New York, Nov 11: High fibre diets, like those that include broccoli sprouts or other cruciferous vegetables, may reduce disease symptoms and improve quality of life in patients with inflammatory bowel disease (IBD), according to a study conducted in mice.
In the study, published in the journal mSystems, the researchers used a popular interleukin-10-knockout (IL-10-KO) mouse model of Crohn's to investigate the interactions between mice and their immune systems, as well as the broccoli sprout diet, microbes within the Crohn's-afflicted gut, and how those microbes would use an inactive compound in the broccoli sprouts to make an anti-inflammatory compound in the gut.
The researchers from the University of Maine used four groups of IL-10-KO mice in the study.
In the first round, they had younger mice enrolled at four weeks of age who ate their standard mouse chow the whole time, as well as mice who ate the mouse chow with raw broccoli sprouts mixed in.
In the second round, they had the same two diet groups, but mice were enrolled at seven weeks of age.
The mice were fed for seven days to acclimate to their respective diets before the researchers triggered symptoms, and the mice stayed on their diets for the following two weeks while the disease progressed.
To trigger symptoms, new healthy mice that host more microbes were added to the cage.
Since the IL-10-KO mice in the study can't produce IL-10, their immune systems have trouble tolerating gut microbiota , and the new microbes in the cage triggered colitis and Crohn's symptoms.
At the end of the study, the researchers examined the gut tissues of the euthanised mice and microbial communities present throughout their intestines, as well as the presence of certain markers of inflammation and broccoli metabolites in the blood.
"We found many exciting results from this study. First, we show that the mice that ate the broccoli sprout diet had a greater concentration of an anti-inflammatory metabolite called sulforaphane in their blood," said lead author Lola Holcomb, doctoral candidate in the Graduate School of Biomedical Sciences and Engineering at the University of Maine.
"Even though our mice were immunocompromised and had colitis, this increase in sulforaphane protected them from severe disease symptoms like weight loss , faecal blood and diarrhoea," Holcomb added.
Interestingly, the researchers found that the younger group of mice, the juveniles, responded better to the broccoli sprout diet than their adolescent counterparts did. The younger mice had milder disease symptoms and richer gut microbial communities.
Furthermore, the younger mice showed stronger bacterial community similarity to each other (aka, stronger beta-diversity), and stronger adherence to location-specific community composition throughout different parts of the gut.
"Simply put, we found that of the four groups we studied, the younger mice fed a broccoli sprout diet had the mildest disease symptoms and the most robust gut microbiota," Holcomb said.
The researchers say that broccoli sprouts, which are easily grown and found in grocery stores, could be used as a treatment strategy for patients with IBD.