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

Authors


: Farhad Shahram MD, Professor of Rheumatology, Tehran University of Medical Sciences, Rheumatology Research Center, Shariati Hospital, Kargar Avenue, Tehran, Iran. Email: shahram@neda.net

Abstract

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 α-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 ≤ 0.05), E (P ≤ 0.05) and CE (P ≤ 0.001). Group CE had significantly lower ESR levels than group P (P ≤ 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, α-tocopherol increased significantly in groups C (P ≤ 0.05), E (P ≤ 0.01) and CE (P ≤ 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.

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune disease with predominant synovial proliferation and a potential for destruction of articular cartilage. It is the most common inflammatory arthritis affecting 0.5–1.0% of the normal population around the world.1,2 Although its exact aetiology still remains unknown, a great number of studies have suggested the possible role of reactive oxygen species (ROS) in its pathogenesis.2,3 ROS have been implicated as mediators of tissue damage in patients with RA.3 The synovial fluid of the inflamed joints in RA is swarmed with activated neutrophils which produce large amounts of ROS.4 It has been suggested that enzymatic and/or non-enzymatic antioxidant systems are impaired in RA.5 High amounts and/or inadequate removal of ROS expose these patients to oxidative stress, which may cause severe metabolic malfunctions and biological macromolecule damage.5

These destructive chain reactions initiated by ROS can be broken by antioxidants, which are able to convert ROS into harmless derivatives.6 These antioxidants are also essential for inhibition of inflammation related to neutrophil functions.3 Several naturally occurring free radical scavengers, including beta-carotene, ascorbate and vitamin E help to maintain normal homeostatic levels of these reactive species.7 Vitamin E is known to interact with nitric oxide and one of its products (peroxy-nitrite) by its quinone derivative as a major oxidation product.8,9 Earlier studies have indicated that vitamin E significantly increases these activities and mRNA levels of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase in the liver of autoimmunity-prone mice.10 Vitamin E uncouples joint inflammation and joint destruction in this model of RA, with a beneficial effect on joint destruction.11 Conjugated linoleic acids (CLAs) are a generic term denoting a group of naturally occurring isomers of linoleic acids. The biological activities of CLA have received considerable attention due to their anti-cancer,12,13 anti-atherogenic14,15 and anti-diabetic effects.16 The efficacy of a selected 50 : 50 mix of two CLA isomers (10-trans, 12-cis-CLA and 9-cis, 11-trans-CLA) in triglyceride form was reported useful in improving immunity17–19 and lowering oxidation rate20–24 in animal models and cell cultures. Despite increasing knowledge regarding CLAs’ beneficial effects, the exact mechanisms of CLA on RA are not clear.19 This may be mediated by several of the following mechanisms: modulating cytokines such as interleukin (IL)-1, IL-4, IL-6, IL-8 and tumor necrosis factor (TNF)-α, decreasing peroxisome-proliferator activated receptor-γ activation possibly linked either directly or indirectly through nuclear factor-κB (NF-κB) activation, decreasing eicosanoid production such as prostaglandin E2 (PGE2) by inhibiting cyclooxygenase-2 (COX-2), decreasing nitric oxide, and/or decreasing expression of adhesion molecules and proteinase genes.17–19,25–29 There has always been concern over the instability of the very long-chain fatty acids and their susceptibility to oxidation.30 Santos-Zago et al. have indicated that feeding CLAs adequately supplemented with vitamin E accelerates CLA antioxidant activities.31

Therefore, this placebo-controlled study was conducted in patients with RA receiving standard anti-rheumatic treatment to investigate any complementary anti-inflammatory effects of CLA, as well as the synergistic effects of vitamin E.31

MATERIALS AND METHODS

A randomized double-blind placebo-controlled trial was conducted in a 12-week period in patients with active RA. The inclusion criteria were ages between 19–69 years, having RA for at least 2 years and fulfilling 1987 American College of Rheumatology (ACR) criteria for RA.32 Data on dietary habits, dietary supplements, smoking habits and drug history were obtained by face-to-face interview. Body mass index (BMI) was determined. The exclusion criteria were: abnormal renal and/or hepatic function, smoking, and history of myocardial infarction, pregnancy, taking vitamin and/or mineral supplements, and taking drugs such as thyroid hormones, estrogens, progesterone, diuretics or β-blockers. A written informed consent was obtained from all participants. The research protocol was approved by the Ethics Committee of Tehran University of Medical Sciences. The patients were randomly assigned to one of four treatment groups receiving CLA (group C), or vitamin E (group E), both CLA and vitamin E (group CE) or placebo (group P). Randomization was done by using Random Permuted Blocks procedure.

