Full Papers

Trans-10, cis-12-conjugated linoleic acid does not increase body fat loss induced by energy restriction

Arrate Lasa^a1, Itziar Churruca^a1, Edurne Simón^a1, Alfredo Fernández-Quintela^a1, Victor Manuel Rodríguez^a1 and María Puy Portillo^a1 c1

^a1 Department of Nutrition and Food Science, University of País Vasco, Paseo de la Universidad 7, 01006 Vitoria, Spain

Abstract

Very little evidence exists concerning the effects of conjugated linoleic acid (CLA) on body fat reduction induced by energy restriction. Moreover, although an effect of trans-10, cis-12-CLA on lipolysis has been suggested, it has not been consistently shown. The aims of the present study were to determine whether trans-10, cis-12-CLA increases the reduction of body fat induced by energy restriction, and to analyse its effect on lipolysis and adipose tissue lipase expression (hormone-sensitive lipase (HSL) and adipose tissue TAG lipase (ATGL)). Male Syrian Golden hamsters were fed a high-fat diet during 7 weeks in order to make them fatter. Then they were submitted to a mild energy restriction (25 %) without or with supplementation of 0·5 % trans-10, cis-12-CLA for 3 weeks. Basal glycerol release and lipolysis stimulated by several drugs acting at different levels of the lipolytic cascade were measured in epididymal adipose tissue. The expression of HSL and ATGL was assessed by real-time RT-PCR. No differences were found in adipose tissues size between the experimental groups. Medium adipocyte size and total number of adipocytes were similar in both experimental groups. Animals fed the CLA-enriched diet showed similar lipolytic rates as well as HSL and ATGL expressions to the controls. In conclusion, trans-10, cis-12-CLA does not promote adipose tissue lipid mobilisation nor does it heighten body fat reduction induced by energy restriction. Consequently, this CLA isomer does not seem to be a useful tool to be included in body weight-loss strategies followed in obesity treatment.

(Received January 17 2008)

(Revised March 18 2008)

(Accepted April 16 2008)

(Online publication May 29 2008)

Key Words:

• Conjugated linoleic acid;
• Lipolysis;
• Energy restriction;
• Hamsters

Correspondence:

^c1 Corresponding author: Dr María P. Portillo, fax +34 945 013014, email mariapuy.portillo@ehu.es

Footnotes

Abbreviations: ATGL, adipose tissue TAG lipase; CLA, conjugated linoleic acid; HSL, hormone-sensitive lipase; RC, restricted group fed a control diet; RCLA, restricted group fed a CLA-supplemented diet