肉碱(补剂测评：共轭亚油酸（CLA）)-前沿资讯

说到减脂补剂，人们首先会想到左旋肉碱（L-carnitine），接着就是共轭亚油酸（CLA）。我已经写过关于左旋肉碱的文章了，所以今天我们来测评一下共轭亚油酸。

CLA是Conjugated Linoleic Acid的缩写，中文是共轭亚油酸，一种omega 6脂肪酸。CLA主要存在于肉类、奶制品和黄油。

CLA被销售为一种帮助减脂的产品，据说能增加消耗量、加快脂肪分解和燃烧，抑制脂肪堆积。这些效果都和一种叫做PPAR的蛋白质有关。

(资料图片仅供参考)

PPAR（Peroxisome Proliferator Activated Receptor）或过氧化物酶体增殖物激活受体是一群管理细胞分化、细胞生长和新陈代谢的蛋白质。PPAR又分为-alpha、-beta和-gamma，但我们只会讲到和。PPAR是一种促进脂肪消化和使用的蛋白质，在能量不足的情况下激活。PPAR能刺激脂肪吸收和脂肪形成。

研究发现3-8，CLA似乎能激活PPAR，并抑制PPAR，从而达到减脂的效果。不过，这些研究只是一些试管和老鼠实验，或一些短期的体内研究（例如在吃入CLA之后的几小时里，体内会发生什么变化，但并没有作出长期的跟踪）。所以想要知道这种补剂真的是否有效，我们得依据更实际的长期研究结果而得知。

最初的CLA研究是从90年底开始的，至今积累了大概150 项研究1。当然，像上面所说的，我们只看那些长期的研究。

大概有23项研究查看了在补充CLA之后，对身体组合的变化。其中有11项研究发现CLA的确能帮助减脂9-19。

例如在这项研究里9：

Pinkoski等人招来了85位测试者，43位女士，42位男士，18-45岁，至少有2年的抗阻力训练经验。将他们分成了两组，CLA组（5克）和安慰剂组，并让他们进行了7周的周期化全身抗阻力训练。饮食方面没有作出任何改变。7周之后结果发现，CLA组的平均脂肪重量降低了0.8kg，安慰剂组却上升了0.4kg。

你可能会想：“CLA有减脂效果啊，而且比安慰剂更好。”。的确，但这些研究所得出的减脂效果都非常差。以上所有研究结果结合起来，平均所降低的体重在1kg左右。最短的试验时间是6周，最长的是1年。这也说明了CLA的效果很个人化，因为1kg是平均结果，也就是说，某些人的体重并没有变化，某些人的体重增重了，某些人的体重降低了。此外，另12项研究发现CLA的补充和安慰剂或控制组相比并没有更好的效果20-31，所以CLA的研究结果十分不可靠。

例如在这项研究里27：

Ribeiro等人招募了34位肥胖女性，分成了两组，CLA组（3.2克）和安慰剂组，并让她们进行了8周的有氧训练。8周之后结果发现，两组之间没有明显的区别，CLA组的体脂率降低了0.8%，安慰剂组降低了0.6%。

所以，至今CLA的研究结果不够明显，也不够可靠，需要更多效果更明显的研究。

不值得。

想减脂没有捷径，也没有神奇的减肥方法，你得确保自己每天所消耗的热量大于所摄入的热量，也就是热量差。无论你吃多少减脂补剂，身体不处于一个热量差状态就无法减脂，很简单。

1. https://examine.com/supplements/conjugated-linoleic-acid/

2. https://en.wikipedia.org/wiki/Peroxisome_proliferator-activated_receptor

3. Moya-camarena et al 1999. Conjugated linoleic acid is a potent naturally occurring ligand and activator of PPARalpha.

4. Moya-camarena et al 1999. Conjugated linoleic acid activates peroxisome proliferator-activated receptor alpha and beta subtypes but does not induce hepatic peroxisome proliferation in Sprague-Dawley rats.

