a1 Unit of Pharmacokinetics, Metabolism, Nutrition and Toxicology, Department of Pharmaceutical Sciences, Université Catholique de Louvain, B-1200 Brussels, Belgium
The hypothesis tested in the present study is that dietary fructans are able to modulate gastrointestinal peptides involved in the control of food intake, namely glucagon-like peptide (GLP)-1 (7-36) amide and ghrelin. After 3 weeks of treatment with a standard diet (control) or the same diet enriched with 100 g fructans varying in their degrees of polymerization (oligofructose (OFS), Synergy 1 (Syn) or long chain inulin)/kg, male Wistar rats were deprived of food for 8 h before sample collection. Dietary energy intake throughout the experiment was significantly lower (P>0·05) in fructans-fed rats than in control rats, leading to a significant decrease (P>0·01) in epidydimal fat mass at the end of the treatment in OFS- and Syn-treated rats. GLP-1 (7-36) amide concentration in portal vein serum was higher in OFS- and Syn-fed than in control rats. Both GLP-1 (7-36) amide concentration and proglucagon mRNA concentrations were significantly greater (P>0·05) in the proximal colonic mucosa of fructans-fed rats v. controls. Normally active ghrelin concentration in plasma increases during food deprivation and rapidly falls during a meal. In the present study, after 8 h of food deprivation, active ghrelin in the plasma remained significantly lower (P>0·05) in OFS and Syn-fed than in control rats. These results are in accordance with the modifications of dietary intake and fat-mass development in short-chain fructans-treated rats and demonstrate the potential modulation of GLP-1 (7-36) amide and ghrelin by fermentable fibres such as fructans, which are rapidly and extensively fermented in the proximal part of the colon.
(Received February 20 2004)
(Revised April 29 2004)
(Accepted May 17 2004)
* Results presented (oral communication) in part at the 9th European Nutrition Confernce, 1–4 Ocotber 2003, Rome, Italy, and at the American Diabetes Association Research Symposium, 9–12 December 2003, Long Beach, LA, USA.