Conjugated Linoleic Acid Impairs Endothelial Function

Abstract

Objectives-To determine the effect of dietary supplementation with conjugated linoleic acid (CLA) on body mass index (BMI), body fat distribution, endothelial function, and markers of cardiovascular risk. Methods and Results-Forty healthy volunteers with BMI Ͼ27 kg/m 2 were randomized to receive a CLA isomeric mixture or olive oil in a 12-week double-blind study. Subcutaneous body fat and abdominal/hepatic fat content were assessed using skin-fold thicknesses and computed tomography scanning, respectively. Endothelial function was assessed by brachial artery flow-mediated dilatation (FMD). Plasma isoprostanes were measured as an index of oxidative stress. CLA supplementation did not result in a significant change in BMI index or total body fat. There was a significant decrease in limb (Ϫ7.8 mm, PϽ0.001), but not torso skin-fold thicknesses or abdominal or liver fat content. Brachial artery FMD declined (Ϫ1.3%, Pϭ0.013), and plasma F2-isoprostanes increased (ϩ91pg/mL, Pϭ0.042). Conclusions-A CLA isomeric mixture had at most modest effects on adiposity and worsened endothelial function. On the basis of these results, the use of the isomeric mixture of CLA as an aid to weight loss cannot be recommended.

A Systematic Review of the Efficacy of Bioactive Compounds in Cardiovascular Disease: Carbohydrates, Active Lipids and Nitrogen Compounds

“…Only one of those studies was conducted among healthy subjects, with being male as the inclusion criterion (19-35 years) [20]. The subjects recruited in the other two studies were BMI >25 kg/m 2 , one of them with LDL phenotype B as requirement for participating, both between 35 and 65 years [21,22]. One article assessed CLA's effect in active rheumatoid arthritis patients [23].…”

“…Moreover, there were no significant changes in plasma lipids profile. In addition, Taylor et al [21] observed an impairment of endothelial function and increase in markers of oxidative stress, since plasma 8-iso-PGF2α increased after 4.5 g/day of CLA administration. In addition, Raff et al [20] observed higher urinary excretion of 8-iso-PGF2α, increasing lipids peroxidation.…”

“…Even so, there are not enough preceding publications and grade of evidence for making a recommendation in these patients. Furthermore, Taylor et al [21], reported that CLA administration in men with BMI >27 kg/m 2 degraded endothelial function, apart from increasing plasma 8-iso-PGF2α. Additionally, Raff et al [20] found an increase in urinary excretion of 8-iso-PGF2α, resulting in lipid peroxidation increased a relevant risk factor for atherosclerosis.…”

Os efeitos do ácido linoléico conjugado no metabolismo animal: avanço das pesquisas e perspectivas para o futuro

“…Com exceção do trabalho de Belury et al 94 , que observaram redução da glicose plasmática em indivíduos portadores de diabetes tipo 2, a maioria dos estudos revisados demonstrou aumento de glicose plasmática, tendência para aumento da insulina plasmática e redução da sensibilidade à insulina 8,65,79,90,95 . Apenas os trabalhos recentes de Tricón et al 80 e de Taylor et al 96 reúnem dados que os permitem concluir que ambos os isômeros de CLA não apresentaram efeitos adversos sobre as concentrações plasmáticas de glicose e insulina e sobre a sensibilidade à ação da insulina.…”

“…A partir de então muitos foram os estudos com diversos animais [102][103][104] , com culturas de adipócito de roedores e humanos [105][106][107][108][109] e com humanos 8,65,[74][75][76][77][78][79][80]90,95,96,[110][111][112][113][114][115][116] , que surgiram com o objetivo de avaliar a propriedade de redução da gordura corporal, bem como elucidar os mecanismos de ação pelos quais o CLA desempenha esse papel.…”