Metabolism of flavanols (catechins, procyanidins) by gut microbiota has been extensively characterized. Comparatively little is known about accumulation of flavanols and their metabolites in the colon tissues, particularly during chronic exposure to low doses. Mice were fed low doses of cocoa flavanols for 12 weeks. Supplementation of the control diet with flavanols did not increase colonic tissue accumulation of flavanols nor microbial metabolites versus control. The type of cocoa flavanols did not affect colonic tissue accumulation of native flavanols or metabolites. Total phenolic content of the diets indicated that these results are not explained by background levels of undetected phenolics in the control diet. This is the longest known chronic flavanol feeding study to examine colonic tissue accumulation. Vast differences appear to exist between acute high doses and chronic low doses, to which gut microbiota and epithelium adapt. These results indicate that the fate of flavanols in the colon during chronic exposure is not fully understood.
Keywords: catechins; cocoa; colon; degree of polymerization; flavanols; metabolites; microflora; procyanidins.