Conjugated linoleic acid was prescribed 2.5 grams daily as two capsules, containing 2 g both cis-9, trans-11 CLA and trans-10, cis-12 triglyceride type CLA in equal proportion. The daily dose of vitamin E (α-tocopherol) was 400 mg. Corn oil was the placebo of vitamin E and high oleic sun flower (HOSF) was the placebo of CLA. The vitamin E was used as under tolerable upper intake levels (1000 mg).33 Dosage levels of CLA were lower than used in many other studies where their levels of CLA had no side effects.34 The amount of nutrient intake was estimated using a 24-h dietary recall questionnaire for 2 consecutive days before and after the study using the USA Food Processor (version III) software. The subjects were asked not to alter their usual diets and physical activity throughout the study. The patients were examined by the same rheumatologist in each visit. Pain was measured by visual assessment scales (VAS) using a 0–100 mm scale. The disease activity was graded to non-active or active (mild, moderate and severe) according to the physician global assessment (PG). This was determined regarding both physical exams (joint pain, morning stiffness, joint swelling and tenderness) as well as acute phase reactants such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count and haemoglobin. Disease Activity Score (DAS28) was also determined for each patient.35 The type of disease-modifying antirheumatic drugs (DMARDs) and the amount of steroids and non-steroidal anti-inflammatory drugs (NSAIDs) used were determined for each patient at the baseline (by changing their dose to their equation as prednisolone and sodium diclofenac, respectively).

We was tried not to change the dose of anti-inflammatory drugs (steroids or NSAIDs) during the study period, and the patient was excluded from the study if the dose was changed.

Compliance with the supplementation was assessed by counting the number of capsules that were used as well as measuring serum α-tocopherol. White blood cell (WBC) count and platelet counts, ESR in the first hour, CRP, rheumatoid factor (RF), serum creatinine and uric acid levels were determined before and after treatment. Serum α-tocopherol was measured by high-performance liquid chromatography.36 CRP and RF values were determined with immunoturbidimetric assay.

Statistical analysis

All values are expressed as mean ± standard deviation (SD). Differences between four groups were determined by one-way analysis of variance (anova) for continuous data and the χ2-test for group data. Post hoc comparisons were performed with Tukey test. The differences before and after treatment in each group were determined by paired-sample t-test for quantitative variables and by Wilcoxon paired test for qualitative data. A value of P < 0.05 was considered to be statistically significant. Adjustment for differences in baseline covariates and changes in variables during the study were performed by analysis of covariance using general linear models. All data analyses were done by using SPSS Software.

RESULTS

Of 102 subjects entered into the study, 87 completed the study. Fifteen patients were excluded from the study due to either incomplete consumption of prescribed drugs (6 patients: 1 in each of groups C and CE, 2 in each of groups E and P), or changing the dose of their anti-inflammatory drugs (8 patients: 2 in each four groups), or side effects (1 patient in group C) (Fig. 1).

Figure 1.

Flow chart of the outcome of the patients studied.

Table 1 lists demographic, anthropometric, and clinical data for the four study groups at the baseline. There were no significant differences between the four groups before treatment regarding sex, age, disease duration, BMI, serum or daily intake of vitamin E and prednisolone (P < 0.05). However, patients in group P had been receiving lower amounts of NSAIDs. The kind of DMARD (hydroxichloroquine, choloroquine and methoterexate) and their doses did not change significance between the four groups (P < 0.05) (Table 2). There were no significant differences between groups at the baseline in various disease variables (morning stiffness, DAS28, PGA, joint tenderness, joint pain, number of swollen joints) (Tables 1 and 3) as well as WBC and platelet count, serum hemoglobin, ESR, serum levels of CRP and RF (Table 4). There were no significant changes in BMI, physical activity or medication during the study period (Tables 2 and 5).

