Trans-11 Vaccenic Acid Dietary Supplementation Induces Hypolipidemic Effects in JCR:LA-cp Rats

Trans-11 vaccenic acid [VA; 18:1(n-9)] is a positional and geometric isomer of oleic acid and is the precursor to conjugated linoleic acid (CLA) in humans. Despite VA being the predominant trans monoene in ruminant-derived lipids, very little is known about its nutritional bioactivity, particularly in conditions of chronic metabolic disorders, including obesity, insulin resistance, and/or dyslipidemia. The aim of this study was to assess the potential of VA to improve dyslipidemia, insulin sensitivity, or inflammatory status in obese and insulin-resistant JCR:LA-cp rats. The obese rats and age-matched lean littermates were fed a control diet or a control diet supplemented with 1.5% (wt:wt) VA for a period of 3 wk. The incorporation of VA and subsequent conversion to CLA in triglyceride was measured in adipose tissue. Glucose and insulin metabolism were assessed via a conscious adapted meal tolerance test procedure. Plasma lipids as well as serum inflammatorycytokineconcentrationsweremeasuredbycommerciallyavailableassays.VAsupplementationdidnotresult in any observable adverse health effects in either lean or obese JCR:LA-cp rats. After 3 wk of feeding, body weight, food intake,andglucose/insulinmetabolismdidnotdifferbetweenVA-supplementedandcontrolgroups.TheincorporationofVA andCLAintoadiposetriglyceridesinobeseratsfedVAincreasedby1.5-foldand6.5-fold,respectively,comparedwithobese ratsfedthecontroldiet.Themoststrikingeffectwasa40%decrease(P ,0.05)infastingtriglycerideconcentrationsinVAtreated obese rats relative to obese controls. Serum Il-10 concentration was decreasedby VA, regardlessof genotype (P , 0.05). In conclusion, short-term dietary supplementation of 1.5% VA did not result in any detrimental metabolic effects in JCR:LA-cprats.Incontrast,dietaryVAhadsubstantialhypo-triglyceridemiceffects,suggestinganewbioactivityofthisfatty