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 .
Increased α-linolenic acid intake lowers C-reactive protein, but has no effect on markers of atherosclerosis
Objective : To investigate the effects of increased alpha-linolenic acid (ALA)-intake on intima – media thickness ( IMT ) , oxidized low-density lipoprotein ( LDL ) antibodies , soluble intercellular adhesion molecule-1 ( sICAM-1 ) , C-reactive protein ( CRP ) , and interleukins 6 and 10 . Design : R and omized double-blind placebo-controlled trial . Subjects : Moderately hypercholesterolaemic men and women ( 55±10 y ) with two other cardiovascular risk factors (n=103).Intervention : Participants were assigned to a margarine enriched with ALA ( fatty acid composition 46 % LA , 15 % ALA ) or linoleic acid ( LA ) ( 58 % LA , 0.3 % ALA ) for 2 y. Results : Dietary ALA intake was 2.3 en% among ALA users , and 0.4 en% among LA users . The 2-y progression rate of the mean carotid IMT  ( ALA and LA : + 0.05 mm ) and femoral IMT ( ALA:+0.05 mm ; LA:+0.04 mm ) was similar , when adjusted for confounding variables . After 1 and 2 y , ALA users had a lower CRP level than LA users ( net differences −0.53 and −0.56 mg/l , respectively , P<0.05 ) . No significant effects were observed in oxidized LDL antibodies , and levels of sICAM-1 , interleukins 6 and 10 . Conclusions : A six-fold increased ALA intake lowers CRP , when compared to a control diet high in LA . The present study found no effects on markers for atherosclerosis . Sponsorship : The Dutch ‘ Praeventiefonds ’
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 .