The effects of conjugated linoleic acid supplementation on immune function in healthy volunteers.
OBJECTIVE
To assess the effects of dietary supplementation using two isomeric blends of conjugated linoleic acid (CLA) on immune function in healthy human volunteers.


METHODS
Double-blind, randomised, placebo-controlled intervention trial.


METHODS
A total of 55 healthy volunteers (n=20 males, n=35 females) were randomised into one of three study groups who received 3 g/day of a fatty acid blend containing a 50:50 cis-9, trans-11: trans-10, cis-12 CLA isomer blend (2 g CLA), and 80:20 cis-9, trans-11: trans-10, cis-12 (80:20) CLA isomer blend (1.76 g CLA) or linoleic acid (control, 2 g linoleic acid) for 8 weeks.


RESULTS
Supplementation with the 80:20 CLA isomer blend significantly (P< or =0.05) enhanced PHA-induced lymphocyte proliferation. CLA decreased basal interleukin (IL)-2 secretion (P< or =0.01) and increased PHA-induced IL-2 and tumor necrosis factor alpha (TNF(alpha)) production (P< or =0.01). However, these effects were not solely attributable to CLA as similar results were observed with linoleic acid. CLA supplementation had no significant effect on peripheral blood mononuclear cells IL-4 production, or on serum-soluble intercellular adhesion molecule-1 (sICAM-1) or plasma prostaglandin E2 (PGE2) or leukotreine B4 (LTB4) concentrations.


CONCLUSIONS
This study shows that CLA supplementation had a minimal effect on the markers of human immune function. Furthermore, supplementation with CLA had no immunological benefit compared with linoleic acid.
Nugent
A P
AP
Molecular Nutrition, Department of Clinical Medicine, Trinity Centre for Health Sciences, St James's Hospital, Dublin, Ireland.
Roche
H M
HM
Noone
E J
EJ
Long
A
A
Kelleher
D K
DK
Gibney
M J
MJ
D000328:Adult; D016207:Cytokines / Q000096:biosynthesis*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects* / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis; D007536:Isomerism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D019787:Linoleic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D044243:Linoleic Acids, Conjugated / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D016207:Cytokines; D007376:Interleukin-2; D044243:Linoleic Acids, Conjugated; D014409:Tumor Necrosis Factor-alpha; D019787:Linoleic Acid