Because c9,t11 CLA occurs in commercial supplements as well as in the diet, the present results should be confirmed in larger studies that also include women. There were no differences between groups in body composition.Ī CLA preparation containing the purified c9,t11 CLA isomer increased insulin resistance and lipid peroxidation compared with placebo in obese men. The decreased insulin sensitivity was independent of changes in serum lipids, glycemia, body mass index, and body fat but was abolished after adjustment for changes in 8-iso-prostaglandin F(2alpha) concentrations. Compared with placebo, c9,t11 CLA decreased insulin sensitivity by 15% (P < 0.05) and increased 8-iso-prostaglandin F(2alpha) and 15-keto-dihydro-prostaglandin F(2alpha) excretion by 50% (P < 0.01) and 15% (P < 0.05), respectively. Before and after 3 mo of supplementation, we assessed insulin sensitivity (hyperinsulinemic euglycemic clamp), lipid metabolism, body composition, and urinary 8-iso-prostaglandin F(2alpha) (a major F(2)-isoprostane) and 15-keto-dihydro-prostaglandin F(2alpha), markers of in vivo oxidative stress and inflammation, respectively.Īll subjects completed the study. In a randomized, double-blind, placebo-controlled study, 25 abdominally obese men received 3 g c9,t11 CLA/d or placebo (olive oil). We investigated the effects of c9,t11 CLA supplementation on insulin sensitivity, body composition, and lipid peroxidation in a group at high risk for cardiovascular disease. Because c9,t11 CLA is the predominant CLA isomer in foods and is included in dietary weight-loss products, it is important to conduct randomized controlled studies that use c9,t11 CLA preparations. However, metabolic effects of the c9,t11 CLA isomer are still unknown in obese men. 37:75–81 (1989).We recently showed that trans-10,cis-12 (t10,c12) conjugated linoleic acid (CLA) causes insulin resistance in obese men. Pariza, Newly Recognized Anticarcinogenic Fatty Acids: Identification and Quantification in Natural and Processed Cheese, J. Hopkins, C.Y., Fatty Acids with Conjugated Unsaturation, Topics in Lipid Chemistry, edited by F.D. Vouros, Gas Chromatography-Mass Spectrometry of Conjugated Dienes by Derivatization with 4-Methyl-1,2,4-Triazoline-3,5-Dione, J.
Pfeilsticker, Electron Impact Mass Spectra of Some Conjugated Diene and Triene C 18 Fatty Acids, J. de Buyck, An Efficient Countercurrent Distribution Method for the Large-Scale Isolation of Dimorphecolic Acid Methyl Ester, Chem. Scrimgeour, Synthesis, Characterisation, and Transformation of a Lipid Cyclic Peroxide, J. Christie, Structural Analysis of Fatty Acids by Mass Spectrometry of Picolinyl Esters and Dimethyl-oxazoline Derivatives, Trends Anal. 2-Alkenyl-4,4-Dimethyloxalines as Derivatives for the Double Bond Location of Long-Chain Olefinic Acids, Biomed. Huang, Chemical Modification in Mass Spectrometry IV. Sprecher, 2-Alkenyl-4,4-Dimethyloxazolines Derivatives for the Structural Elucidation of Isomeric Unsaturated Fatty Acids, Lipids 28:561–564 (1993). Richli, Localisation of Double Bond in Polyunsaturated Fatty Acids by Gas Chromatography-Mass Spectrometry After 4,4-Dimethyloxzoline Derivatisation, J. Said, Methyl 12-Mesyloxyoleate as a Source of Cyclopropane Esters and of Conjugated Octadecadienoates, Chem. Lombardi, Liquid Chromatographic-Mass Spectrometric Analysis of Conjugated Diene Fatty Acids in a Partially Hydrogenated Fat, J. Dormandy, The Nature of Diene Conjugation in Human Serum. However, the cis-9,trans-11 and trans-10,cis-12 CLA isomers significantly decreased SCD protein levels and SCD activity in MDA-MB-231 cells. Pariza, Conjugated Linoleic Acid (9,11- and 10,12-Octadecadienoic Acid) Is Produced in Conventional But Not Germ-Free Rats Fed Linoleic Acid. Treatment of the cells with the cis-9,trans-11 and trans-10,cis-12 CLA isomers (45 microM) did not repress SCD mRNA in both MDA-MB-231 and MCF-7 cells. Tove, Biohydrogenation of Unsaturated Fatty Acids: Purification and Properties of cis-9, trans-11 Octadecadienoate Reductase, Ibid.:3643–3649 (1982).Ĭhin, S.F., J.M. Tove, Biohydrogenation of Unsaturated Fatty Acids, J. Pariza, Conjugated Linoleic Acid and Atherosclerosis in Rabbits, Atherosclerosis 108:19–25 (1994). Huth, Effect of Feeding Diets Enriched in Conjugated Linoleic Acid on Lipoproteins and Aortic Atherogenesis in Hamsters, Circulation 88:Suppl. A Powerful Anticarcinogen from Animal Fat Sources, Cancer Suppl. Pariza, Mammary Cancer Prevention by Conjugated Dienoic Derivatives of Linoleic Acid, Ibid.:6118–6124 (1991). Pariza, Inhibition of Benzo(a)pyrene-Induced Mouse Forestomach Neoplasia by Conjugated Dienoic Derivatives of Linoleic Acid, Cancer Res.