A new case study of a man with Crohn's disease details how his symptoms disappeared after he stopped eating animal-based and highly processed foods. He switched to a diet comprising only plant foods after a year of standard treatment that did not resolve the condition.

Crohn's is a type of inflammatory bowel disease (IBD) with painful symptoms. The condition affects millions of people around the world. Studies have shown that diets comprising fruits, vegetables, legumes, and whole grains can help prevent and treat diabetes, heart disease, some cancers, high blood pressure, and other long-term conditions.

The investigators behind the new study propose that, subject to further research, Crohn's disease should perhaps join that list. A recent paper in the journal Nutrients gives details of the case together with the researchers' findings and conclusions.

"This case study," says study co-author Dr. Hana Kahleova, director of clinical research at the Physicians Committee for Responsible Medicine in Washington, DC, "offers hope for hundreds of thousands of people [experiencing] the painful symptoms associated with Crohn's disease."

IBD: A global disease that is 'on the rise'

Crohn's disease is one of two main forms of IBD. IBD is a condition of persistent inflammation that results in damage to the digestive, or gastrointestinal, tract. The other form of IBD is ulcerative colitis.

Although it most often affects the small intestine, Crohn's can occur in any part of the digestive tract between the mouth and the anus. Ulcerative colitis mainly affects the colon, or large intestine, and the rectum.

The symptoms of Crohn's disease tend to include abdominal pain, diarrhea, bleeding from the rectum, weight loss, and fatigue. They can vary from person to person and can come and go.

The study authors note that around half of people with Crohn's disease require surgery within 10 years of receiving a diagnosis. Only a small minority achieve "prolonged clinical remission."

Scientists are undecided about the exact causes of IBD. However, they suspect that the condition arises from a complex interplay of several factors that include genetics, diet, lifestyle, environment, immune system changes, and gut bacteria imbalances.

One 2015 study paper states that IBD is a global disease that is on the rise in every continent. It already affects more than 1 million people in the United States and 2.5 million people in Europe.

The health-care costs of IBD are substantial. However, these do not reveal the real burden of a disease that can disrupt careers, impair quality of life, and stigmatize people socially.

Treating Crohn's disease with diet changes

In the study paper, Dr. Kahleova and colleagues cite research in which people with Crohn's disease benefited from following a Crohn's Disease Elimination Diet (CDED). These have shown remission rates ranging from 62% to 71%.

The CDED and a whole-food, plant-based diet have some features in common, including significant reduction or omission of processed food and dairy products and an increased intake of dietary fiber.

The man in the recent study was 25 years of age when he received a diagnosis of Crohn's disease. This had followed several years of experiencing symptoms such as bloating, bouts of abdominal pain, fatigue, ulcers, and nausea. The authors note that doctors classed him as "high risk due to his moderately severe inflammation, severity of symptoms, diagnosis under the age of 30, and his perianal disease."

After receiving intravenous infusions of infliximab every 8 weeks for 1 year, the symptoms lessened but the man did not "achieve clinical remission." Tests revealed "mildly clinically active disease," and he continued to experience bouts of abdominal pain, bloating, and fatigue.

During his second year of using the medication, the man gave up eating animal and processed foods for 40 days for religious reasons. While he was following a plant-based diet, "he experienced a complete resolution of symptoms."

Before switching to the plant-based diet, his eating habits had been typically American, with daily intakes of meat, dairy, processed foods, and refined grains and modest intakes of fruits and vegetables.

Full mucosal healing with no visible evidence

Because of the effect it had in completely eliminating his symptoms, the man decided to adopt a plant-based, whole-food diet for good. He vastly reduced his consumption of processed foods and limited his intake of animal products to a maximum of one serving per week.

He did lapse from this regimen occasionally. When this happened, his symptoms—such as nausea, fatigue, bloating, and mouth ulcers—returned, but they disappeared again when he got back on track. At the same time, he also began to change his lifestyle. He took up yoga, running, and strength training.

After 6 months of sticking to the new diet and lifestyle, a follow-up colonoscopy of the affected part of his digestive tract revealed "complete mucosal healing with no visible evidence of Crohn's disease."

The man was then able to come off his medications completely. That was in August 2017, and the authors note that he has reported "no relapses since."

Speculating on the reasons behind the results in this case, the researchers mention two points; the first is that a plant-based diet promotes microbial diversity in the gut.

The second point they make is that a diet high in fiber also promotes the growth of bacteria that ferment fiber. The byproducts of this fermentation include short-chain fatty acids, which, among other things, can strengthen immunity to disease-causing agents and help control essential functions in the gut.

Readers should note that this study only covers a single case. What works for one person may not work for others. Scientists should now conduct more research that involves larger groups of people with and without Crohn's disease to confirm whether a plant-based diet can put Crohn's disease into complete remission.

"This case study supports the idea that food really is medicine."

—Dr. Hana Kahleova