructose (when in excess of glucose), fructans, galacto-oligosaccharides (GOS), lactose and polyols (eg. sorbitol and mannitol). A detailed description of each of these, including the foods they are found in, is provided below.
A diet low in FODMAPs (“a Low FODMAP Diet”) is scientifically proven1, and is now used internationally, as the most effective dietary therapy for Irritable Bowel Syndrome (IBS) and symptoms of an irritable bowel. Such symptoms include excessive wind (flatus), abdominal pain, bloating and distension, nausea and changes in bowel habits (diarrhoea and/or constipation). A Low FODMAP Diet has also been proven, with solid scientific research2, to reduce symptoms of fatigue, lethargy and poor concentration.
FODMAP is an acronym that stands for:
- Fermentable – meaning they are broken down (fermented) by bacteria in the large bowel
- Oligosaccharides – “oligo” means “few” and “saccharide” means sugar. These molecules are made up of individual sugars joined together in a chain
- Disaccharides – “di” means two. This is a double sugar molecule
- Monosaccharides – “mono” means single. This is a single sugar molecule
- Polyols – these are sugar alcohols (however, they don’t lead to intoxication!)
How do FODMAPs trigger symptoms of IBS?
When consumed in foods and/or drinks, FODMAPs can be poorly absorbed in the small intestine and pass through to the large intestine, where two major events happen:
- The FODMAPs are readily fermented by bacteria in the large bowel, contributing to the production of gas.
- The FODMAPs are also highly osmotic, meaning that they attract water into the large bowel, which can alter how quickly the bowels move.
These two processes can then trigger symptoms including excess wind, abdominal bloating and distension, abdominal pain, constipation or diarrhoea, or a combination of both.
Information about each FODMAP, and examples of foods that contain FODMAPs, are listed in the table below:
An estimated 35% of the Australian population have intolerances to one or more of the above FODMAPs3. However, not all FODMAPs will be symptom triggers for all patients. By controlling and managing the consumption of foods that contain the FODMAPs triggering their symptoms, individuals can significantly reduce or even eliminate their IBS-type symptoms.
The Low FODMAP Diet
The Low FODMAP Diet is proven to be an effective dietary treatment for the vast majority of people suffering from IBS and IBS-type symptoms. People who suspect they have irritable bowel syndrome should firstly speak to their doctor about their symptoms. It is recommended that all people with IBS-like symptoms should be investigated for coeliac disease (gluten must still be consumed in the diet), and any other conditions the doctor feels is relevant to the individual. If irritable bowel syndrome is confirmed, then the low FODMAP diet is recommended for dietary management of symptoms.
There are 2 phases to implementing the Low FODMAP Diet:
- Initially, an 8-week diet trial reducing the intake of foods high in FODMAPs in people with IBS-type symptoms is undertaken. It is recommended that such people commence the diet under the advice of a dietitian, preferably a specialist in gastrointestinal nutrition (see daa.asn.au). Dietitians will generally advise the strict removal of foods that are high in FODMAPs during this phase. Dietitians are trained to provide expert nutritional advice, so will also suggest alternative foods to those that are restricted (focusing on what CAN be eaten), to ensure nutritional adequacy.
- After completing 8 weeks on the first phase of FODMAP dietary restriction, it is recommended to return to the specialist dietitian for a review to assess how well symptoms have improved in this phase. If all is going well, the dietitian will then work with the individual on the Low FODMAP Diet to plan the next steps – ie. work out the TYPE and AMOUNT of FODMAPs that can be tolerated before experiencing symptoms. It is an important step to determine how well a person can tolerate the reintroduction of FODMAPs. As well as seeking to minimise symptoms, it is a goal of the dietitian to ensure that the person obtains maximum variety in their diet. Additionally, reintroduction of FODMAPs to a level that is comfortably tolerated will enable the individual to benefit from the prebiotic effects of FODMAPs.
The most common outcome of this 2-stage process is that people with IBS-type symptoms will experience minimised symptoms, while tolerating increased variety of foods in an eating plan that is individualised.
There is an ever-growing number of scientific research studies from around the world supporting the fact that reducing FODMAPs in the diet assists in managing the symptoms of IBS4. This is not a fad diet – it is supported by scientific evidence and its use is increasing internationally. . . For example, in a scientific study performed in the UK, the Low FODMAP Diet was proven to be much more effective in relieving symptoms (76% of participants achieved IBS symptom control) than the diet formed by the UK’s National Institute for Health and Clinical Excellence (NICE) (where 54% of participants achieved IBS symptom control).
For further information:
- Refer to our Frequently Asked Questions (FAQ)
- Consult an Accredited Practising Dietitian :
- Contact the Dietitians Association of Australia (daa.asn.au)
- Contact Dietitian Associations in other countries
1 See the following research papers, amongst others:
- Shepherd SJ, Parker FJ, Muir JG and Gibson, PR Dietary triggers of abdominal symptoms in patients with irritable bowel syndrome- randomised placebo-controlled evidence Clin. Gastroenterol. Hepatol. 2008;6(7):765-771 http://www.sciencedirect.com/science/article/pii/S1542356508001511
- Halmos, EP, Power VA, Shepherd SJ, et al. A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome Gastroenterology 2014;146(1)67-75
2 See the following research papers:
- Ong DK, Mitchell SB, Barrett JS, Shepherd SJ, Irving PI, Biesiekierski JR, Smith S, Gibson PR, Muir JG. Manipulation of dietary short chain carbohydrates alters the pattern of hydrogen and methane gas production and genesis of symptoms in patients with irritable bowel syndrome. J Gastroenterol. Hepatol. 2010 Aug ;25(8):1366-73
3 Barrett JS, Irving PM, Gearry R, Shepherd SJ, Gibson PR Comparison of the prevalence of fructose and lactose malabsorption across chronic intestinal disorders Aliment. Pharmacol. Therapeutics 2009;30(2):165-74
4 See the following research papers:
- Shepherd SJ, MCE Lomer and Gibson PR Short-Chain Carbohydrates and Functional Gastrointestinal Disorders Am. J. Gastroenterol. 2013;108:707-717
- Gibson PR and Shepherd SJ Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach J. Gastroenterol. Hepatol. 2010; 25:252–258
- Gibson PR and Shepherd SJ Food Choice as a Key Management Strategy for Functional Gastrointestinal Symptoms Am. J. Gastroenterol. 2012; 107:657–666
- Staudacher HM , Lomer MCE , Anderson JL et al. Fermentable carbohydrate restriction impacts on luminal bifi dobacteria and gastrointestinal symptoms in a randomized controlled trial of patients with irritable bowel syndrome . J Nutr 2012 ; 142 : 1510 – 18 .