Table 1.  Demographic, Anthropometric, and clinical Data for the Four Study Groups at the baseline
VariablesGroup P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
  • (Mean ± SD).

  • There were no significant differences between groups by anova (for means) or Chi-square (for sex ratio).

  • Group P, placebo; group C, conjugated linleic acids (CLAs); group E, vitamin E; group CE, CLAs + vitamin E; DAS28, Disease Activity Score 28; BMI, body mass index

Male/female3/193/194/175/17
Age (years)*47.95 ± 11.1446.23 ± 13.0749.33 ± 11.8943.77 ± 12.75
Duration of RA (years)*8.88 ± 8.659.95 ± 8.417.24 ± 5.827.64 ± 6.19
Vitamin E intake (mg per day)*7.9 ± 2.448.75 ± 2.317.78 ± 3.508.80 ± 3.44
Morning pain (mm)51.14 ± 24.3938.98 ± 23.79d40.24 ± 29.8554.55 ± 34.50
Night pain (mm)51.82 ± 28.3538.75 ± 28.4149.77 ± 30.7654.77 ± 32.60d
After activity pain (mm)62.95 ± 36.2757.98 ± 34.6257.86 ± 28.4855.45 ± 33.59d
Morning stiffness (hour)1.27 ± 0.771.27 ± 0.881.09 ± 0.891.27 ± 0.94b
Number of swollen joints6.45 ± 8.897.86 ± 8.236.71 ± 9.676.73 ± 6.67
Number joints with tenderness2.86 ± 1.676.23 ± 6.723.76 ± 4.883.41 ± 4.89
DAS284.35 ± 0.954.63 ± 1.264.59 ± 1.114.52 ± 1.08
BMI (kg/m2)28.48.92 ± 3.9427.18 ± 4.6327.14 ± 0.4.7025.65 ± 3.97
Serum vitamin E (µg/mL)4.83 ± 3.784.72 ± 4.415.24 ± 2.876.64 ± 4.64
Table 2.  The amount of NSAIDs and glucocorticoid used in patients with active RA before and after 3 months supplementation (mean ± SD)
Variables Group P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
  1. Group P, placebo; group C, conjugated linleic acids (CLAs); group E, vitamin E; group CE, CLAs + vitamin E.

  2. There were no significant baseline differences between groups by anova for all above factors (P ≤ 0.05). There were significant differences between groups after supplementation for all above factors by ancova (P < 0.01). Significant differences between before and after: *P ≤ 0.05; **P ≤ 0.01. After supplementation: †groups CE and C has significantly lower levels than group P (P ≤ 0.001); ‡group E had significantly higher levels than group P (P ≤ 0.05).

NSAIDsBefore0.26 ± 0.530.48 ± 0.84*†0.46 ± 0.75*‡0.70 ± 0.87*†
After0.45 ± 0.910.00 ± 0.000.11 ± 0.310.23 ± 0.67
GlucocorticoidBefore1.97 ± 0.871.76 ± 0.78*1.68 ± 0.812.09 ± 0.72**
After1.76 ± 0.661.48 ± 0.452.33 ± 2.461.78 ± 0.64
Table 3.  Physician global assessment (PGA) in patients with active RA before and after 3 months supplementation
VariablesGroup P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
P-value
(chi-square)
  1. Group P, placebo; group C, conjugated linleic acids (CLAs); group E, vitamin E; group CE, CLAs + vitamin E; NS, not significant

PGA (percent)    P ≤ 0.001
 Before     
Non-active 
 Mild36.45033.336.4 
Moderate59.136.457.140.9 
 Severe 5.413.6 9.522.7 
 After     
Non active59.114.340.9 
 Mild54.531.838.145.5 
Moderate36.4 4.542.913.6 
 Severe 9.1 4.8 
 P-value (Wilcoxon test)NSP = 0.01P = 0.033P = 0.01 
Table 4.  Levels of some clinical tests in patients with active RA before and after 3 months supplementation (mean ± SD)
Variables Group P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
  1. Group P, placebo; group C, conjugated linleic acids (CLAs); group E, vitamin E; group CE, CLAs + vitamin E; RF, rheumatoid factor; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; RBC, red blood cell; WBC, white blood cell.

