Original Article Acetogenic fibers reduce fasting glucose turnover but not peripheral insulin resistance in metabolic syndrome patients Etienne Pouteau a, * , Véronique Ferchaud-Roucher b , Yassine Zair b , Morine Paintin a , Marc Enslen a , Nicolas Auriou a , Katherine Macé a , Jean-Philippe Godin a , Olivier Ballèvre c , Michel Krempf b a Nestlé Research Centre, P.O. Box 44, Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland b CRNH, Inserm U539, Hôtel-Dieu, Place Alexis Ricordeau, 44093 Nantes Cedex 01, France c Nestlé R&D, No. 5 DiJin Road, Haidian District, 100095 Beijing, China article info Article history: Received 6 January 2010 Accepted 25 May 2010 Keywords: Soluble fiber Acetate Glucose turnover Metabolic syndrome Insulin sensitivity summary Background & aims: The acute ingestion of an acetogenic indigestible carbohydrate (lactulose) increased acetate turnover associated with decreased lipolysis (glycerol turnover) in insulin-resistant patients. It is not known whether a decreased lipolysis by chronic ingestion of acetogenic indigestible carbohydrates or fibers improves glucose turnover and insulin sensitivity. Methods: Twenty-one men with metabolic syndrome ingested daily standardized drinks, with or without 28 g acetogenic fibers (acacia gum and pectin), for 5 weeks in a randomized double-blind crossover controlled study design. Euglycaemic-hyperinsulinaemic (EH) clamps coupled with kinetic studies were performed in the fasting state after treatments. Results: Flatulence was more frequent with fiber treatment. Body weight, lipids as well as acetate and glycerol turnovers were unchanged. Fasting endogenous glucose turnover was improved after fiber treatment (7.9  1.3 mmol kg 1 min 1 ) compared with control (8.6  1.6 mmol kg 1 min 1 , P < 0.05). But insulin sensitivity (glucose infusion rate) during the EH clamp was not different at the end of fiber and control treatments, 3.7  1.8 and 3.8  1.5 mg kg 1 min 1 , respectively, nor fasting plasma glucose and insulin. Conclusions: The chronic ingestion of acacia gum and pectin fibers did not decrease lipolysis but improved fasting endogenous glucose turnover with no effect on peripheral insulin resistance in metabolic syndrome patients. Ó 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. 1. Introduction During the last decades, the number of obese individuals and patients with metabolic disorders has dramatically increased worldwide. The metabolic syndrome is primarily defined as a central abdominal obesity associated with hypertriglyceridemia, reduced HDL-cholesterol, elevated blood pressure and/or raised glycemia. Central abdominal obesity is governed by an excess of fat and is generally associated with insulin resistance that suppresses normal insulin-inhibition of free fatty acids (FFA) release from adipose tissues into the blood circulation. Obese insulin-resistant individuals have higher plasma FFA concentrations that induce lipotoxicity associated with reduced insulin production by the pancreas and insulin action in peripheral and hepatic tissues. As a consequence, glucose concentrations rise over time, which favors the development of metabolic disorders and type 2 diabetes mellitus. 1e3 One of the strategies for the treatment of type 2 dia- betes mellitus is to inhibit lipolysis and reduce plasma FFA concentrations in order to diminish the development of insulin resistance. 4 Acipimox, a nicotinic acid like drug, was used as an anti-lipolytic agent to reduce dyslipidemia, for diabetes treatment. It successfully lowered plasma FFA concentrations which were accompanied by a beneficial decrease in peripheral insulin resis- tance in short-term studies. 4,5 Interestingly, previous nutritional studies indicated that acute alcohol intake has anti-lipolytic prop- erties which decrease plasma FFA concentrations. 6 Acetate, one of the metabolites of alcohol degradation, has been shown to directly reduce plasma FFA concentrations when it was infused intrave- nously into humans. 6 Colonic fermentation of dietary fibers yields large amounts of acetate which bypass the liver and reaches the peripheral blood circulation. 7 Our working hypothesis was there- fore that a nutritional intervention with dietary fiber would (i) enhance acetate concentrations in the systemic circulation, which * Corresponding author. Tel.: þ41 21 785 88 30; fax: þ41 21 785 85 44. E-mail address: etienne.pouteau@rdls.nestle.com (E. Pouteau). Contents lists available at ScienceDirect Clinical Nutrition journal homepage: http://www.elsevier.com/locate/clnu 0261-5614/$ e see front matter Ó 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. doi:10.1016/j.clnu.2010.05.006 Clinical Nutrition 29 (2010) 801e807