Irritable bowel syndrome (IBS) is a condition that negatively affects the digestive system and can cause unpleasant symptoms such as stomach cramps, bloating, and diarrhea. Low FODMAP diets can be beneficial for those with IBS, but this strict diet requires proper nutritional supervision. Learn more about how dietitians can introduce a low FODMAP diet for IBS clients.

IBS (irritable bowel syndrome) is one of the most common gastrointestinal disorders in the world, affecting 10-15% of the population.

Some hallmark symptoms include abdominal pain, bloating, gas, diarrhea, and constipation, all of which can wreak havoc on one’s quality of life. While medications can help, nutrition and lifestyle changes can also make a difference, which is why people are turning to diet to help manage IBS [6,7].

One leading area of interest is the low FODMAP diet, which is a specialized diet designed to improve IBS symptoms.

Before diving into more details about what a low FODMAP diet is, let’s first start off by talking about what FODMAPs are and how nutritional care looks for dietitians working with IBS clients.

What are FODMAPs?

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are short-chain carbohydrates that the small intestine absorbs, often poorly [1]. There are some specific cut-offs to be considered high FODMAP, being that it contains more than one of the following [2]:

  • Oligosaccharides: 0.3 grams of fructans or galacto-oligosaccharides;
  • Disaccharides: 4.0 grams of lactose;
  • Monosaccharides: 0.2 grams more fructose than glucose;
  • Polyols: 0.3 grams of mannitol or sorbitol.

High FODMAP vs. low FODMAP foods

High FODMAP foods put additional strain on the body’s digestive system, which can lead to digestive issues. Studies have found that those who eat a diet high in FODMAPs tend to experience more frequent and severe gastrointestinal issues than those on a low FODMAP diet [7].

Some types of foods that are high in FODMAP include:

  • Dairy (such as milk, yogurt, and ice cream);
  • Wheat (such as cereals, bread, and crackers);
  • Beans;
  • Lentils;
  • Certain vegetables and fruits (such as garlic, onions, apples, mangos, cherries, peaches, pears, and artichokes) [3].

A low FODMAP diet focuses on eliminating (or limiting) certain foods that negatively affect the digestive system. Research shows that those with IBS who follow a low FODMAP diet experience decreased intestinal discomfort, bloating, and gas and improved digestion and stool consistency [7].

Some low FODMAP foods include [3, 4]:

  • Brown rice;
  • Certain vegetables and fruits (such as blueberries, kiwi, oranges, strawberries, carrots, eggplant, spinach, and zucchini);
  • Tofu;
  • Nuts and seeds;
  • Eggs.

While navigating IBS can be tricky, there are many nutritious food substitutions that will still support your clients’ nutritional needs.

Treating IBS with low FODMAP diets

To provide quality nutritional support for IBS clients, it’s recommended to compile a comprehensive medical history which includes dietary restrictions, medications, diagnoses, and family history. It’s important to have adequate background information on your client because this may impact how they follow a low FODMAP diet [8].

Low FODMAP diets also require proper nutritional supervision. Monitoring what and how much your client is eating (as well as examining their medications, physical activity, work status, and menstrual cycle time) are all factors that can greatly impact the way your client feels.

When your client starts a low FODMAP diet, there are many changes to both their diet and lifestyle, so providing good nutritional care will go a long way in improving their overall health. Here are some tips for how you can introduce your client to a low FODMAP diet:

  • Meet nutritional needs. Many foods that contain a good source of fiber and calcium are also high in FODMAP [7]. To meet your client’s nutritional needs, you can replace some high FODMAP foods with lower FODMAP alternatives. Examples for fiber-friendly low FODMAP foods include strawberries, green beans, spinach, quinoa, flaxseeds, and gluten-free brown bread. To meet calcium requirements, oats, rice milk, lactose-free yogurt, hard and aged cheese, and nuts are good low FODMAP options. As always, be sure to monitor your client’s nutritional status to determine if supplementation is necessary.

  • Be aware of lactose intolerance. Not all patients with IBS are lactose intolerant [9]. Lactose is a disaccharide, so it qualifies as a high FODMAP food, but it may not aggravate everyone who has IBS. However, you should limit lactose-containing foods if your client is lactose intolerant.

  • Certain high FODMAP foods can be tolerated. This diet is meant to limit high FODMAP foods but not necessarily eliminate them completely. Research shows that even if someone benefits from a low FODMAP diet, having a small amount of the gut microbiota contained in high FODMAP foods can improve gut health and decrease some gastrointestinal discomfort [11].

  • Eliminate, and then reintroduce. An elimination diet may be helpful when looking at triggering foods [12]. This can be done in a three-step process: 1) eliminate all high FODMAP foods from your client’s diet for 2-6 weeks; 2) once your client experiences positive effects, start a 6-day repetitive schedule of introducing foods while monitoring your client’s symptoms; 3) continue on until all FODMAP categories have been addressed and your client can determine what their body tolerates.

  • Consider supplementation. Probiotics have been proven to benefit those with IBS, as they can help reduce bloating, abdominal discomfort, and flatulence [13]. Be sure to advise your client of how and when to take probiotics while on a low FODMAP diet.

  • Keep a food journal. Encourage your client to keep a food and habit journal to document their daily diet, sleeping habits, physical activity, and stress levels (as this can be a trigger and cause flare-ups). This will provide you with a more complete picture of their journey with IBS and will allow you to make more accurate dietary and lifestyle suggestions.