  2. There were no significant baseline differences between groups by anova for all above factors. There were borderline significant differences between groups after supplementation by ancovaζ = 0.06. Statistically significant differences between before and after: *P ≤ 0.05; **P ≤ 0.01; ***P = 0.055. After supplementation, group CE had significantly lower levels than group P (P ≤ 0.05).

RF (IU/mL)Before76.30 ± 88.6364.46 ± 74.2281.31 ± 94.6380 ± 74.36
After91.97 ± 85.7871.78 ± 84.8072.36 ± 73.3372.90 ± 13.18
CRP (IU/mL)Before6.44 ± 7.907.19 ± 10.139.06 ± 14.335.24 ± 6.44
After5.48 ± 5.605.46 ± 5.534.76 ± 5.21***3.17 ± 3.90
ESR (mm/h) ζBefore28.36 ± 21.5526.81 ± 15.50*40.43 ± 26.22*28.45 ± 17.26**
After27.04 ± 18.9519.14 ± 10.9432.28 ± 22.9617.77 ± 12.20
Hb (g/dL)Before12.78 ± 1.2513.09 ± 1.4512.58 ± 0.9813.13 ± 0.95
After12.99 ± 1.3213.12 ± 1.4512.50 ± 1.2013.17 ± 1.05
RBC (mL/µL)Before4.85 ± 0.784.82 ± 0.494.62 ± 0.0.404.74 ± 0.51
After4.89 ± 0.854.97 ± 0.784.55 ± 0.434.72 ± 0.58
WBC (/µL)Before8587.7 ± 2269.97728.5 ± 2465.47724.76 ± 1834.79280.9 ± 2296.3*
After7752.9 ± 2143.78090 ± 1632.97833.3 ± 1993.88486.4 ± 2112.2
Platelet count (1000/µL)Before269.07 ± 16.55294.38 ± 12.49300.57 ± 15.85294.14 ± 16.95
After278.13 ± 13.77286.09 ± 13.98279.86 ± 18.34280.09 ± 14.96
Urea (mg/dL)Before14.14 ± 6.0813.86 ± 4.2612.71 ± 3.9812.41 ± 3.23
After14.95 ± 3.8512.64 ± 4.0113.81 ± 4.2612.73 ± 3.34
Creatinine (mg/dL)Before0.88 ± 0.240.89 ± 0.180.87 ± 0.220.86 ± 0.21
After0.86 ± 0.140.88 ± 0.190.91 ± 0.250.89 ± 0.18
Uric acid (mg/dL)Before4.70 ± 1.374.90 ± 1.414.55 ± 1.804.33 ± 1.10
After4.58 ± 1.134.76 ± 1.394.78 ± 2.044.27 ± 1.48
Table 5.  Some variables in patients with active disease after 3 months supplementation (mean ± SD)
VariablesGroup P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
  1. BMI,  body mass index; group P, placebo; group C, conjugated linleic acids (CLAs); group E, vitamin E; group CE, CLAs + vitamin E.

  2. There were significant differences between groups after supplementation by ancova P < 0.01. Statistically significant differences between before and after: *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001. After supplementation, †group E had significantly higher levels than group P (P ≤ 0.01); ‡group CE had significantly higher levels than group P (P ≤ 0.001).

BMI (kg/m2)–0.18 ± 0.74–0.26 ± 0.88–0.82 ± 0.2.75–0.30 ± 0.78
Serum vitamin E (µg/mL)–0.39 ± 3.25–1.42 ± 6.65*–2.4 ± 3.78**†–2.62 ± 3.71***‡
Vitamin E intake (mg/day)–0.55 ± 1.20–0.91 ± 1.40–1.13 ± 1.43–1.22 ± 1.05

Although all forms of pain (morning, night and after activity) were reduced during the study in all groups, this reduction was not significant in group P (Table 6). Comparing the mean reduction both in groups C and CE showed significant difference against group P (P < 0.05). Morning stiffness increased in group P but decreased significantly in other groups (P ≤ 0.01) (Table 3). The difference was statistically significant between both groups C and CE compared with group P (P ≤ 0.05 and P ≤ 0.001, respectively). Both the number of swollen as well as tender joints decreased during the study period in all groups, but this was not significant in group P (Table 6). Comparing the difference, it was statistically significant only between groups C and P (P ≤ 0.05).

