FODMAPs, IBS, fruits, grains, beans, sugar alcohols, polyols, fructose, galatans, lactose, dairy


Ever heard of a FODMAP? It sounds like high-tech terminology, but it actually refers to food for your gut bacteria. (And gut bacteria are definitely ancient and primordial, although absolutely essential.) FODMAP stands for Fermentable Olig-, Di-, and Mono-saccharides And Polyols.  I admit, none of those words sound like food. They’re just fancy words for small carbohydrates that bacteria love to eat. Our food supply is full of these small carbs, and they aren’t really bad guys-in fact, they can feed some of the good bacteria that we need in our guts for health. Many people have no trouble with them. But not everyone tolerates them, and we’ll talk about why in a minute.

In 2005, dietitians and physicians at Monash University in Australia wondered why so many of their clients with IBS (irritable bowel syndrome-a collection of symptoms with variable causes) felt better when they didn’t eat legumes, dairy, wheat, and certain fruits and vegetables. They developed and tested a theory that a diverse group of these small carbohydrates were being fermented by gut bacteria before they could be absorbed by the host (us humans). Fermentation means that as bacteria eat these carbs, the bacteria produce gas. (Think of how gas bubbles up from a jar of fermented vegetables or a carton of old fruit juice.) And gas, bloating, nausea, and often diarrhea or constipation are classic symptoms of IBS. Sue Shepard, Peter Gibson and colleagues figured out that the culprits are Lactose, Fructose, Fructans, Galactans, and Polyols (sugar alcohols like sorbitol).

IBS, FODMAPs, garlic
IBS, FODMAPs, beans, legumes

If an individual has had part of their intestine removed (short gut), or has excessive bacteria present in the small intestine (small intestinal bacterial overgrowth-SIBO), or has the wrong mixture of bacteria in their colon, this fermentation process can go into overdrive, producing more gas than the gut can handle. Other fermentation products produced by the bacteria can irritate the intestine, causing it to move too quickly, or to churn around erratically, instead of moving smoothly and rhythmically “downstream”.  In addition, these small carbs attract water, which can contribute to diarrhea. So in these cases, avoiding high-FODMAP foods can greatly reduce the pain and discomfort associated with IBS. In fact, studies indicate that 75% of all people with IBS symptoms feel better when avoiding high-FODMAP foods.

So what are these foods? Well, lactose is obviously from dairy, fructose is in high-fructose corn syrup and fruits (the most problematic fruits are the ones that contain more fructose than glucose, like apples), fructans (which are chains of fructose strung together) are present in wheat and in some vegetables, galactans are present in legumes and certain vegetables, and polyols are found in some fruits, some vegetables, and some sweeteners. The table at the end of this article lists some of the common high-FODMAP foods. For more detailed information, see Kate Scarlata’s website, She is the leading expert in the US on the low-FODMAP diet, and has tons of information on her site.

If you have IBS symptoms and want to try a low-FODMAP diet, I recommend you start by taking out all high-FODMAP foods. Watch the portion sizes on moderate FODMAP foods, which you will find on Kate’s website. Think of FODMAPs in your diet as additive. You may be able to tolerate a few, but the more you add, the more discomfort you will feel. It’s best to remove them all, then once you feel better, slowly add them back one at a time to test for tolerance. Most people will have more trouble with one or two categories, but some people will have to keep all FODMAPs in their diet to a minimum to find relief. If you need help, don’t hesitate to consult with a dietitian who has experience with low-FODMAP diets (I’m one of them!).

Lisa Scranton, MS, RDN, LD

Nutritionist. The Center for Medicine and Healing Arts

610 Eastbury Dr. Suite 5 Iowa City Iowa 52245

319-358-9510 F. 319-358-9524 E. [email protected]


Foods High in FODMAPs

Milk, evaporated milk, yogurt, ice cream, custard, and certain cheeses such as ricotta, cottage, and mascarponeFruits such as apples, pears, peaches, mangoes, and watermelon; coconut milk; coconut cream; dried fruits; and fruit juices

Sweeteners such as agave and honey

HFCS-based products such as BBQ sauce, ketchup, and pancake syrup

Alcohol such as sherry and port wine

Sodas with HFCS (this is most soda)

Vegetables such as artichokes, asparagus, Brussels sprouts, broccoli, beetroot, cabbage, chicory, garlic, leeks, okra, onions, radicchio lettuce, shallots, and snow peas

Grains such as wheat and rye

Added fiber such as inulin and fructo-oligosaccharides;
watch items such as probiotic supplements, granola bars, and frozen desserts

Fruits such as watermelon


Chickpeas, lentils, kidney beans, and soy products

Vegetables such as broccoli

Fruits such as apples, apricots, blackberries, cherries, nectarines, pears, peaches, plums, prunes, and watermelon

Vegetables such as cauliflower, button mushrooms, and snow peas

Sweeteners such as sorbitol, mannitol, xylitol, maltitol, and isomalt (sugar-free gums/mints, cough medicines/drops)

Sucralose (Splenda)

Karyn Shanks MD


Karyn Shanks, MD, is a physician who lives and practices in Iowa City. Her work is inspired by the revolutionary science of Functional Medicine, body-mind wisdom, and the transformational journeys of thousands of clients over her twenty-eight year career. She believes that the bones of healing are in what we do for ourselves.

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