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IBD anti-inflammatory diet creator and clinical trial co-investigator Barbara Olendzki is pictured in the kitchen where she holds cooking classes for participants. |
Inflammatory bowel disease patients interested in a diet that may relieve symptoms and reduce medications are taking part in a pilot clinical trial underway at UMass Medical School. Researchers are seeking to better understand how an anti-inflammatory diet, shown to be effective in alleviating symptoms, works by altering the bacteria that populate the intestinal microbiome.
“We are looking at the intersection of diet with microbial changes in the gut. Diet is one of the main influences on changes in the microbial community,” said Ana Maldonado-Contreras, PhD, instructor in microbiology & physiological systems and principal investigator for the study. “We’re trying to understand how our anti-inflammatory diet developed for treating and managing inflammatory bowel disease actually impacts bacterial communities, and if these microbial effects have any clinical implications in terms of symptoms getting better or not.”
Inflammatory bowel diseases, which include Crohn’s disease and ulcerative colitis, are chronic inflammatory conditions of the intestinal tract that can cause debilitating pain, bloating and diarrhea. Medications can alleviate symptoms, but are not cures and come with side effects.
Developed by co-investigator Barbara Olendzki, RD, MPH, the anti-inflammatory diet for IBD is a nutritional regimen that restricts the intake of complex carbohydrates such as refined sugar, gluten-based grains, and certain starches from the diet. These carbohydrates are thought to provide a substrate for proinflammatory bacteria. The diet also includes nutritious foods that are pre-and probiotics to help restore an anti-inflammatory environment. Participants are taught how to prepare the foods to enhance absorption and tolerance.
“We hypothesize that specific dietary modifications may significantly alter the intestinal microbiome and improve nutrient absorption, which in turn alters the immune response in such a way as to reduce disease activity and improve outcomes,”said Olendzki, associate professor of medicine in the Division of Preventive and Behavioral Medicine and director of the UMMS Center for Applied Nutrition. “We’re collaborating with the UMMS Center for Microbiome Research to determine the components of the diet that match with the changes in the microbiome, to work toward establishing evidence-based dietary guidelines for IBD patients, which currently don’t exist.”
Trial participants serve as their own controls, with a baseline assessment of their dietary intake, symptoms, inflammatory markers in the blood and analysis of their microbiota in stool samples conducted over the first four weeks. The dietary intervention takes place over the next 10 to 12 weeks, during which time participants receive extensive support for their dietary changes, including consultations with Olendzki and cooking classes that they can attend along with household members who cook and eat with them.
The clinical trial sprang from a small, retrospective case study of the diet, published in Nutrition Journal, in which all of the patients who adhered to the diet for at least four weeks experienced significant reduction in their symptoms, and were able to discontinue at least one of their IBD medications.
For the current trial, patients are provided with stool sample collection kits with DNA-preserving test tubes. Blood samples are taken at the beginning and the end of the study to compare inflammatory markers before and after the diet intervention. A novel component of the study is looking critically at dietary patterns, with patients completing a food frequency questionnaire via a web-based tool three times a week.
“Even when microbial communities in the gut at baseline are very variable, we can see that those following the diet have similar changes in the microbiota ” said Dr. Maldonado-Contreras. “The bacteria that are decreasing and increasing after the diet are the same. We are also seeing an increase in the overall diversity of the microbial communities in the gut in patients following the diet, and diversity is important for intestinal health.”
Other diet modifications being explored for IBD tend to be narrow and supplement driven. In contrast, the UMMS study is taking a different approach. “We’re trying to show that something that’s achievable as a lifestyle change makes a physiological change that we can assess in the microbiome of disease,” said co-investigator Doyle Ward, PhD, associate professor of microbiology & physiological systems.
The Ward lab in the UMMS Center for Microbiome Research provides the scientific infrastructure needed to analyze microbial changes in trial participants’ stool samples. “We can now support the successful observations of the diet intervention with the science it’s supposed to be affecting,” said Dr. Ward. “A lot of predictions about the diet are proving to be true: when you adjust the diet, the microbiome changes in ways that reduce the number of potentially bad, inflammatory bacteria and increase the presence of good bacteria.”
Related stories on UMassMedNow:
Maldonado-Contreras recognized by American Gastroenterological Association for gut microbiome research
Searching the microbiome for clues to managing inflammatory bowel disease
UMMS first to develop evidence-based diet for inflammatory bowel disease