Table 6.  Clinical sign differences in patients with active disease after 3 months supplementation (mean ± SD)
VariablesGroup P
(n = 22)
Group C
(n = 22)
Group E
(n = 21)
Group CE
(n = 22)
  1. Group P, placebo; group C, conjugated linleic acids  (CLAs); group E, vitamin E; group CE, CLAs + vitamin E; DAS28, Disease Activity Score 28.

  2. There were significant differences between groups after supplementation for all above factors by ancova (P < 0.01). Statistically significant differences between before and after: *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. After supplementation †Group C has significantly lower levels than group P (P ≤ 0.05), ‡Groups C and CE had significantly lower levels than group E (P ≤ 0.01), §group CE had significantly lower levels than group E (P ≤ 0.001), ¶groups CE and C had significantly lower levels than group P (P ≤ 0.001), ††group C had significantly lower levels than groups P and E (P ≤ 0.05), ‡‡group CE had significantly lower levels than group E (P ≤ 0.05).

Morning pain (mm)7.73 ± 33.0823.39 ± 20.21†††6.43 ± 16.2940.23 ± 34.14d§
Night pain (mm)3.86 ± 29.3528.07 ± 29.96d14.29 ± 18.93**39.55 ± 28.62d¶‡‡
After activity pain (mm)0.68 ± 26.4734.41 ± 28.35d¶††11.43 ± 17.78**35.23 ± 26.52d¶‡‡
Morning stiffness (hour)–0.0.5a ± 0.860.68 ± 0.99**†–0.66 ± 1.11**0.82 ± 1.05**‡‡§
Number of swollen joints1.05 ± 7.746.63 ± 7.74***†2.62 ± 9.94**4.55 ± 5.39***
Number joints with tenderness0.68 ± 2.345.13 ± 6.34***†1.29 ± 5.84*2.46 ± 4.83***
DAS280.31 ± 0.981.93 ± 1.28***¶‡0.77 ± 0.91**1.80 ± 1.02***¶‡

DAS28 and PGA both improved in all groups, but was not significant in group P. In comparison between groups the differences were statistically significant (P ≤ 0.001) (Tables 3 and 6). Notably the difference was statistically significant between the mean changes of DAS28 both in groups C and CE compared with group P (P ≤ 0.001) (Table 6).

The levels of NSAIDs needed decreased significantly in the treatment groups (P ≤ 0.05) but not in the placebo group, and the difference between them and group P was statistically significant (P ≤ 0.001 for group C, P ≤ 0.05 for groups E and P ≤ 0.001 for group CE). The required doses of corticosteroids decreased only in group C (P ≤ 0.05) and group CE (P ≤ 0.01) (Table 2).

No significant changes were seen in the serum Hb, creatinine and uric acid levels, platelet count, RF titre and BMI during treatment in different groups. ESR decreased significantly in the three treatment groups. Comparison between groups showed significant differences between group CE and group P (P ≤ 0.05). Decrease in WBC count was significant in group CE (P < 0.05). The decrease in the CRP level was seen in all groups but was near significance level only in groups E and CE (Table 4) (P > 0.05). The serum level of α-tocopherol increased significantly in the groups E and CE in contrast to the placebo group (P ≤ 0.017, P ≤ 0.023 respectively) (Table 5).

No significant side effects were encountered. There were three reports of flatulence (2 in C group and 1 in CE group). It was relieved in two patients by prescribing tablets during meals instead of before meals, but drug cessation was required with one patient in group C (Fig. 1).

