FODMAP: A Primer

FODMAP: A Primer

Getty/ Noel Hendrickson

If you’ve recently discovered you have irritable bowel syndrome (IBS), you may want to jump right into a low-FODMAP diet. Here’s what you need to know about FODMAP.

The low-FODMAP diet has been designed as a tool that can help up to 75 percent of irritable bowel syndrome (IBS) sufferers gain good symptom management, through identifying foods that trigger symptoms. This statistic is exciting, and I know it’s tempting to plunge straight into the low-FODMAP diet, but it’s important that you check first whether it’s right for you.

  • Check with your doctor before changing your diet and get a clear diagnosis. Make sure your doctor has ruled out celiac disease (you need to be eating gluten for these tests), inflammatory bowel disease, and bowel cancer, as these conditions can have similar symptoms to IBS.
  • If you have other medical conditions, ask if the low-FODMAP diet is a suitable symptom-management option.
  • Get a referral to a FODMAP-trained dietitian. The low-FODMAP diet is a restrictive medical diet and it’s important that you have a dietitian who can help guide you and tailor the diet to your needs.
  • If you have an eating disorder, use food for emotional support, or are obsessive about your food, then the low-FODMAP diet might not be right for you and you need to seek specialized medical advice.
  • Check with a medical professional before placing children, elderly people, or pregnant women on the diet as these groups all have different nutritional needs to support their bodies. The low-FODMAP diet is a restrictive diet and may not be appropriate.
  • Make sure you are able and prepared to restrict your diet for a two- to six-week period while you see if the diet helps you gain good symptom management.
  • Be mentally prepared to reintroduce some high-FODMAP foods back into your diet after two to six weeks to support your long-term gut health.

What Are FODMAPs?

In really simple terms, FODMAP is an acronym that represents a group of fermentable sugars (short-chain carbohydrates) that are found in a wide range of foods and can trigger unpleasant gastrointestinal symptoms in some people. Let’s break down the acronym:

Fermentable: The process through which gut bacteria break down undigested carbohydrates and produce gases (hydrogen, methane, and carbon dioxide) as a side effect.

Oligosaccharides: There are two main types of oligosaccharides. The first type is fructo-oligosaccharides (FOS or fructans), found in foods such as wheat, rye, onions, and garlic. The second type is galacto-oligosaccharides (GOS or galactans), found in legumes and pulses. Have you ever wondered where the saying “beans means farts” came from? A fun fact is that humans aren’t actually designed to be able to break down oligosaccharides and this is why they can make everyone windy. Unfortunately, for those of us with a sensitive gut, this is more painful than it is for others.

Disaccharides: The only disaccharide classified as a FODMAP is lactose. Lactose contains two sugar units that need to be separated by an enzyme called lactase. If you don’t have enough lactase enzymes, your body won’t be able to separate the sugar units and you will malabsorb lactose. Lactose is found in milk, soft cheese (e.g., ricotta), yogurt, and ice cream.

Monosaccharides: Fructose is a monosaccharide. Because glucose can help your body absorb fructose by acting as a “co-transporter,” only excess fructose is considered high FODMAP. When you consume more fructose than glucose, your body may not be able to effectively process the fructose, resulting in malabsorption, which can trigger symptoms. High-FODMAP foods that contain excess fructose include honey, mango, apples, pears, and high-fructose corn syrup.

And Polyols: Polyols are sugar alcohols that are found naturally in some fruit and vegetables. They can also be man-made and used as artificial sweeteners. These sugar alcohols won’t make you drunk but they are incompletely absorbed across the small intestine, which is why they can cause gastrointestinal symptoms. Polyols include mannitol and sorbitol. Grab the Monash University Low-FODMAP Diet app for up-to-date lists of high- and low-FODMAP foods.

Read “IBS Is Real, It's Not Just in My Head.”

How Do FODMAPs Trigger Symptoms?

We’ve just learned that FODMAPs are a large group of dietary sugars (short-chain carbohydrates) that can lead to an upset gut. The trouble begins when our small intestine fails to absorb these carbohydrates. The presence of FODMAPs causes water to be dragged into the small intestines, which can lead to diarrhea.

The malabsorbed sugars then travel on to our large intestine where they become “fast food” for our gut bacteria. FODMAPs provide these healthy bacteria with energy; however, as the gut bacteria feast, they rapidly ferment these short-chain carbohydrates. This produces large quantities of gases (hydrogen, methane, and carbon dioxide). These gases are why FODMAPs cause flatulence and can lead to bloating and constipation.

This combination of excess water and gas production in the digestive tract causes our intestines to expand, making us bloated. This bloating distends our intestinal walls, irritating our highly sensitive nerve endings and triggering pain signals.

To combat these symptoms, the low-FODMAP diet works by reducing the overall FODMAPs consumed to a level our bodies can tolerate, helping to reduce diarrhea, flatulence, bloating and distention, abdominal pain, and constipation.

Excerpted from The Gut-Friendly Cookbook. Copyright 2020 by Alana Scott. Reproduced by permission of The Countryman Press. All rights reserved.

Try this easy and gut-friendly recipe for Crunchy Falafel

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