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The low-carbohydrate diet is used for temporary relief from IBD symptoms. Foods are eventually reintroduced. Getty Images
  • Researchers say a low-carbohydrate diet known as FODMAP can help relieve symptoms of inflammatory bowel disease (IBD).
  • The diet has already been proven to help people with irritable bowel syndrome (IBS).
  • The relief for people with IBD is designed to only be temporary. Foods are eventually reintroduced as a person’s intestinal system stabilizes.

Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are two different conditions with similar abbreviations and a few shared symptoms, such as diarrhea, abdominal pain, and bloating.

IBS is a collection of symptoms that can come and go, while IBD is an umbrella term that envelopes more chronic conditions such as Crohn’s disease and ulcerative colitis that experts believe may be triggered by problems in a person’s immune system.

But new research suggests a diet that’s been shown to decrease symptoms in one may be helpful in finding relief for people with the other.

It’s known as the low-FODMAP diet.

FODMAP stands for fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols.

They are various types of carbohydrates and sugar alcohols that are commonly found in foods such as wheat, dairy, onions, and garlic.

Because they aren’t digested in the first part of the intestine, these substances travel farther through our system and are fermented by our gut bacteria.

This process can create unwanted side effects, such as gas and painful bloating.

That’s of particular concern for people with IBS and IBD.

Researchers at King’s College London recently published a study in the journal Gastroenterology that suggests a low-FODMAP diet may improve certain symptoms for people with IBD.

The diet has already been documented as helpful for people with IBS.

To test its effectiveness in people with IBD, researchers recruited 52 people with IBD that had persistent gut-related symptoms — like flatulence and swelling of the stomach — despite there not being any ongoing inflammation in their intestines.

Half of those patients were put on a low-FODMAP diet for a month.

At the end, half of the patients on the low-FODMAP diet reported “adequate relief” of the symptoms affecting their gut, and rated their quality of life higher than those who didn’t follow the diet.

The research team also noticed that following the low-FODMAP diet reduced certain bacteria in the gut, which may help reduce inflammation overall.

Selina Cox, the study’s lead researcher and a doctoral research dietitian at King’s College London, said while a low-FODMAP diet has been shown to help reduce unwanted symptoms for people with IBS, this latest study was the first randomized trial on people with IBD.

But there’s a catch: A low-FODMAP diet isn’t a long-term solution.

It’s meant to help people rid their diets of potentially offending food only to gradually reincorporate those foods.

“In clinical practice, the low-FODMAP diet is followed by a phase of gradual FODMAP reintroduction,” Cox said in a press release. “It is important to establish what the effects of FODMAP reintroduction are on the gut and whether reintroduction reverses the bacterial changes that were observed during the low-FODMAP diet.”

Cox’s research team now intends to study how the low-FODMAP diet affects a person in the long term, as well as what it does to IBD symptoms and gut bacteria when foods are reintroduced.

One potential pitfall of following a low-FODMAP diet longer than a few weeks is the risk of nutrient deficiencies such as fiber and minerals, including calcium and vitamins A, C, and D.

That’s because the foods eliminated from the diet include fruits, vegetables, and some dairy products.

Silvia Delgado, MS, RD, CDE, a health educator and registered dietitian who works at Kaiser Permanente in Baldwin Park, California, says a low-FODMAP eating plan should be individualized to make sure it meets the needs of each person.

“This diet is low in fiber, which can exacerbate constipation,” she told Healthline. “The long-term effects of a prolonged low-FODMAP diet may have other consequences on other chronic conditions, since fiber has been shown to be beneficial in the prevention of diabetes, heart disease, and weight management.”

Ideally, Delgado says, the low-FODMAP diet should only be followed for 2 to 6 weeks.

That allows the gut to settle itself before foods are reintroduced back into a person’s diet.

First, a person enters the elimination phase, which includes completely avoiding foods that could trigger symptoms. These certain vegetables, fruits, beans, lentils, wheat, dairy products with lactose, high fructose corn syrup, and artificial sweeteners.

Next, the person reintroduces those foods, one at a time, in small portions.

“The reintroduction phase is important because it will help you identify which foods cause symptoms,” Delgado said. “You may be asked to keep detailed record of triggers and symptoms.”

The last step is maintaining, which involves returning to a more stable diet and only eliminating problematic foods.

While the research into a low-FODMAP diet and IBD is relatively new, its use in people with IBS is more well-established, even if it hasn’t been around that long.

Dr. Shanti Eswaran, an associate professor of gastroenterology at the University of Michigan, says using a low-FODMAP diet to treat IBS was unheard of until about a decade ago.

It was welcomed, as there aren’t many good medications to treat the disorder, and more people are open to making dietary changes than taking a pill.

“But the goal is not to stay on a low-FODMAP diet indefinitely,” Eswaran told Healthline.

The goal, she said, is to follow the eliminate-and-incorporate method, preferably under the supervision of a doctor and a dietitian.

But the FODMAP diet isn’t a roadmap to health.

Some offending foods do have health benefits, while other foods might cause problems in a person’s intestinal system.

“These are found in healthy foods,” Eswaran said. “But they’re also found in unhealthy foods.”