Much Ado about FODMAPs

Low-FODMAP diets have getting some press lately!  But what exactly are they?

For starters, “FODMAP” stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. (Obviously there’s an acronym for a reason).

Oligosaccharides, disaccharides, monosaccharides, and polyols are short chain carbohydrates like lactose, fructose, and sugar alcohols. These carbohydrates are referred to as “fermentable” because they can be digested by bacteria in the large intestine.

Who needs a low-FODMAP diet?

Unlike many diets out there, the low-FODMAP diet is not a weight loss diet for otherwise healthy people. Low-FODMAP diets are intended as a short-term (approximately 21 day) intervention to relieve symptoms of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). IBS is a gastrointestinal disorder with symptoms like abdominal pain, bloating, constipation, and diarrhea. There is no known cure, but low-FODMAP diets may help manage IBS symptoms. IBD describes two conditions (Crohn’s disease and ulcerative colitis) that cause inflammation in the gastrointestinal tract resulting in symptoms including a change in bowel habits, abdominal pain, and fatigue.

What foods have FODMAPs?

FODMAPs are found in many different foods from fruits (apples, cherries, mangos) to vegetables (artichokes, onions, peas) to soft cheeses, yogurt, and honey. Polyols are often used to sweeten chewing gums.

It’s impossible to tell whether a food is high or low in FODMAPS by just looking at it. For instance, cherries are high in FODMAPs, while blueberries are not. This does not mean that cherries are somehow less healthy than blueberries. FODMAPs are perfectly safe and actually beneficial. Removing them from the diet for a short period of time, though, may be helpful for some individuals with IBS or IBD.

How does a low-FODMAP diet affect IBS and IBD symptoms?

The fermentation of FODMAPS in the large intestine produces gas, which can lead to flatulence, borborygmus (rumbling and gurgling in the intestines), and bloating. They also draw water into the large bowel, which can lead to diarrhea. By reducing the amount of all of these short chain carbohydrates, a low-FODMAP diet essentially reduces gastrointestinal symptoms that may be exacerbated by certain foods. While the research on low-FODMAP diets is emerging, initial studies and reviews suggest that restricting FODMAPs reduces “functional gut symptoms,” and that even a short term restriction seems to have a lasting effect after FODMAP-containing foods are re-introduced into the diet.

I have some of those IBS and IBD symptoms. Should I go on a low-FODMAP diet?

IBS and IBD diagnoses should only be made by a medical practitioner. A low-FODMAP diet is very restrictive, can be challenging to follow, and may result in dietary insufficiencies if followed for too long. Monash University in Australia, where the diet was developed, recommends starting this diet with the assistance of a registered dietitian.

The low-FODMAP diet may be in the news more often these days but that does not mean it is an appropriate or safe diet for everyone. Low-FODMAP diets are specific diets meant for a specific population to follow for a short time. There are plenty of eating plans and tools out there meant for healthy adults, whatever your health goal may be.    

Julie Hess, IFIC 's Sylvia Rowe Fellow contributed to this article.