This blog post is written by nutrition student volunteer Mackenzie Michalczuk and edited by Lauren Renlund. There tends to be a lot of confusion about the difference between gluten and FODMAPs. In this post, Mackenzie explains what is gluten, why gluten is not a type of FODMAP and if wheat is allowed on the low FODMAP diet. This blog post is directed at individuals with Irritable Bowel Syndrome (IBS).
Do You Need to Be Gluten Free on the Low FODMAP Diet?
The simple answer is no, gluten is not a FODMAP and is not restricted on the low FODMAP diet. You only need to avoid all sources of gluten if you are celiac, have a diagnosed gluten sensitivity and/or have been specifically told by your healthcare professional to completely avoid gluten.
What is Gluten?
Gluten is a protein found in certain grains: wheat, barley, rye and triticale (a cross between wheat and rye). 1 These grains are used to make many common ingredients – click here for a Canadian list of gluten-containing foods and ingredients.
Gluten is not a type of carbohydrate, FODMAP or fructan.
What are Fructans?
Fructans are a type of highly fermentable carbohydrate and one of the five types of FODMAPs. High-quality research studies have shown that eating FODMAPs can trigger IBS symptoms and a low FODMAP diet can help manage IBS symptoms – for more information about the low FODMAP diet, click here.
Wheat, barley and rye contain varying amounts of fructans, in addition to gluten.
Summary: Gluten is a type of protein. Fructans are a type of carbohydrate. Both gluten and fructans are found in wheat, barley and rye.
What Can I Eat on the Low FODMAP Diet?
During the first phase of the low FODMAP diet, high amounts of FODMAPs such as fructans are avoided. Foods that are low in FODMAPs are allowed.
Small amounts of certain wheat products are low FODMAP.2 It is okay to include these low FODMAP wheat products in your diet as long as you monitor the portion sizes.2 You can learn the FODMAP content of many different wheat products in the Monash University Low FODMAP Diet App.3 Here is the FODMAP content of some common wheat products:
- One small slice of white bread has low amounts of fructans.3 However, a larger portion of two slices of white bread contains high amounts of fructans.3
- Wholegrain bread has more fructans than white bread; one slice of wholegrain bread has moderate amounts of fructans.3
- Certain types of sourdough bread are low FODMAP – click here for a guide to finding a low FODMAP sourdough bread.
- Half a cup of cooked white wheat pasta is low FODMAP (approximately 75 grams).3
- Five saltine crackers are low FODMAP.3
Barley and rye contain higher amounts of fructans than wheat and need to be completely avoided during the first phase of the low FODMAP diet.2
Please note that if you have been diagnosed with celiac disease you must avoid all sources of gluten, including low FODMAP wheat products.
Why Are Gluten Free Foods Recommended on the Low FODMAP Diet?
Gluten-free foods are sometimes recommended because they are often low in fructans.2 Many gluten-free flours are also low in FODMAPs (including rice, quinoa, maize/corn, potato, tapioca, teff, sorghum, millet and arrowroot). However, a gluten-free label does not guarantee a food is low FODMAP. Unfortunately, there are also many gluten-free ingredients that are high FODMAP.
It’s important to always check the ingredients list for any high FODMAP ingredients, such as inulin/chicory root extract. Click here for more a great blog post on how to determine whether a gluten-free food is low FODMAP.
Gluten-free options can come in handy when ordering food at a restaurant. Many restaurants do not know what a FODMAP is, but gluten-free options are now very common. Before ordering a gluten-free meal, inquire about all of the ingredients in the dish.
Gluten Sensitivity Might Actually be Fructan Sensitivity
Many individuals with digestive issues suspect they may be sensitive to gluten in food. However, new research has found that it is more likely that it is the FODMAPs in food triggering the digestive symptoms.
In a study conducted by Biesiekierski et al., (2013) a gluten-free diet had no effect on gut symptoms in patients. In comparison, the low FODMAP diet was able to reduce gut symptoms.4
Additionally, Skodje et al. (2018) conducted research on participants with IBS and found that they experienced significantly more symptoms after eating muesli bars with fructans, compared to bars with gluten or placebo bars (i.e., no gluten or fructans). These results indicate it was the fructans, rather than the gluten, that triggered digestive symptoms.5
More research is needed to fully understand gluten sensitivity and fructan sensitivity. If you are experiencing digestive issues, please speak to your physician for guidance. Once you have received a diagnosis, a registered dietitian can help determine the best dietary options for managing symptoms.
If you are looking for more information on celiac disease and/or gluten sensitivity, I recommend the book “Gluten-Free: the Definitive Resource Guide” by Shelley Case, RD.
References
- Canadian Celiac Association (2018). Getting Started on the Gluten-Free Diet. Retrieved from: https://www.celiac.ca/living-gluten-free/newly-diagnosed/
- Monash University (August 10, 2015) University Gluten and the low FODMAP diet. Retrieved from: https://www.monashfodmap.com/blog/avoiding-wheat-how-strict-on-low-fodmap/
- Monash App. Food Guide & Information Section. The Monash University Low FODMAP Diet App. 2016: Version 2.0(314). Retrieved from: http://www.med.monash.edu/cecs/gastro/fodmap/iphone-app.html
- Biesiekierski JR, Peters SL, Newnham ED, Rosella O, Muir JG, Gibson PR. (August, 2013). No effects of gluten in patients with self-reported non-celiac gluten sensitivity following dietary reduction of fermentable, poorly-absorbed, shortchain carbohydrates. Gastroenterology;145(2):320-8
- Skodje et al., (February, 2018). Fructans rather than gluten, induces symptoms in patients with self-reported non-celiac gluten sensitivity. Gastroenterology;154(3). doi:10.1053/j.gastro.2018.01.040
Understanding the purpose of gluten-free products during the Low FODMAP Diet is such an important part of a patient’s overall success. It helps patients properly identify the ingredients they’re avoiding (like fructans instead of gluten) and gives patients access to products they may have avoided otherwise (like possibly cross-contaminated oats). Great article on a much-needed topic!