What is IBS?
Irritable bowel syndrome (IBS) is a multifactorial disorder that involves altered motility,
brain-gut interaction, intestinal microbiota, gut permeability, visceral sensation, and gut immune
activation. IBS affects 7% to 16% of individuals in the United States. IBS causes recurrent
abdominal pain and altered bowel habits commonly resulting in gas, bloating, abdominal
distension, and urgency. IBS is commonly categorized into four different subtypes: IBS with
diarrhea (IBS-D), IBS with constipation (IBS-C), IBS with mixed constipation and diarrhea
(IBS-M) and IBS without a significant pattern of abnormal stool (IBS-U). 1
What is low FODMAP?
Living with IBS can lead to decreased quality of life, social isolation, and work
performance interference. The low fermentable, oligosaccharide-, disaccharide-,
monosaccharide-, and polyol (FODMAP) diet has been the predominant diet treatment for IBS. 2
FODMAPs are short chain carbohydrates that are not properly absorbed in the gut which can
lead to gastrointestinal symptoms like cramping, bloating, and diarrhea. 3 FODMAPs are a
naturally forming sugar that can be found in a wide variety of foods. 4 The reducing the amount of FODMAPs in the diet has shown to improve symptoms of IBS. 3 The low FODMAP diet consists of three phases: elimination phase, challenge phase, and reintroduction phase. In the elimination phase,
high FODMAP foods are reduced from the diet for 2-6 weeks. In the challenge phase,
individuals identify triggers by incorporating one FODMAP group back into their diet at a time, testing serving sizes of each FODMAP group to identify tolerance levels. Lastly, in the reintroduction phase, individuals reintroduce the FODMAP foods that were not identified as triggers back into their diet.
What are Fructans?
In the elimination phase of the low FODMAP diet, individuals commonly find difficulty
eliminating fructans. A fructan is a molecule that consists of a chain of fructose sugar molecules
joined together with a glucose molecule at the end. Fructan is part of the oligosaccharide- group
in FODMAPs. When challenging fructans, the challenge groups are broken into 4 categories, this is because the portion sizes found in food greatly varies, and is found in a variety of food sources.
Fructan Grains: This category includes any typical bread products, pastries, and pizza dough. When identifying high fructan grains, one should look for wheat, barley, rye, and spelt in ingredient lists.
Fructan Fruits and Vegetables:
Onion
Garlic
Identifying a Fructan Intolerance:
A low FODMAP diet can help determine if individuals are having an intolerance to
fructan. As mentioned before, the low FODMAP diet eliminates, challenges and reintroduces
FODMAP foods in order to determine which foods are triggering. Due to the fructan group
covering a wide variety of foods, separating this group into subgroups can be beneficial.
As you challenge each fructan group, it is important to identify which foods you can and cannot tolerate. Individuals may find that some high fructan foods do trigger their symptoms (gas, bloating,
diarrhea, constipation, abdominal pain) while others do not. Keeping a journal or food log can
aid in identifying these foods and the serving sizes tolerated. And working with a dietitian who specializes in the FODMAP diet can help you identify your tolerance levels. Once the challenging phase is completed, individuals can slowly reintroduce the foods that do not trigger their symptoms back into their diet. 5
High Fructan Foods
*note that FODMAP levels of foods are continuously tested and serving sizes may change. This is not a full comprehensive list of fructan containing foods.
Limit the below foods to the listed portion size. Each serving size listed is the serving size that is considered low FODMAP. Anything above that is considered to have a high amount of fructans.
GRAINS | VEGETABLES | FRUITS | MILK ALTERNATIVE | NUTS/BEANS/TOFU |
Wheat Bran, uncooked 1/2 TBSP | Asparagus, 1 spear | Apricot, dried, 0 | Vegan Cheese, cheddar, coconut oil based, 2 slices | Baked Beans, 1 Tbsp |
English Muffin, 1 | Beets, 2 thin slices | Banana, ripe, 1/3 medium | Vegan cheese, soy based, 2 slices | Navy Beans, dried, 1/4 cup |
Rye Bread, 0 | Green bell pepper, 1/2 cup | Cranberries, dried, 1 Tbsp | Cream cheese, garlic and herb, 0.7 oz | Black Beans, canned, 1/4 cup |
Wheat bread, 0 | Orange Bell Pepper 1/4 cup | Cranberries, raw, 1/2 cup | Condensed milk, coconut, 2 Tbsp | Beans, Cannellini, canned, 1/3 cup |
Cornflakes, 1/2 cup | Brussel Sprouts, 1.87 oz | Cantaloupe, 3/4 cup | Coconut milk, inulin, 0 | Lima Bean, dried, 1/4 cup |
Couscous, 0 | Red Cabbage, 3/4 cup | Dates, Medjool, 1 | Oat milk, 6 Tbsp | Beans, Pinto, canned, 2 Tbsp |
Barley, 0 | Savoy Cabbage, 1/2 cup | Figs, dried, 0 | Beans, Kidney, canned, 3 oz | |
Amaranth Flour, 0 | White Daikon, 1/2 cup | Goji Berries, 3 tsp | Cashew, 0 | |
Barley Flour, 0 | Poblano Pepper, 1 medium | Grapefruit, 2.8 oz | Pistachio, 15 nuts | |
Coconut Flour, 0 | Red Chili Pepper, 1 medium | Honeydew melon, 1/2 cup | Split Peas, 0 | |
Einkhorn Flour, 0 | Canned Corn, 1 cup | Passion Fruit, 2 medium | Tofu, silken, 1/4 cup | |
Wheat Flour, 0 | Edamame, shelled, frozen 1/2 cup | White Peach, 2 Tbsp | Tofu, firm 6 oz | |
Bulgur, 2/5 cup | Jicama, 1/2 cup | Pear, green 0.2 oz | ||
Farro, 1/3 cup cooked | Leek (bulb only), 1 Tbsp | Pineapple, raw 1 cup, dried (0) | ||
Freekeh, 0 | Okra, 7 Pods | Pomegranate Seeds, 1/4 cup | ||
Wheat Pasta, 1/2 cup cooked | Onion, 0 | Prune, dried, 0 | ||
Semolina, 0 | Squash, Pumpkin, 1/3 cup | Raisin, 1 Tbsp | ||
Wild Rice, 1 cup cooked | Squash, spaghetti, 1/2 cup cooked | Watermelon, 2 Tbsp | ||
Wheat Tortilla, 1 small | Zucchini, 1/2 cup |
While following a low FODMAP diet, it is important to ensure you are still
getting the nutrients your body needs. Working with a dietitian will help you to safely and
effectively navigate this process.
References
1. Academy of Nutrition and Dietetics.Nutrition Care Manual. [Irritable Bowel Syndrome].
v3=275335&ncm_toc_id=275335&ncm_heading=Nutrition%2520Care]. Accessed
[January 30, 2024].
2. Manning LP, Yao CK, Biesiekierski JR. Therapy of IBS: Is a low Fodmap Diet the
answer? Frontiers in Psychiatry. 2020;11. doi:10.3389/fpsyt.2020.00865
3. Syed K, Iswara K. Low-FODMAP Diet. [Updated 2023 Sep 4]. In: StatPearls [Internet].
Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:
4. Cleveland Clinic. Could you have a fructan intolerance? Cleveland Clinic. January 4,
2024. Accessed January 30, 2024. https://health.clevelandclinic.org/fructans.
5. Riker C. Low fodmap: Riker Nutrition Consulting: United States. Riker Nutrition.
Accessed February 2, 2024. https://www.rikernutritionconsulting.com/.