High-fiber foods, such as 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 on mice. The study was published mSystemsA Journal of the American Society for Microbiology.
In the study, the investigators 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, the microbes involved in Crohn’s. in the gut, and how those microbes will use an inactive compound in broccoli sprouts to produce an anti-inflammatory compound in the gut. They also wanted to determine whether a diet containing broccoli sprouts alleviates Crohn’s symptoms, due to the anti-inflammatory metabolites naturally present in the sprouts.
The researchers used 4 groups of IL-10-KO mice in the study. In the first round, they enrolled mice at 4 weeks of age who ate their standard mouse tea the entire time, as well as mice who ate mouse tea mixed with raw broccoli sprouts. In the second round, they had the same 2 diet groups, but mice were enrolled at 7 weeks of age. The researchers were particularly interested in understanding the development of IBD early in life, which is why they studied mouse models of Crohn’s with hope for the juvenile (4-6 weeks old) and adolescent (7-9 weeks old) stages. Better understand host-diet-microbial community interactions and how disease severity differs by age.
The researchers fed the mice for 7 days to acclimate them to their respective diets before symptoms began, and the mice remained on their diets for the following 2 weeks during disease progression. To trigger symptoms, new healthy mice that host more microbes were added to the cage. Because the IL-10-KO mice in the study cannot produce IL-10, their immune systems have trouble tolerating the gut microbiota, and the new microbes in the cage trigger colitis and Crohn’s symptoms. For 15-16 days following infection, the researchers regularly weighed the mice and collected stool samples to assess signs of developing colitis.
At the end of the study, the researchers examined the intestinal tissue of the euthanized mice and the microbial communities present throughout their intestines, as well as the presence of specific markers of inflammation and broccoli metabolism in the blood. The researchers wanted to know what kind of microbes live in certain parts of the gut. In other words, they wanted to understand how a broccoli sprout diet affects microbial biogeography in Crohn’s models, since they couldn’t study it in humans.
DNA was extracted from intestinal tissue samples collected from mice and sent for sequencing to identify the bacteria present. Once the sequencing data was returned, the researchers used bioinformatics software and human intelligence to study the gut microbial ecology of our mouse models.
We have many exciting results from this research. First, we show that rats that ate a broccoli sprout diet had higher blood concentrations of an anti-inflammatory metabolite called sulforaphane. Although our mice were immunocompromised and had colitis, this increase in sulforaphane protected them from severe disease symptoms such as weight loss, blood in the stool, and diarrhea.”
Lola Holcomb, lead author and PhD candidate in the Graduate School of Biomedical Sciences and Engineering at the University of Maine
Lola Suzanne Isaac, Ph.D. It is led by a lab member, a corresponding study author and assistant professor of animal and veterinary science at the University of Maine, School of Food and Agriculture, Orono, Maine.
Importantly, the researchers found that the younger group of mice, the juveniles, responded better to the broccoli sprout diet than their adolescent counterparts. Young mice had milder disease symptoms and richer gut microbial communities. Moreover, smaller mice show stronger bacterial community similarity to each other (aka, stronger beta-diversity) and stronger adherence to location-specific community composition across different parts of the gut.
“Simply put, we found that of the 4 groups we studied, the young mice fed the broccoli sprout diet had the mildest disease symptoms and the strongest gut microbiota,” Holcomb said.
Researchers say that broccoli sprouts, which are easy to grow and available in grocery stores, could be used as a treatment strategy for IBD patients.