Submitted to: BioMed Central (BMC) Gastroenterology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/16/2009
Publication Date: 9/16/2009
Citation: Simmen, F.A., Frank, J.A., Wu, X., Xiao, R., Hennings, L.J., Prior, R.L. 2009. Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intenstions and colon. BioMed Central (BMC) Gastroenterology. 9(1):67-76. Interpretive Summary: Addition of berries to the human diet may provide health benefits. Several previous studies have suggested that berry consumption may protect against onset and development of cancers in animals and perhaps humans. In this study, we tested whether addition of blueberry to the diet using a standard rat model of colon cancer, was effective in preventing colon cancer. We observed that feeding blueberries in dried powered form resulted in fewer numbers of rats with intestine cancers, but this effect was mainly observed in male rats. Protective effects of blueberry in female rats were more subtle and appeared to have a different basis than for males. Overall, results were encouraging regarding the cancer-inhibitory potential of blueberry supplemented diets in rats and by inference humans.
Technical Abstract: We examined the efficacy of freeze-dried blueberry (BB) in inhibition of formation of azoxymethane (AOM)-induced colon aberrant crypt foci (ACF) and intestine tumors in male and female Sprague-Dawley rats. Pregnant rats were fed a control diet with or without 10% BB; progeny were weaned to the same diet as their dam. Small intestines and colons were obtained from progeny at 6 weeks (for determination of ACF) and 17 weeks (for tumor analysis) after AOM administration. BB consumption resulted in fewer ACF in the mid and distal colon of male rats; with a tendency (0.1 > P > 0.05) for a approximately 24% reduction in total number of ACF. By contrast, BB elevated ACF numbers (approximately 30%, 0.1 > P > 0.05) in the colon of female rats. There were fewer adenocarcinomas, as a proportion of total tumor number, in colons (0.1 > P > 0.05) and small intestines (P < 0.05) of female than male rats. In males, BB favored a reduction in tumor (adenoma + adenocarcinoma) incidence (0.1 > P > 0.05) for small intestine + colon. Tumor incidence in female rats was unaffected by BB. In small intestines of females, BB resulted in fewer adenocarcinomas and more adenomas (P < 0.05) compared to control diet. We conclude that blueberry inhibits AOM-induced intestine cancers in rats in gender- and tissue subsite-specific fashion.