Abstract
Purpose: Beneficial effect of long-chain ω-3 fatty acids against symptoms of rheumatoid arthritis (RA) has been indicated in previous studies. We examined the effect of flaxseed and anti-inflammatory diet in patients with RA. Methods: The 12-week intervention was performed on 120 patients with RA who were randomized to three groups of flaxseed (30 g/day) plus anti-inflammatory diet (AIF group), flaxseed (30 g/day) plus regular diet (RF group), and roasted wheat (30 g/day) plus regular diet (RW group). Disease Activity Score 28-joints (DAS28), health assessment questionnaire (HAQ) disability and pain, quality of life, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor, and anti-cyclic citrullinated peptides (anti-CCP) were measured before and after trial. Analysis was performed using per-protocol and intention-to-treat (ITT) approaches. Results: One hundred and two patients completed the protocol. Flaxseed decreased DAS28 in RF group compared to RW (- 0.87 ± 1.11 vs. – 0.24 ± 0.78; P = 0.014). Pain severity (P ≤ 0.001), morning stiffness (P < 0.05), and disease feeling (P < 0.01) decreased significantly in AIF and RF groups. HAQ disability and quality of life measurements improved in all 3 groups, with a greater extent in AIF and RF groups (P < 0.001) compared to RW. Between-group differences were significant for DAS28, pain scores, and physical and mental health variables. ESR, CRP, anti-CCP, and rheumatoid factor were not different between groups. Results of ITT analysis did not cause much difference. Conclusions: In conclusion, flaxseed may be used as a helpful adjuvant therapy for patients with RA. Calls are open for examining the effect of anti-inflammatory diet on RA symptoms.
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Key Points
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease in which antibodies of the immune system attack the synovium of joints. A number of meta-analyses have pointed to the inverse association between ω-3 fatty acids and RA development or the disease activity. Long-chain ω-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the main forms of ω-3 fatty acids examined in previous interventional studies. To delineate if α-linolenic also renders anti-inflammatory effects against RA, the effect of flaxseed in patients with RA was examined. In this study, the effect of flaxseed with and without the anti-inflammatory diet on disease activity, disability, pain, and quality of life in patients with RA was assessed. An intervention group with anti-inflammatory diet plus flaxseed was included to see if such treatment provides further protection over flaxseed alone.
The study showed promising results for the use of flaxseed as adjuvant therapy for patients with RA. The amount of α-linolenic acid in 30 g flaxseed is estimated about 6.8 g, which could produce approximately 340 mg EPA and 34 mg DHA in the body. This finding is particularly interesting because in a meta-analysis that reported the beneficial effect of long-chain ω-3 fatty acids on RA pain, much higher doses of EPA and DHA were used.
DAS28-ESR, pain severity, quality of life components including physical health and mental feelings, morning stiffness, and disease feeling decreased significantly in AIF and RF groups and HAQ disability index showed a more reduction in AIF and RF groups compared to RW (P = 0.051). These improvements occurred in the absence of effect on serum concentrations of inflammatory markers and autoantibodies (rheumatoid factor and anti-CCP). The results suggest that flaxseed as a good source of the progenitor of long-chain ω-3 fatty acids may also have protective effect against RA symptoms.
As inflammation is thought to be the cause of pain in RA, it seems paradoxical to see improvement in pain without reduction in inflammatory markers. However, various studies have found evidence that in RA, persistent activation of pain pathways may occur irrespective of the intensity of the inflammation or disease activity. RA patients may perceive pain independent of joint inflammation and thus treatments that target the pain itself could be effective.