What’s the word on the low FODMAP diet?

Researchers have zeroed in on one potential trigger for IBS symptoms: FODMAPs. The small carbohydrates are poorly absorbed in the gut.

People with irritable bowel syndrome have hypersensitive guts that react to certain foods or medications or to stress and anxiety. It can be debilitating.

“IBS often comes with bloating, pain, and diarrhea or constipation or a mix of both,” says Shanti Eswaran, a gastroenterologist and assistant professor of medicine at the University of Michigan Medical Center.

Doctors don’t know what causes IBS, which affects an estimated 10 to 15 percent of U.S. adults. They even have trouble diagnosing it. “There’s no specific test, imaging, blood marker, or endoscopy that doctors use,” explains Eswaran. “It’s diagnosed based on symptoms.”

And doctors don’t have a great way to treat IBS. “The focus has been on medications that reduce gut spasm, antidepressants that decrease gut sensitivity, laxatives for people with constipation, or anti-diarrheals if that’s an issue,” says Eswaran. “But medications don’t work in many patients, or patients suffer side effects from them.”

What about avoiding foods that trigger symptoms?

Researchers have zeroed in on one potential culprit: FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols).

“They’re small carbohydrates that are poorly absorbed in the gut,” Eswaran explains.

FODMAPs that aren’t absorbed are eventually fermented by gut microbes. “Everyone’s gut microbes ferment FODMAPs,” says Eswaran. “But people with IBS, we think, are more sensitive to FODMAPs. And that can lead to excess gas, bloating, and diarrhea.”

FODMAPs are in all kinds of foods, from milk, yogurt, and soft cheeses to beans, lentils, and wheat. They’re also in some fruits and vegetables like apples, watermelon, cauliflower, broccoli, onions, garlic, peaches, prunes, and asparagus. Sugar alcohols (xylitol, sorbitol, mannitol, and maltitol) and inulin (chicory root) are also FODMAPs.

Trying the low FODMAP diet

Since FODMAPs are in many healthy foods, researchers don’t recommend cutting all FODMAPs for very long.

“We recommend a short-term elimination diet,” says Eswaran. “We usually tell people to cut out all FODMAPS for two to four weeks, under the instruction of a dietitian. If they improve, they systematically add back different groups of FODMAPs to determine what their specific triggers are.”

And that varies. “For example, some people will say, ‘I do fine with wheat and beans, but dairy and onions are an issue,’” says Eswaran.

In a handful of studies, people who cut back on FODMAPs reported fewer IBS symptoms. In the largest one, Eswaran and her colleagues compared a low FODMAP diet to standard advice for IBS in 84 patients.

“We told the standard-advice group to avoid trigger foods—the ones they know cause symptoms,” she explains. “We also told them to avoid large amounts of alcohol and caffeine and to eat small, frequent meals and eat on a regular basis.”

After four weeks, about half the people on each diet reported “adequate relief.” But abdominal pain and bloating were lower in those on the low FODMAP diet.

The bottom line

A low FODMAP diet may help relieve IBS symptoms. If you want to try it, a good starting point is this University of Michigan website: http://myginutrition.com/diet.html.

Photo: © Picture Partners/fotolia.com.

The information in this post first appeared in the May 2017 issue of Nutrition Action Healthletter.

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11 Replies to “What’s the word on the low FODMAP diet?”

  1. I follow the FODMAP plan. My problem is that for vacation this year I need to be able to eat foods that are in Ireland. I also need to find a “Ginger” capsule etc. that works. I have tried some ginger teas & some capsules. They seem to be too strong for me or in other words, cause the symptons. Please give me an idea of something to try that would help.

  2. The low FODMAP diet changed my life and after working in the food industry for 30 years (I am a former Bon Appetit editor and author of 17 books) and struggling with IBS all that time. I am now devoting my time to spreading the word! Our site, FODMAPeverday.com has the world’s only Monash University Certified Low FODMAP recipes free to the end user, we have a team of trained registered dietitians and I also co-wrote a book with Kate Scarlata RDN, The Low-FODMAP Diet Step by Step. Our site is recommended by the U of Michigan team and we want to help all of you learn to THRIVE on this diet. I hope you find our resources helpful.

  3. Has anyone done a study on the varying gut bacteria in the colons of those with IBS? Maybe there are critical bacteria that are missing?

  4. A number of years ago , after trying everything for IBS and having nothing work, I happened upon Dr. David Williams probiotics. I have never looked back! Very, very rarely when I am under extreme stress, do the IBS symptoms reappear. But I can’t tell you how happy I am to have found this over-the-internet solution. I’ve tried others when I’ve forgotten to pack mine, but nothing else works. By the way, I am NOT an advertisement! Just very passionate about getting the word out to people who have found nothing else that works.

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