FODMAPs are certain types of carbohydrates that are not absorbed in the small intestine and are instead passed into the colon. Although they are poorly absorbed by everyone, only some people get IBS symptoms when bloating, flatulence, abdominal pain and constipation occur as the natural bacteria in the colon digest the food.
These FODMAPs (Fermentable oligosaccharides, Disaccharides, Monosaccharides and polyols) tend to be found in processed foods, artificial sweeteners, wheat products, some vegetables, fruit and pulses and some dairy foods. For example, fructose (a monosaccharide) is the main type of sugar found in fruit juice, fruit and honey; lactose (a disaccharide) is the main type of sugar found in dairy products; and types of sugars called oligosaccharides are found in foods such as cereals, bread, pasta, biscuits and cakes.
How the low-FODMAP diet works
With the help of a dietitian, over a period of eight weeks, FODMAPs are virtually eliminated. If your gut is going to respond to a low-FODMAP diet, this is the period during which IBS symptoms should lessen dramatically or disappear. You then reintroduce FODMAPs one by one – each over a period of three days. From this you can establish those that trigger IBS symptoms and those your body is able to tolerate. It may be that you can tolerate certain amounts of a certain FODMAP, which is useful to know if you’re going out for dinner, or to a friend’s house.
‘One of my clients, for example, now knows she can tolerate some gluten-containing foods occasionally without aggravating her IBS symptoms,’ says registered dietitian and IBS specialist Jennifer Low. ‘This has been useful as her husband’s family eat lots of pasta. But she also knows if she has a wheat-based cereal for breakfast, a sandwich at lunch and pasta for dinner she gets a very painful tummy.’
If you think a low-FODMAP diet may relieve your symptoms, look for a registered dietitian in your area (ask your GP to refer you or visit freelancedietitians.org), who will be able to guide you through the elimination and reintroduction process. It’s very important not to try it without guidance. ‘Many foods contain FODMAPs and you could seriously compromise your health if you try to eliminate these foods without the help of a health practitioner,’ says Jennifer.
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Which foods contain FODMAPS?
Flours and grainsBarley
CerealsWheat-based and mixed-grain breakfast cereals
Pasta and noodlesEgg noodles
Breads, biscuits and cakesAll biscuits
Muffins and pastries containing wheat and rye
Ready-made sourdough breads
Dairy foods and alternativesMilk
Soft cheeses (in large quantities)
Meat, fish and eggsSausages and other processed meats (check for onion and dehydrated vegetable powders)
Nuts and seedsPistachios
Spreads, condiments and flavouringsHoney
Gravies (containing onion)
Relishes and sauces
DrinksFruit juices made with FODMAP fruits (see above)
Fats and oilsDairy spreads and margarine (in large quantities)
This list should be used only under the guidance of a registered dietitian specialising in IBS management.
*These contain the oligosaccharides GOS and fructans, but in small amounts as part of a recipe do not cause IBS symptoms in most people. You should assess your tolerance under the supervision of a registered dietitian.