A recent study, published in the journal Nutrition, demonstrated the effect of broccoli and blueberries on bowel inflammation in an animal model of inflammatory bowel disease (IBD).1 Researchers fed IBD mice either a control diet, or a diet with 10 percent broccoli or ten percent blueberries. Both the broccoli- and blueberry-fed mice exhibited similar changes in gut microbiota with one exception: the broccoli-fed mice had lower levels of the bacteria Faecalibacterium prausnitzii. Both diets also increased the size of colon crypt cells and number of goblet cells per crypt. (Intestinal crypt cells are located in the “valleys” of the intestinal villi.)
Differences between the broccoli- and blueberry-fed mice were also observed. Higher concentrations of butyric acid and lower concentrations of succinic acid were found in the broccoli-fed mice; the only diet to reduce inflammation in the colon was the broccoli-fed diet; and broccoli-fed mice exhibited less translocation of microbes to mesenteric lymph nodes than the blueberry-fed or control mice. (This means in the broccoli-fed mice gut bacteria stayed in the gut rather than translocating through a leaky gut into gut-associated lymph nodes.)
One reason the blueberry-fed mice may not have had as beneficial an impact as the broccoli-fed mice could be the high fructose content of blueberries. Foods high in fructose can produce fermentation in the gut.2 Inflammatory bowel disease involves a gut sensitivity to the microbes residing there. Increased fermentation may further disrupt an already sensitive environment.
Blueberries have been found to benefit microbial metabolism in the colon, likely due to the anti-inflammatory effects of blueberry’s phenolic compounds.3 Broccoli is also well known for its protective effects in the large bowel, mostly attributed to the sulforophane and indole-3-carbinol (I3C) bioactives.4
This study is helping to prove that whole foods absolutely affect the microbial population. The moral of the story? Well, more studies need to be done to confirm the effects in humans, and to elucidate the mechanisms at work, but in the meantime, eat more broccoli! In fact, eat more vegetables (and fruits if you aren’t sensitive) in general. The thousands of phytochemicals found in vegetables and fruits have more beneficial effects in our guts—and our entire bodies—than we will ever know.
References
- G. Paturi, et al., “Influence of dietary blueberry and broccoli on cecal microbiota activity and colon morphology in mdr1a(-/-) mice, a model of inflammatory bowel diseases.” Nutrition. 2011 Nov 22. [Epub ahead of print]
- P.R. Gibson, et al., “Review article: fructose malabsorption and the bigger picture.” Aliment Pharmacol Ther. 2007 Feb 15;25(4):349-63.
- W.R. Russell, et al., “Availability of blueberry phenolics for microbial metabolism in the colon and the potential inflammatory implications.” Mol Nutr Food Res. 2007 Jun;51(6):726-31.
- E.H. Jeffrey and M. Araya, “Physiological effects of broccoli consumption.” Phytochem Rev. 2009;8:283-9.