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 .
Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men.
The usefulness of conjugated linoleic acid ( CLA ) as a nutraceutical remains ambiguous . Our objective was , therefore , to investigate the effect of CLA on body composition , blood lipids , and safety biomarkers in overweight , hyperlipidemic men . A double-blinded , 3-phase crossover trial was conducted in overweight ( BMI ≥ 25 kg/m(2 ) ) , borderline hypercholesterolemic [ LDL-cholesterol ( C ) ≥ 2.5 mmol/L ] men aged 18 - 60 y. During three 8-wk phases , each separated by a 4-wk washout period , 27 participants consumed under supervision in r and om order 3.5 g/d of safflower oil ( control ) , a 50:50 mixture of trans 10 , cis 12 and cis 9 , trans 11 ( c9 , t11 ) CLA : Clarinol G-80 , and c9 , t11 isomer : c9 , t11 CLA . At baseline and endpoint of each phase , body weight , body fat mass , and lean body mass were measured by DXA . Blood lipid profiles and safety biomarkers , including insulin sensitivity , blood concentrations of adiponectin , and inflammatory ( high sensitive-C-reactive protein , TNFα , and IL-6 ) and oxidative ( oxidized-LDL ) molecules , were measured . The effect of CLA consumption on fatty acid oxidation was also assessed . Compared with the control treatment , the CLA treatments did not affect changes in body weight , body composition , or blood lipids . In addition , CLA did not affect the β-oxidation rate of fatty acids or induce significant alterations in the safety markers tested . In conclusion , although no detrimental effects were caused by supplementation , these results do not confirm a role for CLA in either body weight or blood lipid regulation in humans
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 .