DISCUSSION

Conjugated linoleic acid, a naturally occurring fatty acid, was previously shown to alleviate clinical signs of inflammatory diseases such as atherosclerosis,37,38 type I airway hypersensitivity39,40 endotoxin-induced cachexia,41,42 lupus43,44 and models of inflammatory bowel disease.45,46 CLA reduces immune-induced TNFα and inducible COX-2 expression, key mediators of inflammation in RA. Based on previous works,47–51 it was hypothesized that dietary CLA would act as an anti-inflammatory agent in animal models of RA.47 It was shown that lipopolysaccharide (LPS) induced release of TNFα,42 inducible nitric oxide synthase,26 and antigen-induced release of eicosanoid products of COX-2;27 all were reduced by dietary CLA. Signalling pathways for TNFα and COX-2 such as peroxisome proliferator-activated receptor γ (PPARγ),48 PPARα,49 nuclear factor-κB (NFκB)50,51 and mitogen activator protein kinase (MAPK)52 have been implicated to be affected by CLA. Song et al. (2005) investigated the effect of dietary CLA supplementation (3 g/day; 50 : 50 mix of the two major isomers) on the immune system and plasma lipids and glucose of healthy humans (male and female) in a double-blind, randomized, reference-controlled study. A total of 28 healthy male and female participants aged 25–50 years received either high oleic sunflower oil (or 50% CLA 9–11 and 50% CLA 10–12 CLA isomers, 50 : 50 CLA-triglyceride form). A 12-week washout period followed the intervention period. 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-α and IL-β (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).17 In the Butz et al. study on the effect of CLA (mixed isomers of c9, t11, and t10, c12-CLA) on collagen antibody-induced arthritis (CIA), CLA-fed mice had arthritic scores 70% that of the corn oil (CO) fed mice.38 Previous experiments on systemic lupus erythematosus43,44 suggested the effects of dietary CLAs.

According to our knowledge, this is the first study showing the benefits of CLA (alone or in combination with vitamin E) in patients with RA as a type III hypersensitivity immune disorder.37 Three-month supplementation with CLA resulted in significant reduction in DAS28, joint pain and morning stiffness, WBC count, ESR, RF and CRP levels.

Our data about the effect of vitamin E in RA is more complete than other studies, because they did not determine the changing sign of diseases in humans. The Edmonds et al.9 study on clinical outcomes of RA showed the efficacy of vitamin E in patient-recorded morning pain, evening pain and pain after a chosen activity. This efficacy was supported by hematological and biochemical data gathered during the study period (3 weeks). Kolarz et al. (1990) compared vitamin E treatment with diclofenac in chronic polyarthritis. At 3 weeks, there were no statistically significant differences between groups in any of the seven clinical outcome measures. There were significant within-group changes in both groups in pain, morning stiffness, Ritchie Index and joint swelling as well as a high responder rate (81% for vitamin E and 75% for diclofenac). Pain VAS scores were significantly correlated with vitamin E serum concentrations.53 In a similarly designed study, Wittenborg et al. (1998) compared vitamin E and diclofenac treatment over 3 weeks in hospitalized chronic polyarthritis patients. Again, there were no significant differences between groups, but the authors reported significant within-group changes in both groups for all five clinical outcome measures. Physicians rated therapy successful in 54.8% of vitamin E group and in 48.8% of diclofenac group. Therapy was rated successful by patients in 54.8% of the vitamin E group compared with 53.6% of diclofenac group.54 These data show the effectiveness of vitamin E on pain and other clinical outcomes that verify our data.

Although CRP decreased in all groups, the changes in group E were more than other groups (P = 0.066). This may be due to higher levels of CRP at the baseline in this group.

CONCLUSION

It seems that CLAs decrease inflammation and improve clinical outcomes in patients with RA. Its combination with vitamin E, they could be helpful in increasing the anti-inflammatory effects of active RA.

ACKNOWLEDGMENTS

This study was funded through a research grant from the Research Deputy of Tehran University of Medical Sciences (with Proposal No., 2804). We are thankful for the cooperation of both Lipid Nutrition Company (Netherlands) for providing CLA capsules as Clarinol G-80, and Zahravi Company (Iran) for providing vitamin E pearls for this research.

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