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 .
Effects of dietary supplementation with conjugated linoleic acid on experimental human rhinovirus infection and illness.
BACKGROUND Because studies suggest that the dietary supplement conjugated linoleic acid ( CLA ) has immunomodulatory activities that might benefit common colds , we performed two studies of CLA effects in experimental human rhinovirus ( HRV ) infection . METHODS The first study explored whether CLA supplementation ( Safflorin ; Loders Croklaan , BV , Wormerveer , the Netherl and s ) altered the virological or clinical course of experimental HRV infection , and the second explored whether CLA affected the frequency and severity of HRV cold-associated sore throat and cough . The trials were r and omized , double-blinded and placebo-controlled . In total , 50 healthy volunteers aged 18 - 45 years and susceptible to HRV type-39 ( serum neutralizing antibody titre < or = 1:2 ) participated in study 1 and 80 similar volunteers susceptible to Hank 's HRV participated in study 2 . Participants ingested CLA 2 g/day or placebo for 4 weeks before and 4 days following intranasal HRV inoculation . The primary endpoint for study 1 was the frequency of colds and for study 2 was the symptom severity scores for sore throat and cough . RESULTS In study 1 , 10/24 ( 42 % ) placebo compared with 7/21 ( 33 % ) CLA participants developed colds ( P = 0.53 ) . CLA was associated with significant reductions in mean scores for cough ( 0 CLA versus 0.9 placebo ) and sore throat ( 0.8 CLA versus 2.9 placebo ) . In study 2 , clinical colds developed in 19/33 ( 58 % ) placebo and 27/43 ( 63 % ) CLA participants . Symptom scores for cough ( 0.9 CLA versus 1.0 placebo ) and sore throat ( 2.6 CLA versus 3.2 placebo ) were not significantly different . Similarly no differences in nasal viral titres or serological responses were found . CONCLUSIONS CLA dietary supplementation had no consistent effects on the virological or clinical course of experimental HRV colds . A larger study would be required to detect more subtle effects of CLA on HRV cold-associated symptoms
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 .