Dried Plums Modify Colon Microbiota Composition And Spatial Distribution, And Protect Against Chemically‐Induced Carcinogenesis

Abstract

Differences in microbial populations in the proximal and distal colon may impact apparent site‐specific differences in pathology. Diet is known to alter metabolism and composition of colon microbiota, which has major implications for disease prevention and treatment. The hypothesis tested by this experiment was that consumption of dried plums would promote retention of beneficial microbiota and patterns of microbial metabolism throughout the colon, and that by doing so would reduce colon cancer incidence. Male Sprague‐Dawley rats were provided either a control (CD, n=25) or plum diet (PD, 5% of calories, n=26) 3 wk before being given two injections of AOM (15 mg/kg BW) or saline, and sacrificed 8 wk later. Tissues were resected and fecal contents isolated separately from the proximal and distal colon. Irrespective of treatment, the PD increased Bacteroidetes (p<0.0001) and reduced Firmicutes (p<0.0001) in the distal colon without affecting their proximal proportions, compared to the CD, which suppressed Bacteroidetes and increased Firmicutes in the distal colon. Additionally, rats consuming PD had significantly reduced numbers of aberrant crypts (p=0.0025), aberrant crypt foci (p=0.0060), and high multiplicity aberrant crypt foci (p=0.0008) compared to CD rats. These data support our hypothesis that dried plums protect against colon cancer, and this may be due in part to their ability to establish putatively beneficial colon microbiota compositions in the distal colon. Supported by California Dried Plum Board PN 12‐20.