IBD and Diet -


By Dr Karen Munday

Clinicians and dieticians are often faced with a difficult problem when trying to advise individuals with IBD about which foods they should and shouldn’t be eating – there is no one diet that suits all. Some can eat whatever they like without ever incurring a flare-up of the symptoms. Others can eat some foods on a good day, but on other days, have to avoid them. Others have identified foods that they definitely cannot eat, ever.

One method for determining which category a newly diagnosed individual falls into is simply through trial and error. If a person eats something then suffers diarrhoea, bloating, stomach cramps, then they should avoid that food. However, even the simplest meal will contain a number of different ingredients and food components which could be the cause of the sensitivity. A basic pasta dish, for example, may consist of wheat-based pasta (gluten), tomato sauce, meat (fat intolerance), some vegetables and herbs. Any of these ingredients could trigger the symptoms, and the individual may opt to avoid all of them to prevent a further problems.

A more precise way of determining which foods cause problems is through following an elimination diet or an oral challenge. An elimination diet involves removing all suspect foods from the diet for a period of 1 to 3 weeks. Small portions of specific foods are then gradually reintroduced until a reaction is seen. Individual foods that are not tolerated can thus be identified and avoided. Although, in theory, this might sound quite simple, in practice it can be very difficult and tedious to perform, especially if the individual does not already have a clear idea of which foods may worsen their disease symptoms. Individuals with IBD could have nutritional deficiencies as a result of their inability to digest or tolerate foods, and one of the key features of them maintaining their health is through eating a balanced diet. Performing and elimination diet could exacerbate this problem. Also, problem foods cannot be easily identified if the individual is taking medication, therefore for maximum chance of success, all medication would need to be stopped before attempting an elimination diet. For many individuals with IBD, this is not an option.

There are numerous ways of performing allergy tests, including skin tests. Skin tests can accurately determine allergies to the following foods; milk, eggs, peanut, wheat, soy and fish and shellfish. Reactions to other foods, such as vegetables, cannot be so easily identified through this method. Alternative approaches are also available, but are often scientifically unproven. With these unproven methods, there is the potential for the practitioner to be over-cautious about the range of foods to be avoided, resulting in an unnecessary bland and potentially unbalanced diet.

The majority of individuals with IBD suffer from food intolerances not food allergies which are much rarer in adults. It has been estimated that in America, less than 2% of the adult population suffer from a food allergy1, which is significantly lower than the number that have food sensitivities.

So, what advice can be offered? As part of a nation-wide study on Crohn’s Disease being carried out by Nutrigenomics New Zealand2 approximately 800 individuals with IBD were questioned about their dietary tolerances and intolerances. The results have been entered into a database and will be analysed in conjunction with information about a number of IBD-related genes.

Some points did come up through the survey which could be passed on as general advice for individuals with IBD.

With fruit and vegetables, some found that fruits and vegetables were better tolerated if the skins and seeds were removed; others if they were eaten cooked as opposed to raw. Others found they could tolerate fruit juice but not whole fruits, and some had to avoid all acid fruits, such as the citrus fruits and acidic tomatoes. Although few claimed that organic fruits or vegetables helped, many people ate vegetables and fruits from their gardens. Other tried to obtain their fresh produce from Farmers markets.

Many people claimed that fatty meats caused problems and some were unable to tolerate processed meats. A diet high in animal fats is not advisable for anyone, therefore always try and select low-fat cuts of meats. If you find the low fat cuts too expensive, go for less quantity rather than less quality.

If you want to cook with mince (which is traditionally very fatty) ask your butcher to mince some lean meat for you, or look for chicken mince, which has a lower fat content.

In processed meats, there are usually a number of ‘hidden’ ingredients, so it is worth checking the labels (or asking for a list of the ingredients if you are buying from a Deli) before you buy.

It may not necessarily be the fat content in the meat that causes problems. The way that the animals are reared may also affect the ability to tolerate the meat. For example, one of the study participants, who is soy-intolerant, found that she was also intolerant to chicken from chickens fed on a soy-based diet. Information about animal handling and feeds can be obtained from the distributors, or by chatting to your local butcher if you have one.

A number of people had problems with gluten intolerance. There is a good range of gluten-free products available in New Zealand, although they can be considerably more expensive than their mass-produced gluten containing counter-parts. Check out the Orgran range (www.Orgran.com), which comes from Australia and is gluten-free, wheat-free, dairy-free, egg-free, yeast-free, GMO-free and vegan. These, and similar products can usually be found at health stores and organic shops. Again, if these are beyond your price range, try making your own. Invest in a bread maker (pick up a second-hand one), many of which have pasta-making functions, and try out different gluten-free bakes. Some individuals with wheat-intolerance are able to tolerate rye or spelt, both of which can make excellent breads. Buckwheat is also a good wheat-flour substitute, and is completely gluten free, being from the rhubarb family. Buckwheat flour makes great pastry, muffins and cakes if you need a sweet treat (but didn’t work well when I tried to make profiteroles with it!) Amaranth and quinoa also come in a flour form, and although expensive, have a high iron, calcium, folate and magnesium, plus they are a good source of protein. They can be added in place of other flours to increase the nutritional value of a meal (mix 2:1:1 with buckwheat flour for savoury pastry or pancakes).

When asked about which drinks they were able to tolerate or not, many respondents stated that sugary drinks caused problems. Too much sugar, as is the case with too much artificial sweetener, can cause diarrhoea. However, some people found ‘sports’ drinks useful for keeping their energy levels up when they were experiencing a flare-up and unable to tolerate solids. A large proportion of those questioned avoided alcohol.

The results from the Nutrigenomics New Zealand study are in the process of being analysed, so watch this space for the results, which should be available towards the end of the year.

  1. Sicherer SH. Manifestations of food allergy: Evaluation and management. American Family Physician 59:415-424, 1999. [go back]
  2. Nutrigenomics New Zealand (www.nutrigenomics.org.nz) is collaboration between AgResearch, Crop & Food Research, HortResearch and the University of Auckland and is largely funded by the Foundation for Research, Science and Technology. 
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