a1 Centre de Recherche en Nutrition Humaine de Lyon, Université Claude Bernard Lyon 1; INSERM U449; INRA 1235; Hospices Civils de Lyon, Place D'Arsonval, 69003 Lyon, France
a2 Danone Vitapole, RD 128, 91767 Palaiseau, France
Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. The present study was designed to determine whether 14-week CLA supplementation as triacylglycerols (3·76 g) with a 50 : 50 combination of the two main isomers (35 % cis-9, trans-11 and 35 % trans-10, cis-12) added to flavoured yoghurt-like products was able to alter body composition in healthy subjects and to alter the expression of several key adipose tissue genes (PPAR γ, lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and uncoupling protein 2 (UCP-2)). Forty-four healthy subjects were randomly assigned to consume daily either a CLA-supplemented yoghurt-like product or a placebo yoghurt for 98 d. There were no significant effects of CLA supplementation on body weight, fat mass or free fat mass. Basal energy expenditure expressed as kg free fat mass increased significantly in the CLA group (123·3 (sem 2·5) kJ/kg free fat mass per d on day 98 v. 118·7 (sem 2·3) kJ/kg free fat mass per d on day 0, P = 0·03). PPAR γ mRNA gene expression increased significantly with CLA supplementation (53 (sem 20) %, P < 0·01) and a significant reduction in mRNA levels of HSL was observed ( − 42 (sem 7) %, P = 0·01). The levels of UCP-2 and LPL mRNA were not affected. The present results suggest that a 98 d supplementation diet with a 50 : 50 mixture of the two CLA isomers cis-9, trans-11 and trans-10, cis-12 in a dairy product was unable to alter body composition, although a significant increase in the RMR has been induced. Moreover, changes in mRNA PPAR γ and HSL in adipose tissue were recorded.
(Received January 13 2006)
(Revised June 28 2006)
(Accepted June 28 2006)
Abbreviations: CLA, conjugated linoleic acid; HSL, hormone-sensitive lipase; LPL, lipoprotein lipase; UCP-2, uncoupling protein 2