Weighing the Best Diet Options for IBD
Nearly every patient with inflammatory bowel disease (IBD) has the same query—which has a not-so-simple answer.
“‘Doctor, what should I eat when living with IBD?’ is likely the most frequently asked question following diagnosis,” says Dr. Maitreyi Raman, an associate professor of medicine at the University of Calgary.
Raman, who’s a gastroenterologist, physician nutrition specialist, and researcher, has closely studied the topic and reviewed the available evidence for dietary patterns that may be of benefit (or not) to patients.
IBD includes Crohn’s disease, which can cause inflammation in any part of the digestive tract and commonly affects the small intestine; ulcerative colitis, limited to the large intestine, or colon, and rectum; and indeterminate colitis, which has features of both Crohn’s and colitis. Symptoms for all forms of IBD include diarrhea, abdominal cramping and pain, fatigue, and unintended weight loss.
Given the life-disrupting nature of the chronic condition, patients are often highly motivated to try different therapies that might bring relief, including making changes to their diet.
“The role of diet as a risk factor and therapy for IBD has been of great interest to patients,” says Raman, who co-authored a review of diets for IBD published in Clinical Gastroenterology and Hepatology in March 2021. Those findings indicate that exclusive enteral nutrition is the most well-supported approach, but isn’t realistic for everyone. Other plans, such as the specific carbohydrate diet, can also be helpful.
Unfortunately, there’s a relative dearth of research on the best diet for IBD. Still, evidence is growing. Over the past decade, the science and understanding of the gut microbiome, which comprises trillions of bacteria (helpful and harmful), have evolved, Raman notes. An imbalance of bacteria in the gut can cause a host of health problems, and may contribute to IBD. And diet can make a big difference.
Before diving into options for what you might put on your plate and in your body if you have IBD, know that experts emphasize that dietary changes aren’t a wholesale substitute for medical treatment.
“Diet is one of many therapies,” says Dr. James Lewis, associate director of the Inflammatory Bowel Diseases Program at the University of Pennsylvania Perelman School of Medicine. “While a diet-based strategy may be preferred and practical for some patients, it may be much harder to implement for other patients.” Certain diets for IBD are quite restrictive, and any significant changes in eating patterns can be challenging to sustain. Still, many patients—especially those with mild to moderate disease—look to diet as one therapy option for IBD.
Experts recommend patients seek professional help in order to develop a personalized eating plan. Therezia Alchoufete, lead dietitian for UPMC Total Care at the University of Pittsburgh, stresses that dietary choices need to be tailored to the individual.
Consider your goals not only related to IBD but also for your overall health. And make sure the focus is on what you can eat, not just what you’re eliminating. Alchoufete talks to patients about making thoughtful choices, while looking to increase variety and nutrients. “My goals for each patient would be to begin building this positive relationship with food—really understanding which foods can help them feel good.”
Exclusive enteral nutrition
The most widely studied and data-supported diet for IBD—and Crohn’s in particular—is an all-liquid, formula-based meal-replacement diet. It’s called exclusive enteral nutrition, and it’s typically prescribed and overseen by doctors. Most commonly recommended for children, this can be consumed by drinking a speciality formula prepared by a doctor, or administered via a feeding tube inserted through the patient’s nose and into the stomach.
There’s strong evidence to show it leads to reduced inflammation and improved healing, and it’s comparable to treatment with steroids in helping patients achieve remission from Crohn’s, which means the disease is no longer active. It also works relatively quickly. Short-term exclusive enteral nutrition programs are designed to induce remission in six to 12 weeks.
However, it’s primarily been studied in children, not adults. And there’s an even more obvious con: it’s challenging to stick with the diet “from a quality-of-life standpoint, since it requires entirely eliminating normal food,” says Dr. Ashwin Ananthakrishnan, a gastroenterologist in the Digestive Healthcare Center at Massachusetts General Hospital.
There have been some attempts to replicate the success of exclusive enteral nutrition with solid foods. A small 2019 study published in Gastroenterology found consuming an individualized “ordinary food-based” diet with a similar composition to exclusive enteral nutrition, dubbed CD-TREAT, led to changes in the microbiome that mirrored those found with exclusive enteral nutrition. The diet was also associated with decreased gut inflammation and well tolerated by children and adults in the study.
CD-TREAT is prescribed and personalized by a doctor or dietitian, and it excludes certain dietary components like gluten (so no wheat), lactose, and alcohol. It incorporates all the macro-nutrients (with more protein and fat and fewer carbs) and reduces fiber. So a person might eat, for example, a rice cereal with nondairy full-fat milk for breakfast, a grilled cheese on gluten-free bread with an apple for lunch, and grilled salmon with potatoes and a sliced cucumber for dinner.
