Raff Marianne, Tholstrup Tine, Toubro Søren, Bruun Jens M, Lund Pia, Straarup Ellen M, Christensen Robin, Sandberg Maria B, Mandrup Susanne
Department of Human Nutrition, Faculty of Life, University of Copenhagen, Frederiksberg 1958, Denmark.
J Nutr. 2009 Jul;139(7):1347-52. doi: 10.3945/jn.109.104471. Epub 2009 Jun 3.
Isomers of conjugated linoleic acids (CLA) reduce fat mass (FM) and increase insulin sensitivity in some, but not all, murine studies. In humans, this effect is still debatable. In this study, we compared the effect of 2 CLA supplements on total and regional FM assessed by dual energy X-ray absorptiometry, changes in serum insulin and glucose concentrations, and adipose tissue (AT) gene expression in humans. In a double-blind, parallel, 16-wk intervention, we randomized 81 healthy postmenopausal women to 1) 5.5 g/d of 40/40% of cis9,trans11-CLA (c9,t11-CLA) and trans10,cis12-CLA (t10,c12-CLA) (CLA-mix); 2) cis9, trans11-CLA (c9,t11-CLA); or 3) control (olive oil). We assessed all variables before and after the intervention. The CLA-mix group had less total FM (4%) and lower-body FM (7%) than the control (P = 0.02 and < 0.001, respectively). Post hoc analyses showed that serum insulin concentrations were greater in the CLA-mix group (34%) than the control group (P = 0.02) in the highest waist circumference tertile only. AT mRNA expression of glucose transporter 4, leptin, and lipoprotein lipase was lower, whereas expression of tumor necrosis factor-alpha was higher in the CLA-mix group than in the control group (P < 0.04). In conclusion, a 50:50 mixture of c9,t11- and t10,c12-CLA isomers resulted in less total and lower-body FM in postmenopausal women and greater serum insulin concentrations in the highest waist circumference tertile. Future research is needed to confirm the insulin desensitizing effect of the CLA mixture and the effect on the mRNA expression of adipocyte-specific genes in humans.
共轭亚油酸（CLA）的异构体在一些（但并非所有）小鼠研究中可减少脂肪量（FM）并提高胰岛素敏感性。在人类中，这种效果仍存在争议。在本研究中，我们比较了两种CLA补充剂对通过双能X线吸收法评估的全身和局部FM、血清胰岛素和葡萄糖浓度变化以及人体脂肪组织（AT）基因表达的影响。在一项为期16周的双盲、平行干预研究中，我们将81名健康的绝经后女性随机分为三组：1）每天服用5.5克含有40/40%顺式9，反式11 - CLA（c9，t11 - CLA）和反式10，顺式12 - CLA（t10，c12 - CLA）的混合物（CLA - 混合组）；2）顺式9，反式11 - CLA（c9，t11 - CLA）组；3）对照组（橄榄油）。我们在干预前后评估了所有变量。CLA - 混合组的全身FM（减少4%）和下半身FM（减少7%）均低于对照组（P值分别为0.02和<0.001）。事后分析表明，仅在腰围最高三分位数组中，CLA - 混合组的血清胰岛素浓度比对照组高34%（P = 0.02）。CLA - 混合组中葡萄糖转运蛋白4、瘦素和脂蛋白脂肪酶的AT mRNA表达较低，而肿瘤坏死因子 - α的表达高于对照组（P < 0.04）。总之，c9，t11 - 和t10，c12 - CLA异构体的50:50混合物可使绝经后女性的全身和下半身FM减少，且在腰围最高三分位数组中血清胰岛素浓度更高。需要进一步的研究来证实CLA混合物对胰岛素的脱敏作用以及对人体脂肪细胞特异性基因mRNA表达的影响。
