If you are thinking of starting an elimination diet then it’s difficult to know where you should start. YorkTest test results will highlight foods that you have had an IgG reaction to in your blood, and YorkTest Nutritional Therapist’s advice is that these should be avoided. However, in addition, there is emerging evidence that a diet low in “FODMAPs” can reduce the symptoms of irritable bowel syndrome (IBS) (1). What is FODMAP? FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols which are certain types of carbohydrates and sugars that are NOT successfully broken down and absorbed by the small intestine. When these molecules are poorly absorbed in the small intestine of the gut they then continue along their journey arriving at the large intestine where they act as a food source to the bacteria that live there normally. Undigested FODMAP foods can act like a sponge drawing water into the gut and trapping it there. In addition, the combination of bacteria and FODMAP foods in the large intestine produces a LOT of gas. The result? Bloating, pain, diarrheoa and/or constipation, all classic IBS symptoms.
FODMAP carbohydrates include certain natural sugars in foods, and also certain types of fibre in foods. It’s not obvious which foods contain FODMAPs and which don’t and so Dietician or Nutritional Therapist guidance is needed. Here are some interesting examples:-
- Some fruits, for example apples, apricots, cherries and pears should be avoided, but others such as bananas, blueberries, cranberries, oranges or strawberries are fine.
- Vegetables such as beetroot, garlic, leeks and onions can be culprits, but carrots, courgettes, peppers, parsnips and tomatoes are FODMAP friendly.
- Wheat, rye and barley (in large amounts) are a big NO NO. Note that FODMAPs don’t have anything to do with gluten or coeliac disease, it’s just a coincidence that FODMAPs are contained in these gluten containing grains.
- Milk sugar (lactose) can be problematic, as can all types of legumes, for example baked beans, kidney beans and bortolotti beans, also lentils and chickpeas.
Professor Peter Whorwell, Gastroenterologist from the University Hospital of South Manchester says “there is emerging evidence that a diet low in FODMAP’s seems to help reduce the symptoms of IBS. Certainly it is easy to implement and a patient should adhere to it for two to three months after which they can make a judgement about whether it has helped or not. If it helps they should continue and if it doesn’t then they should abandon the idea as it does not work for everybody”.
There are other non-FODMAP foods that IBS sufferers may wish to try avoiding. For example foods high in fast releasing sugars such as unrefined grains, confectionary, cakes and biscuits, and insoluble fibre such as bran. Soluble fibre such as that contained in oats is usually more tolerable. Saturated fats from red meat may exacerbate symptoms and stimulants such as coffee, tea and sugary carbonated drinks.
This may all sound daunting; lots to think about before starting an elimination diet, but it’s important to remember that each IBS sufferer will have different food triggers and combining information about known IgG reactions (2) with other likely culprit foods to try and remove may help.
(1) Gibson P and Shepherd S, 2010: Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. J Gastroenterol Hepatol 25, 252-8
(2) Atkinson W, Sheldon T, Shaath N and Whorwell P, 2004: Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut 53, 1459-64
By Dr Gill Hart