Figure 4.

Multiple pathways for the delivery of dietary bioactives to colonocytes. (a) Blood pathway. Polyunsaturated fatty acids are delivered to colonocytes and other cell types, such as T cells, through the bloodstream after digestion and absorption from the small intestine into the portal vein. In the colonocyte, the fatty acids are incorporated into phospholipids in the plasma membrane. Abbreviation: DHA, docosahexaenoic acid. (b) Intestinal pathway. Curcumin is poorly bioavailable and hence is transported, intact, to the colon, where it can intercalate between phospholipids in the plasma membrane of colonocytes. (c) Microbial pathway. Pectin is not digestible by human enzymes and therefore transits to the colon, where gut microbes ferment it to produce butyrate, which is rapidly taken up by colonocytes.