1. ¹Unilever Health Institute, Unilever Research Vlaardingen, Vlaardingen, The Netherlands
2. ²TNO Nutrition and Food Research, Zeist, The Netherlands
3. ³Loders Croklaan, Lipid Nutrition, Wormerveer, The Netherlands

Correspondence: Dr R Albers, Unilever Health Institute, PO Box 114, 3130 AC Vlaardingen, The Netherlands. E-mail: ruud.albers@unilever.com

Guarantor: R Albers.

Contributors: VD-T was responsible for the production and characterization of the CLA used in the study. RA, RvdW, EB and HH were involved in the planning of the study. EB and HH coordinated the performance of the study at TNO and together with RA and RvdW completed the analyses of the study. All contributors took part in the writing process and final compilation of the manuscript.

Received 27 March 2002; Revised 10 June 2002; Accepted 26 June 2002.

Abstract

Objectives: To study the effects of two different mixtures of the main conjugated linoleic acid (CLA) isomers cis-9, trans-11 CLA and trans-10, cis-12 CLA on human immune function.

Design: Double-blind, randomized, parallel, reference-controlled intervention study.

Subjects and intervention: Seventy-one healthy males aged 31–69 y received one of the following treatments: (1) mixture of 50% c9,t11 CLA and 50% t10,c12 CLA isomers (CLA 50:50); (2) mixture of 80% c9,t11 CLA and 20% t10,c12 CLA isomers (CLA 80:20); and (3) sunflower oil fatty acids (reference). The treatments were given as supplements in softgel capsules providing a total of 1.7 g (c9,t11+t10,c12) CLA fatty acids (50:50) or 1.6 g (c9,t11+t10,c12) CLA glycerides (80:20) per day in treatment groups for 12 weeks.

Results: Almost twice as many subjects reached protective antibody levels to hepatitis B when consuming CLA50:50 fatty acids (15/24, 62%) compared with subjects consuming the reference substance (7/21, 33%, P=0.075). In subjects consuming CLA 80:20 glycerides this was 8/22 (36%). Other aspects of immune function, ie DTH responses, NK cell activity, lymphocyte proliferation and production of TNF-, IL1-, IL6, IFN-, IL2, IL4, and PGE₂, were not affected.

Conclusion: This is the first study that suggests that CLA may beneficially affect the initiation of a specific response to a hepatitis B vaccination. This was seen in the CLA 50:50, but not in the CLA 80:20 group.

Sponsorship: This study was supported by Loders Croklaan.