Although more study is needed, the findings provide a framework for treating active Crohn’s without relying on a liquid diet.
Crohn’s disease exclusion diet
Successful IBD diets eschew the traditional red-meat-heavy, sugary, processed Western diet that wreaks havoc on gut health. Research suggests the shift toward that way of eating bears much blame for increases in IBD rates—even in the East, like Japan, where the Western diet has been adopted as well.
To counter that, the Crohn’s disease exclusion diet seeks to cut out Western diet staples, such as processed meat, artificial sweeteners, and alcohol, which may affect gut health. Evidence from high-quality comparative trials demonstrates the diet’s effectiveness in relieving symptoms and reducing inflammation—and it could start to work within three to six weeks.
A study published in 2019 in Gastroenterology demonstrated that for children with mild to moderate Crohn’s disease, the Crohn’s disease exclusion diet can induce and sustain remission. A subsequent study published in November 2021 in the Lancet Gastroenterology & Hepatology found it was effective for inducing and maintaining remission in adults with mild to moderate Crohn’s.
But as its name indicates, the Crohn’s disease exclusion diet is highly restrictive. In the 2021 study examining the approach, participants were only allowed to have chicken breast, eggs, and partial enteral nutrition—or liquid formula for a portion of their calories—as sources of animal protein, and limited to certain fruits and vegetables, for the first six weeks. The second six-week phase involved the gradual introduction of almost all fruits and vegetables, while restricting beef and legumes, and allowing one slice of whole-grain bread daily.
This 12-week period, called the induction phase, is most important for achieving remission. The third six-week period, the maintenance phase, adds back more foods to make the diet more sustainable while maintaining results.
Even with those adjustments, the diet may be a challenge to adhere to in the long term, and requires in-depth planning plus home cooking, said Dr. Henit Yanai, head of the IBD Center at the Rabin Medical Center in Petah Tikva, Israel.
Specific carbohydrate diet
The specific carbohydrate diet, which is a grain-free elimination diet, is based on the idea that consuming certain complex carbs feeds unhealthy bacteria, causing an overgrowth of these “bad” bacteria in the small intestine. That in turn could contribute to inflammation.
Based on that concept, the diet avoids everything from table sugar to grains—including wheat and corn—starchy foods like potatoes, and other exclusions. Adherents can, however, have meats, fish, and poultry without additives, veggies (fresh or frozen but not canned with any additives), and most nuts and oils. They can also use honey as a sweetener.
However, experts express concern about patients’ ability to sustain the diet and advise that the eating plan should be monitored by a dietitian.
The Mediterranean diet is another approach recommended to some IBD patients. It’s been well studied and is highly touted for its overall benefits, including for heart and brain health. Best of all, it’s an eating style recommended for nearly everyone and is easier to follow than more restrictive diets. If you follow this plan, you’ll load up on fruits and vegetables, whole grains, nuts, and lean protein such as fish.
The Mediterranean diet was featured in a rare and prominent head-to-head comparison of diets for IBD, led by Lewis, called the DINE-CD trial. The study, which was published in May 2021 in the journal Gastroenterology, pitted it against the specific carbohydrate diet. More than 190 patients with mild to moderate Crohn’s were involved in the research.
The study found that both diets similarly helped patients achieve symptomatic remission and improved their quality of life. Neither option had a significant impact on a biomarker used to measure inflammation, something the Crohn’s disease exclusion diet has been documented to help improve.
But since the Mediterranean approach allows a wide variety of foods and is better studied for its overall health benefits, Lewis and other doctors tend to recommend it over the specific carbohydrate diet.
Patients whose Crohn’s disease is well controlled in regards to inflammation but who are still suffering from irritable bowel symptoms may benefit from the low-FODMAP diet. (That stands for fermentable oligo-, di-, monosaccharides, and -polyols.) Primarily promoted for IBS, this diet aims to exclude short-chain carbohydrates, or sugars, that are poorly absorbed by the small intestine. Foods that are restricted, or avoided, on this diet initially include wheat, dairy, certain fruits like apples, and veggies such as artichokes and asparagus.
“If people have significant pain and bloating, and nothing else is working, then perhaps I might try the FODMAP elimination diet,” says Dr. Jean Fox, gastroenterologist at Mayo Clinic in Rochester, Minn. But generally she has patients follow the approach under the supervision of a dietitian, so they don’t continue the restrictive phase for more than six weeks.
Following that, in the reintroduction phase, foods are slowly reintroduced over six to eight weeks, to see which might be causing trouble. After identifying which might cause symptoms, those foods can be avoided or restricted. The downside, says Fox, is that patients who don’t see any symptom relief following this diet may be unnecessarily restricting a wide range of foods.