Original Communication
European Journal of Clinical Nutrition (2005) 59, 742–750. doi:10.1038/sj.ejcn.1602132 Published online 13 April 2005
The effects of conjugated linoleic acid supplementation on immune function in healthy volunteers
Guarantors: AP Nugent and HM Roche.
Contributors: APN analysed the data and wrote the paper. HMR, EJN, AL, DKK and MJG provided consultation on the interpretation of the results and commented on the paper.
A P Nugent1, H M Roche1, E J Noone1, A Long2, D K Kelleher3 and M J Gibney1
- 1Molecular Nutrition, Department of Clinical Medicine, Trinity Centre for Health Sciences, St James's Hospital, Dublin, Ireland
- 2Department of Biochemistry, Royal College of Surgeons of Ireland, Dublin, Ireland
- 3Dublin Molecular Medicine Centre & Department of Clinical Medicine, Trinity Centre for Health Sciences, St James's Hospital, Dublin, Ireland
Correspondence: HM Roche, Molecular Nutrition, Department of Clinical Medicine, Trinity Centre for Health Sciences, St James's Hospital, James's Street, Dublin 8, Ireland. E-mail: hmroche@tcd.ie
Received 9 June 2004; Revised 20 December 2004; Accepted 14 January 2005; Published online 13 April 2005.
Abstract
Objective:
To assess the effects of dietary supplementation using two isomeric blends of conjugated linoleic acid (CLA) on immune function in healthy human volunteers.
Design:
Double-blind, randomised, placebo-controlled intervention trial.
Subjects and intervention:
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
0.05) enhanced PHA-induced lymphocyte proliferation. CLA decreased basal interleukin (IL)-2 secretion (P0.01) and increased PHA-induced IL-2 and tumor necrosis factor 
(TNF) production (P0.01). 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.
Sponsorship:
CLA supplements were provided by Loders Croklaan.
Keywords:
conjugated linoleic acid (CLA), immune function, cytokine
