People who have Crohn's disease often seek to ease their symptoms by changing what they eat, and new research suggests the Mediterranean diet may be their best bet.
The study evaluated one of the commonly used diets for Crohn's disease, known as the specific carbohydrate diet (SCD), comparing it with the Mediterranean diet, which is sometimes recommended by doctors for its heart health benefits, but not for inflammatory bowel diseases like Crohn's.
The scientists found that both diets reduced symptoms almost equally, but the study concluded that the greater ease of following the Mediterranean diet might make it one that patients would prefer to follow.
"Physicians are seeing patients who are on increasingly restrictive diets," said study co-author Dr. Arun Swaminath. He is an associate professor in the Zucker School of Medicine at Hofstra/Northwell and an assistant professor at Feinstein Institutes for Medical Research at Northwell Health in New York.
The downside of these tightly controlled eating regimens is that patients may not be getting enough calories or nutritional variety, he said. An easier-to-follow diet may help with that.
"It's the idea of helping my patients avoid a pathway of increasingly restrictive foods for them to feel like they're being healthy enough to control the underlying problem. If I can keep them away from that dark pathway, I feel like I've done something good," Swaminath said.
Crohn's disease involves the immune system and is characterized by abdominal symptoms, such as pain and diarrhea, and chronic inflammation, according to the U.S. Centers for Disease Control and Prevention. Together with ulcerative colitis (another inflammatory bowel disease), it affects about 3 million people in the United States.
The study was conducted in 33 sites across the United States between September 2017 and October 2019. The study included 191 patients who were randomly assigned to one of the two diets, following it for 12 weeks. The participants received prepared food for the first six weeks.
The diets affected their symptoms, and at 12 weeks about 42.4% had symptomatic remission with SCD and 40.2% with the Mediterranean diet, according to the report.
The SCD includes unprocessed meats, fresh fruits, and non-starchy vegetables. It restricts certain legumes, all grains, certain sweeteners, canned fruits and vegetables, and certain dairy products. The Mediterranean diet is low in red and processed meats and features fresh fruits and vegetables, nuts, fish, lean meats, whole grains, small amounts of dairy and uses olive oil as its primary source of fat.
Diet isn't the only line of defense against Crohn's disease. For more than 20 years, since the first biologic medication was approved, there has been a blossoming of different medical therapies, Swaminath said. Prior to that, existing medications including steroids and immune modulators were repurposed to treat the disease.
"While admittedly, we haven't cured everybody or gotten everyone into a medicine-induced remission, we can help most people get to essentially a normal quality of life," Swaminath said.
Still, some people want an alternative to immunosuppressive therapy, according to the study, and high-quality data on diets for Crohn's disease is lacking.
Swaminath said that the people who were included in the study had mild to moderate disease. If someone is really sick and already malnourished, most physicians would not put them into a diet strategy, he added.
More than half the patients in the study were already taking a biologic medication, the researchers noted.
"What that means is, despite being on therapy, clearly they're on the therapy because it's working and they were better than they were before, but they still have symptoms that weren't cured," Swaminath said. "And if we can get half of those patients better by changing their diet or adopting one of these strategies, that really, I think, is valuable."
The findings were published online recently in the journal Gastroenterology.
Diet isn't a substitute for medication, but more of an adjunct, said Dr. Elie Abemayor, chief of the division of gastroenterology at Northern Westchester Hospital in Mount Kisco, N.Y. He was not involved in the study.
The two diets both try to reduce inflammation, but the Mediterranean diet is more palatable, he said.
When a patient is having more significant active inflammation, there's some belief that following a less inflammatory diet over the short term helps people and possibly lowers the likelihood of the patient progressing to a more significant inflammatory condition and disease, Abemayor said.
"I think that, in the short term, it is beneficial. I think longer term whether keeping people on Mediterranean diets or putting them on the SCD diet, I don't think that the jury's in on that yet, but I think probably in terms of general health it's probably a better diet for everybody to be on a Mediterranean-type diet," Abemayor said.
Some research is investigating whether the gut microbiome may play a role, Abemayor said, and whether people are more likely to respond to different kinds of treatment depending on their microbiome.
"I think that's where a lot of these treatments for gastrointestinal conditions are going to be headed, to stratify people based on genetics, based on maybe their microbiome, based on other kinds of things which separate one group from another," Abemayor said.