There was a significant heterogeneity for the impact of CLA  on CRP and IL-6 , but not TNF-α .
Conclusions This meta- analysis showed that CLA supplementation may increase inflammatory markers ( CRP and TNF-α ) .
Background / objectives Conjugated linoleic acid ( CLA ) is a polyunsaturated fatty acid with attractive biological activities .
Numerous studies have been conducted on the inflammation-lowering effects of CLA in in vitro and animal models .
However , the effects of CLA treatment on the inflammatory markers in humans are controversial .
Fish oil in combination with high or low intakes of linoleic acid lowers plasma triacylglycerols but does not affect other cardiovascular risk markers in healthy men.
Both ( n-3 ) long-chain PUFA ( LCPUFA ) and linoleic acid [ LA , 18:2(n-6 ) ] improve cardiovascular disease ( CVD ) risk factors , but a high-LA intake may weaken the effect of ( n-3 ) LCPUFA . In a controlled , double-blind , 2 x 2-factorial 8-wk intervention , we investigated whether fish oil combined with a high- or low-LA intake affects overall CVD risk profile .  Healthy men ( n = 64 ) were r and omized to 5 mL/d fish oil capsules ( FO ) [ mean intake 3.1 g/d ( n-3 ) LCPUFA ] or olive oil capsules ( control ) and to oils and spreads with either a high ( S/B ) or a low ( R/K ) LA content , result ing in a 7.3 g/d higher LA intake in the S/B groups than in the R/K groups . Diet , ( n-3 ) LCPUFA in peripheral blood mononuclear cells , blood pressure ( BP ) , heart rate ( HR ) , and plasma CVD risk markers were measured before and after the intervention . FO lowered fasting plasma triacylglycerol ( TAG ) ( P < 0.001 ) by 51 % and 19 % in the FO+R/K-group and FO+S/B-group , respectively , which was also reflected in postpr and ial TAG measured after the intervention ( P < 0.01 ) . Although a fat x FO interaction was found for monocyte chemoattractant protein-1 , neither the FO nor fat intervention affected fasting plasma cholesterol , glucose , insulin , fibrinogen , C-reactive protein , interleukin-6 , vascular cell adhesion molecule-1 , P-selectin , oxidized LDL , cluster of differentiation antigen 40 lig and ( CD40L ) , adiponectin , or fasting or postpr and ial BP or HR after adjustment for body weight changes . In conclusion , neither fish oil supplementation nor the LA intake had immediate pronounced effects on the overall CVD risk profile  in healthy men , but fish oil lowered plasma TAG in healthy subjects with initially low concentrations
There was a significant heterogeneity for the impact of CLA  on CRP and IL-6 , but not TNF-α .
Conclusions This meta- analysis showed that CLA supplementation may increase inflammatory markers ( CRP and TNF-α ) .
Background / objectives Conjugated linoleic acid ( CLA ) is a polyunsaturated fatty acid with attractive biological activities .
Numerous studies have been conducted on the inflammation-lowering effects of CLA in in vitro and animal models .
However , the effects of CLA treatment on the inflammatory markers in humans are controversial .