FODMAP

FODMAPs are short chain carbohydrates that are poorly absorbed in the small intestine. They include short chain oligo-saccharide polymers of fructose (fructans) and galactooligosaccharides (GOS, stachyose, raffinose), disaccharides (lactose), monosaccharides (fructose), and sugar alcohols (polyols), such as sorbitol, mannitol, xylitol and maltitol.

The term FODMAP is an acronym, derived from "Fermentable, Oligo-, Di-, Mono-saccharides And Polyols". Although FODMAPs are naturally present in food and the human diet, FODMAP restriction has been found to improve symptom control in people with irritable bowel syndrome (IBS) and other functional gastrointestinal disorders (FGID). Prior to the formation of the FODMAP concept, diet was seldom used as first line therapy for management of IBS and other FGID.

Over many years, there have been multiple observations that ingestion of certain short-chain carbohydrates, including lactose, fructose and sorbitol, fructans and galactooligosaccharides, induced IBS-like symptoms. These studies also showed that dietary restriction of short-chain carbohydrates was associated with symptom improvement in some people with IBS.

These short-chain carbohydrates (lactose, fructose and sorbitol, fructans and GOS) behave similarly in the intestine. Firstly, being small molecules and either poorly absorbed or not absorbed at all, they drag water into the intestine via osmosis. Secondly, these molecules are readily fermented by colonic bacteria, so upon malabsorption in the small intestine they enter the large intestine where they generate gases (hydrogen, carbon dioxide and methane). The dual actions of these carbohydrates cause an expansion in volume of intestinal contents, which stretches the intestinal wall and stimulates nerves in the gut. It is this 'stretching' that triggers the sensations of pain and discomfort that are commonly experienced by IBS sufferers.

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