Dietary therapy: Eating the right foods can help modulate IBD

The gut bacteria are crucial to health and the variable that links inflammatory bowel disease (IBD) to diet. What people eat shapes the composition of bugs that live in the gut, and an imbalance in this composition can promote a range of medical conditions, including IBD. It follows that diet may be involved in the development of IBD, and that diet may be a potential therapy, according to an expert.

“We know that diet is important to our IBD patients, so one of the first questions that patients and parents ask us is what to eat. Many patients follow, in essence, their own exclusion diet based on the belief that certain foods worsen symptoms or may trigger disease exacerbations,” Dr Lindsey Albenberg, of Perelman School of Medicine at The University of Pennsylvania in the US, said at the Advances in Inflammatory Bowel Diseases Annual Conference 2021.

In one study that described patients’ perceptions regarding the benefits and harms of selected foods, patients felt that yogurt and rice, among others, improved symptoms. Bananas, meanwhile, were associated with better symptoms in patients with ulcerated colitis with a pouch. Conversely, a whole host of foods were felt to worsen symptoms, and these were generally consistent among IBD types. [Dig Dis Sci 2013;58:1322-1328]

“Not surprisingly, patients tended to avoid foods that they reported as worsening their symptoms, but it's important to recognize that worsening of symptoms does not necessarily equal worsening of inflammation, and vice versa,” Albenberg pointed out.

Some foods make people sick

Indeed, certain dietary patterns may predispose to the development of IBD. Albenberg cited a recent study that looked at the inflammatory potential of diets by calculating an empiric dietary inflammatory pattern (EDIP) score, a weighted sum of 18 food groups with a higher sum correlating with a more proinflammatory diet. 

Over 4,000,000 person-years of follow-up, there were about 300 incident cases of Crohn's disease and about 400 incident cases of all ulcerative colitis recorded. The highest quartile of EDIP score conferred a 51-percent increase in the risk of developing Crohn's disease, while there were no associations seen for ulcerative colitis. [Gastroenterology 2020;159:873-883.e1]

Clearly, there is something bad in our diet that, through alterations in the microbiome or other effects on gut barrier function, may promote IBD, Albenberg noted.

Several studies pin the blame on Western diet, which is sugary, fat-laden, and ubiquitous in processed foods. Mass-produced foods that contain additives like emulsifiers, preservatives, extra sweeteners, and flavourings have been linked to the development of IBD. These data suggest that the Western diet may well be an environmental trigger for the disease. [BMJ 2021;374:n1554; Clin Gastroenterol Hepatol 2021;doi:10.1016/j.cgh.2021.08.031]

Dietary interventions in IBD

In the management of IBD, there are two goals considered; one is to induce remission, and the other is to reduce inflammation. Exclusive enteral nutritional therapy or defined formula diets as well as whole food-based therapeutic diets have been shown to be beneficial in this regard.

“So the dietary therapy that we're all the most familiar with is exclusive enteral nutrition (EEN) for the treatment of Crohn's disease,” Albenberg said.

EEN is a potent treatment and as good as corticosteroids at inducing remission in paediatric Crohn’s disease. A previous meta-analysis reported that children who received EEN were even more likely to achieve intestinal healing compared with those who were on corticosteroids. [Aliment Pharmacol Ther 2017;46:645-656]

Albenberg shared that at their centre, she and other physicians commonly recommend modified EEN for their paediatric Crohn's disease patients to allow some flexibility in the diet, which improved acceptance according to anecdotal evidence.

With the goal of inducing remission over 8 to 12 weeks, “what we do is we calculate calorie needs using the WHOREE equation. And we multiply this by an activity factor that's specific to the patient, and then we provide 80–90 percent of these needs from formula. And really, any formula is okay,” she said.

The modified partial enteral nutrition protocol, according to Albenberg, incorporates the Japanese and the Mediterranean style diets for the whole food portion. This is in line with IBD dietary guidelines that recommend increasing intake of fruits, veggies, and omega 3, as well as minimizing consumption of processed foods. 

When it comes to whole food-based therapeutic diets, an exclusion diet low in carbohydrates and processed foods, namely the specific carbohydrate diet (SCD), has been advocated for both ulcerative colitis and Crohn's disease, Albenberg said. “It was actually developed in the early 1920s for the treatment of celiac [disease] and then found its way as a diet therapy for the IBD population.”

In one study that evaluated a 12-week intervention with SCD vs a Mediterranean diet for adults with Crohn’s disease, there were improvements in disease activity and patient-reported outcomes, such as quality of life, fatigue, pain, interference, sleep disturbance, and social isolation in both arms with no between-group differences. SCD was not superior to the Mediterranean diet to achieve symptomatic remission at week 6 and at week 12. [Gastroenterology 2021;161:837-852.e9]

“And so I think that take home points here are that Mediterranean diet may actually be quite good for some of our patients. It's less restrictive and has well documented general health benefits, and it might be a great option to improve symptoms in our patients,” Albenberg said.

There are limitations to the clinical data for dietary therapy in IBD, Albenberg acknowledged, but this should not necessarily be a deterrent. “Shared decision making and following objective outcomes closely are critical.”

She believes that dietary therapy should be considered “a drug,” such that physicians should expect the same compliance with therapy and monitoring and should be willing to move on if therapy is not working.