HUMAN RECTAL ABSORPTION OF SHORT-CHAIN AND MEDIUM-CHAIN C-2-C-10 FATTY-ACIDS

Background: Current knowledge on the colonorectal absorption of medium -chain fatty acids is limited. The purpose of the present study was to evaluate and compare the human rectal absorption of short-and medium- chain C-2-C-10 fatty acids in healthy volunteers. Methods: Dialysis ba gs containing 20 mmol.l(-1) of the fatty acids acetate, butyrate, hexa noate, octanoate, or decanoate in a phosphate-buffered (pH neutral) is oosmotic electrolyte solution were placed in the rectum for 30 min in 14 healthy volunteers. Absorption rates were calculated for all fatty acids, sodium, potassium, and water. Results: Absorption rates of the fatty acids acetate, butyrate, hexanoate, octanoate or decanoate were the same (1.9 +/- 0.1 = 2.5 +/- 0.2 = 1.7 +/- 0.2 = 1.9 +/- 0.2 = 2.2 +/- 0.1 mu mol.cm(-1).h(-1) (mean +/- standard error of the mean), res pectively; P=0.24). Conclusions: Medium-chain fatty acids were absorbe d in the human rectum at a rate similar to that for short-chain fatty acids. If results can be applied to the human colon, colonic absorptio n of medium-chain fatty acids could possibly became an important secon dary site of absorption in abnormal intestinal conditions such as mass ive small-intestinal resection or malabsorption syndromes.