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 1 y does not prevent weight or body fat regain.
BACKGROUND Conjugated linoleic acid ( CLA ) is marketed as a safe , simple , and effective dietary supplement to promote the loss of body fat and weight . However , most previous studies have been of short duration and inconclusive , and some recent studies have question ed the safety of long-term supplementation with CLA . OBJECTIVE Our aim was to assess the effect of 1-y supplementation with CLA ( 3.4 g/d ) on body weight and body fat regain in moderately obese people . DESIGN One hundred twenty-two obese healthy subjects with a body mass index ( in kg/m2 ) > 28 underwent an 8-wk dietary run-in with energy restriction ( 3300 - 4200 kJ/d ) . One hundred one subjects who lost > 8 % of their initial body weight were subsequently r and omly assigned to a 1-y double-blind CLA ( 3.4 g/d ; n = 51 ) or placebo ( olive oil ; n = 50 ) supplementation regime in combination with a modest hypocaloric diet of -1250 kJ/d . The effects of treatment on body composition and safety were assessed with the use of dual-energy X-ray absorptiometry and with blood sample s and the incidence of adverse events , respectively . RESULTS After 1 y , no significant difference in body weight or body fat regain was observed between the treatments . The CLA group ( n = 40 ) regained a mean ( + /-SD ) 4.0 + /- 5.6 kg body weight and 2.1 + /- 5.0 kg fat mass compared with a regain of 4.0 + /- 5.0 kg body weight and 2.7 + /- 4.9 kg fat mass in the placebo group ( n = 43 ) . No significant differences in reported adverse effects or indexes of insulin resistance were observed , but a significant increase in the number of leukocytes was observed with CLA supplementation . CONCLUSION A 3.4-g daily CLA supplementation for 1 y does not prevent weight or fat mass regain in a healthy obese population
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 .