5. Brown et al 2003. Isomer-specific regulation of metabolism and PPARgamma signaling by CLA in human preadipocytes.

6. Nazare et al 2007. Daily intake of conjugated linoleic acid-enriched yoghurts: effects on energy metabolism and adipose tissue gene expression in healthy subjects.

7. Hermann et al 2009. Isomer-specific effects of CLA on gene expression in human adipose tissue depending on PPARgamma2 P12A polymorphism: a double blind, randomized, controlled cross-over study.

8. Brown et al 2001. Trans-10, cis-12, but not cis-9, trans-11, conjugated linoleic acid attenuates lipogenesis in primary cultures of stromal vascular cells from human adipose tissue.

9. Pinkoski et al 2006. The effects of conjugated linoleic acid supplementation during resistance training.

10. Watras et al 2007. The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain.

11. Racine et al 2010. Effect of conjugated linoleic acid on body fat accretion in overweight or obese children.

12. Gaullier et al 2005. Supplementation with conjugated linoleic acid for 24 months is well tolerated by and reduces body fat mass in healthy, overweight humans.

13. Gaullier et al 2004. Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans.

14. Colakoglu et al 2006. Cumulative effects of conjugated linoleic acid and exercise on endurance development, body composition, serum leptin and insulin levels.

15. Sneddon et al 2008. Effect of a conjugated linoleic acid and omega-3 fatty acid mixture on body composition and adiponectin.

16. Blankson et al 2000. Conjugated linoleic acid reduces body fat mass in overweight and obese humans.

17. Chen et al 2012. Effect of conjugated linoleic acid supplementation on weight loss and body fat composition in a Chinese population.

18. Norris et al 2009. Comparison of dietary conjugated linoleic acid with safflower oil on body composition in obese postmenopausal women with type 2 diabetes mellitus.

19. Laso et al 2007. Effects of milk supplementation with conjugated linoleic acid (isomers cis-9, trans-11 and trans-10, cis-12) on body composition and metabolic syndrome components.

20. Joseph et al 2011. Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men.

21. Nazare et al 2007. Daily intake of conjugated linoleic acid-enriched yoghurts: effects on energy metabolism and adipose tissue gene expression in healthy subjects.

22. Larsen et al 2006. Conjugated linoleic acid supplementation for 1 y does not prevent weight or body fat regain.

23. Lambert et al 2007. Conjugated linoleic acid versus high-oleic acid sunflower oil: effects on energy metabolism, glucose tolerance, blood lipids, appetite and body composition in regularly exercising individuals.

24. Syvertsen et al 2007. The effect of 6 months supplementation with conjugated linoleic acid on insulin resistance in overweight and obese.

25. Venkatramanan et al 2010. Milk enriched with conjugated linoleic acid fails to alter blood lipids or body composition in moderately overweight, borderline hyperlipidemic individuals.

26. Diaz et al 2008. Chromium picolinate and conjugated linoleic acid do not synergistically influence diet- and exercise-induced changes in body composition and health indexes in overweight women.

27. Ribeiro et al 2016. Effect of Conjugated Linoleic Acid Associated With Aerobic Exercise on Body Fat and Lipid Profile in Obese Women: A Randomized, Double-Blinded, and Placebo-Controlled Trial.

28. Wanders et al 2010. Effect of a high intake of conjugated linoleic acid on lipoprotein levels in healthy human subjects.

29. Raff et al 2008. A diet rich in conjugated linoleic acid and butter increases lipid peroxidation but does not affect atherosclerotic, inflammatory, or diabetic risk markers in healthy young men.

30. Steck et al 2007. Conjugated linoleic acid supplementation for twelve weeks increases lean body mass in obese humans.

31. Malpuech-Brugère et al 2004. Effects of two conjugated linoleic Acid isomers on body fat mass in overweight humans.

关键词： 研究结果 左旋肉碱 的情况下