I have been on a modified low FODMAP diet for years now and am constantly surprised by how many high FODMAP ingredients are lurking in foods. My top two sneaky high FODMAP fibers are chicory root (fiber or extract) and inulin. So what exactly are these? Inulin is a naturally occurring polysaccharides produced in many types of plants, many of which are high FODMAP. It can also be industrially isolated from the root of a chicory plant. Dried chicory root extract or fiber contains ~98% inulin. Endive and radicchio are the leaves of the chicory plant leaves which are both low FODMAP.
Inulin is a plant based fiber that we as humans do not have the digestive enzymes to break down. This fiber travels to the large intestine where it is consumed by our gut bacteria. Since inulin is fermentable it can cause excess gas and bloating. The high osmotic activity can cause fluid to be pulled into the colon often causing diarrhea . Inulin belong to a class of dietary fibers known as fructans which are high FODMAP oligosaccharides. For those with irritable bowel syndrome even small doses like 0.5 to 1 gram can cause gas, bloating, abdominal pain, and diarrhea. Most people without digestive disorders can tolerate up to 5 to 10 grams without discomfort.
Inulin and chicory root are often found in cow’s milk, coconut, and soy based yogurts, coconut and low carbohydrate ice creams, protein shakes, meal replacement shakes, high fiber bars, low carbohydrate bars, granola, cereals, artificial sweeteners, and some gluten free breads. Some other surprising places these are found is herbal teas (most of Celestial seasoning contain roasted chicory), herbal roasted coffee, digestive enzymes, and probiotics. Be sure to read the ingredient labels of all foods and supplements for chicory root, chicory extract, roasted chicory or inulin and avoid if you are intolerance to fructans. Be on the lookout for key words such as high fiber, gluten free, or contains prebiotics since these can all imply this FODMAP was added.
Why is inulin added to some foods? The soluble component of inulin means that it is water soluble which provides moisture and a creamy mouth feel to foods. It is a cheap substance to produce, adds bulk and makes foods products sound healthy by increasing the fiber content.
From a GI dietitian's perspective if you tolerate inulin, include tolerable amounts in whole food forms instead of processed foods with added chicory root or inulin. Why? Prebiotics are the fuel or food for probiotics and our gut bacteria which is important for a healthy microbiome; therefore, finding your threshold of tolerance and regular inclusion in your diet can be of great benefit.
Here are some foods that are high in natural inulin
•Jicama- this is tested low in FODMAP up to 1 cup per Monash
•Onion and onion powder
•Garlic and garlic powder
•Green or unripe bananas
Jerusalem artichokes are very high in inulin (78% inulin) and especially high in inulin and can provoke excessive gas and abdominal pain even in those without IBS.