What are FODMAPs, are they something I need to avoid? Or are they something only people who have Irritable Bowel Syndrome (IBS) need to know about?
FODMAP is an abbreviation for fermentable oligosaccharides, disaccharides, monosaccharides and polyols (1). These are a group of short chain carbohydrates that are poorly digested and absorbed in some people, and ferment in the large bowel causing gastrointestinal symptoms such as bloating, pain, diarrhoea, constipation,nausea and vomiting.
Oligosaccharides = Fructans and Galacto-Oligosaccharides
Disaccharides = Lactose
Monosaccharides = Excess fructose
Polyols = Sugar alcohols (sorbitol,mannitol, xylitol). Isomalt and polydextrose act in a similar way.
Most fruits, vegetables, grains, beans, pulses, legumes and cereals contain varied amounts and types of carbohydrate, that when digested break down into smaller chain carbohydrates and fibre. FODMAPs are not digested in the small colon, and move to the large colon where the majority of gut bacteria reside. The gut bacteria in the large bowel ferment the small chain carbohydrates and fibre. The fermentation processes draws water into the large bowel, and produces short chain fatty acids and gas. The gas produced is either passed through flatus or dissolved into the blood, and then expired through the breath as CO2 (1). The combination of the water drawn into the large bowel and the production of gas can cause problems for some people. Foods can be classified as a high or low FODMAP, depending on the overall FODMAP content of the serving size.
IBS is a persistent digestive problem experienced by certain people. It is important to rule out any other serious condition such as Coeliac Disease before IBS is diagnosed. IBS is multifactorial, and as well as diet, causes can include menstruation, physical activity, stress, emotional or physical trauma, antibiotics, bacterial overgrowth, and poor eating habits. IBS is usually diagnosed with the ‘Rome IV’ criteria, conducted by your GP or gastroenterologist. If it is not conclusive, you should be referred for other diagnostic tests. A low FODMAP diet has been shown to be very successful in the treatment of IBS (2, 3) as an alternative to other dietary modifications such as reducing caffeine and alcohol intake, eating regular, non-spicy/ non-fatty meals, stress relief and regular exercise (4). Restricting FODMAP intake may also help for other gastrointestinal diseases such as inflammatory bowel diseases (5, 6) and IBS in children (7).
To test your tolerance for FODMAPs it is advised that you follow a low FODMAP diet for 2 – 6 weeks until symptoms minimize or disappear. Then under the supervision of an experienced FODMAP Dietitian, a reintroduction phase is gradually undertaken with the different FODMAP groups. This process can take several weeks or months, and it is important to trial individual tolerance and FODMAP load as this varies between individuals.
A low FODMAP diet is a temporary diet and is not designed to be followed long term, as this can restrict major food groups (such as dairy) and lead to nutritional deficiencies. It is designed to reduce symptoms and then test your individual tolerance to specific FODMAP foods. Seek the help of an experienced FODMAP Dietitian or Nutritionist who has completed FODMAP training, to provide individualised guidance on the FODMAP diet.