Dietary fructans and lipid metabolism : building a bridge from the colon to the liver

Abstract

Several non digestible but fermentable dietary carbohydrates, besides their effect on the gastrointestinal tract, are also able to exert systemic effect, namely by modifying the metabolism of lipids. The present review aims at illustrating how specific fermentable carbohydrates, namely dietary fructans, escaping the hydrolysis by amylases or disaccharidases, highly fermented in the caeco-colon by gramnegative bacteria, are susceptible to influence fatty acid metabolism and lipemia in experimental animal models, but also in humans. By focusing on the effect of oligofructose or inulin, which are dietary fructans obtained from chicorey roots, we illustrate here that the hepatic metabolism of fatty acids seems to be a relevant goal of fructans. The panel of the putative mediators of the systemic effects of fructans are presented and discussed, and consist in either 1) modifications in glucose/insulin homeostasis 2) the end-products of colonic fermentation of fructans, reaching the liver by the portal vein and /or 3) intestinal hormones and /or 4) other nutrients availability