Gut bacteria are required for the benefits of black raspberries in mice.

BACKGROUND

The gut microbiota plays a pivotal role in the development of inflammatory bowel disease and colorectal cancer.

OBJECTIVE

To determine whether the gut microbiota is required for the chemoprotective effects of black raspberries (BRBs) in mice.

METHODS

mice were given (a) a control diet for 8 weeks, or (b) the control diet for 4 weeks and then a 5% BRB diet for additional 4 weeks, or (c) the control diet and antibiotics for 4 weeks followed by the 5% BRB diet and antibiotics for the next 4 weeks. At the end of the study, all the mice were euthanized, and colonic and intestinal polyps were counted. mRNA expression levels of and were determined in colon and small intestine of these mice by quantitative real-time PCR.

RESULTS

5% BRBs significantly suppressed intestinal and colonic polyp development in the mice, whereas antibiotics significantly abolished BRBs' chemoprotective effects. BRBs decreased mRNA levels of and in colon, whereas significantly enhanced mRNA levels of and were observed in small intestine of BRB-treated mice fed antibiotics.

CONCLUSIONS

The gut microbiota is required for BRBs' chemoprotection against polyp development in mice.