Effect of conjugated linoleic acids, vitamin E and their combination on the clinical outcome of Iranian adults with active rheumatoid arthritis

Int J Rheum Dis. 2009 Apr;12(1):20-8. doi: 10.1111/j.1756-185X.2009.01374.x.


Background: Despite beneficial effects of conjugated linoleic acids (CLAs) in animal studies, there is little information on their effects on human inflammatory and autoimmune diseases.

Aim: To investigate the effects of CLAs as an adjuvant therapy on the clinical manifestations of rheumatoid arthritis (RA) in adults with an active disease.

Methods: In a randomized, double-blind placebo-controlled trial, 87 patients with active RA were divided into four groups receiving one of the following daily supplements for 3 months: group C: CLAs 2.5 g equivalent to 2 g mixture of cis 9-trans 11 and trans 10-cis12 CLAs at a rate of 50/50; group E: vitamin E: 400 mg; group CE: CLAs and vitamin E at above doses; group P: placebo. Serum alpha-tocopherol was determined by high-performance liquid chromatography. Clinical data was determined by physician examination and filling the questionnaire by interview. Complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-Reactive protein (CRP) and rheumatoid factor (RF) were measured in each patient. DAS28 (diseases activity score) was also determined.

Results: A 3-month supplementation resulted significant reduction in DAS28, pain and morning stiffness in the groups C and CE compared with group P (P < 0.05). Compared with the baseline, ESR levels decreased significantly in the groups C (P < or = 0.05), E (P < or = 0.05) and CE (P < or = 0.001). Group CE had significantly lower ESR levels than group P (P v 0.05). CRP dropped non-significantly in all four groups (P > 0.1). The reduction of white blood cell count was significant in group CE compared with other groups (P < 0.05). Decrease in platelet count was non-significant in groups CE, C, and E. Changes in RF, body mass index, red blood cell count and hemoglobin were not significant in four groups, while RF decreased non-significantly in groups CE and E. In comparison with the baseline, alpha-tocopherol increased significantly in groups C (P < or = 0.05), E (P < or = 0.01) and CE (P < or = 0.001) and in groups E and CE compared with group P.

Conclusion: CLA supplementation resulted in significant improvement in clinical manifestation among RA patients and may be useful in their treatments.

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Antioxidants / therapeutic use*
  • Antirheumatic Agents / therapeutic use*
  • Arthritis, Rheumatoid / drug therapy*
  • Arthritis, Rheumatoid / physiopathology
  • Blood Sedimentation / drug effects
  • Dietary Supplements
  • Double-Blind Method
  • Female
  • Humans
  • Linoleic Acids, Conjugated / therapeutic use*
  • Male
  • Middle Aged
  • Severity of Illness Index
  • Treatment Outcome
  • Vitamin E / blood
  • Vitamin E / therapeutic use*
  • Young Adult
  • alpha-Tocopherol / blood


  • Antioxidants
  • Antirheumatic Agents
  • Linoleic Acids, Conjugated
  • Vitamin E
  • alpha-Tocopherol