Effect of CLA supplementation on immune function in young healthy volunteers

Eur J Clin Nutr. 2005 Apr;59(4):508-17. doi: 10.1038/sj.ejcn.1602102.


Objectives: This study investigated the effect of dietary CLA supplementation (3g/day; 50:50 mix of the two major isomers) on the immune system and plasma lipids and glucose of healthy human (male and female) volunteers.

Design: Double-blind, randomized, reference-controlled study. SUBJECT AND INTERVENTION: A total of 28 healthy male and female participants aged 25-50 y received either high oleic sunflower oil (reference) or 50% CLA 9-11 and 50% CLA 10-12 CLA isomers (50:50 CLA-triglyceride form). The treatments were given as supplements in soft-gel capsules providing a total 3 g (6 x 500 mg capsules) per day in treatment groups for 12 weeks. A 12-week washout period followed the intervention period.

Results: Levels of plasma IgA and IgM were increased (P < 0.05 and 0.01 respectively), while plasma IgE levels were decreased (P < 0.05). CLA supplementation also decreased the levels of the proinflammatory cytokines, TNF-alpha and IL-1beta (P < 0.05), but increased the levels of the anti-inflammatory cytokine, IL-10 (P < 0.05). Another aspect of immune function, delayed type hypersensitivity (DTH) response, was decreased during and after CLA supplementation (P < 0.05). However, plasma glucose, lipids, lymphocyte phenotypic results were not affected significantly by CLA.

Conclusion: This is the first study to show that CLA, a fatty acid naturally found in dairy and meat products, can beneficially affect immune function in healthy human volunteers.

Sponsorship: This study was supported by Loders-Croklaan, The Netherlands and SEERAD (Scottish Executive Environmental Rural and Agriculture Department).

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / drug effects
  • C-Reactive Protein / drug effects
  • Cytokines / biosynthesis
  • Dietary Supplements*
  • Double-Blind Method
  • Female
  • Humans
  • Hypersensitivity, Delayed
  • Immunity / drug effects*
  • Immunity / physiology
  • Immunoglobulins / blood
  • Immunoglobulins / drug effects
  • Linoleic Acids, Conjugated / pharmacology*
  • Lipids / blood
  • Lymphocytes / drug effects
  • Male
  • Reference Values
  • Sex Factors
  • Time Factors


  • Blood Glucose
  • Cytokines
  • Immunoglobulins
  • Linoleic Acids, Conjugated
  • Lipids
  • C-Reactive Protein