O Oligo-saccharides (Fructans & galacto-oligosaccarides)
D Di-saccharides (lactose)
M Mono-saccharides (Fructose)
P Polyols (sugar alcohols)
Most FODMAP's are poorly absorbed by everyone, but they do not cause IBS symptoms in everyone. They only need to be restricted is they are causing or worsening IBS symptoms. To find this out all FODMAP's need to be removed from the diet for 1 month and then re introduced to see if some or all the FODMAP's are causing symptoms for an individual. Some people are more sensitive to some FODMAP's but can manage others without symptoms.
Which foods contain FODMAPS?
Fermentable. This just means that these foods are poorly absorbed so stay in the digestive system and are "fermented" by bacteria producing gas, bloating, distention and constipation. They also act to pull a lot of fluid into the digestive system often leading to diarrhoea.
Oligo-saccharides. Fructans and glacto-oligosaccharides are found in wheat, rye and barley. Various fruits and vegetables, pulses and as added ingredients sometimes termed as "Prebiotics" (not to be confused with "Probiotics" which can be eaten on a Low FODMAP diet)
Di-saccharides are found in lactose which is a milk sugar. The major sources are milk (all animal milks cow, goat, sheep etc) and yoghurt. Soft cheeses contain some lactose but hard cheeses such as cheddar are extremely low in lactose and so can be eaten on a Low FODMAP diet.
Mono-saccharides. Fructose is a fruit sugar so is found in fruit as well as honey and agave nectar. It can also be added to foods to sweeten them. Fructose is poorly absorbed but another sugar glucose is very easily absorbed. Fructose can "piggy back" onto glucose and be more easily absorbed. It can only do this if glucose is present. This is why fruits where glucose and fructose are present in equal amounts or where there is more glucose than fructose do not cause symptoms. It is also why table sugar (sucrose) does not cause symptoms as it is made up of equal parts of fructose and glucose.
Polyols These are sugar alcohols found in various fruits and vegetables, sugar-free chewing gum and sugar free mints.
A well balanced, easy to manage, least restrictive to control symptoms Low FODMAP dietary treatment consists of;
Removal of FODMAP's from the diet
Re- Introduction to test tolerance
If you would like to read more on the diet "The Complete Low-FODMAP Diet" by Sue Shepherd & Peter Gibson is an excellent book