Conjugated linoleic acid: a functional nutrient in the different pathophysiological components of the metabolic syndrome?
OBJECTIVE
Much attention has focused on the therapeutic potential of conjugated linoleic acid with the most abundant isomers being cis-9,trans-11 conjugated linoleic acid and trans-10,cis-12 conjugated linoleic acid. Initial animal studies associated conjugated linoleic acid with beneficial health properties, such as reducing the risk of cancer, diabetes, atherosclerosis, inflammation and obesity. This review has appraised the evidence in relation to the effect of conjugated linoleic acid on components of the metabolic syndrome (clinically or experimentally), in particular, obesity, insulin resistance, atherosclerosis and inflammation.


RESULTS
More recent human conjugated linoleic acid supplementation studies have often shown conflicting and less convincing health benefits. The marked variation between studies may reflect the isomer-specific effect of the individual conjugated linoleic acid isomers, which can often have opposing effects. Detrimental effects have been observed in some studies, in particular after supplementation with the trans-10,cis-12 conjugated linoleic acid isomer.


CONCLUSIONS
Further studies and long-term clinical trials will be required to determine the efficacy and safety of conjugated linoleic acid isomers before conjugated linoleic acid could be considered as a functional nutrient in humans.
Toomey
Sinead
S
Nutrigenomics Research Group, Department of Clinical Medicine, Institute of Molecular Medicine, Trinity Health Sciences Centre, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland.
McMonagle
Jolene
J
Roche
Helen M
HM
D050197:Atherosclerosis / Q000517:prevention & control; D003257:Consumer Product Safety; D019317:Evidence-Based Medicine; D006801:Humans; D007249:Inflammation / Q000517:prevention & control; D007328:Insulin / Q000378:metabolism*; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000737:chemistry / Q000627:therapeutic use*; D050356:Lipid Metabolism / Q000187:drug effects*; D024821:Metabolic Syndrome / Q000178:diet therapy / Q000378:metabolism*; D009765:Obesity
D007328:Insulin; D044243:Linoleic Acids, Conjugated