Rheumatoid arthritis (RA) is a systemic, chronic inflammatory disease that affects 0.5% to 1% of the United States population.1 It is characterized by the swelling of synovial membrane tissue in the joints, morning stiffness lasting longer than an hour, and is typically a symmetrical polyarthritis.
Multiple studies2-14 have demonstrated that omega-3 fatty acid supplementation (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) results in improvement of the number of tender and swollen joints, duration of morning stiffness, physician and patient global assessment, grip strength, C-reactive protein (CRP) levels, and decreased use of non-steroidal anti-inflammatory drugs for patients with RA. The studies ranged from 14 to 67 patients who had a mean duration of RA of more than 10 years, over 12 to 52 weeks of supplementation, and varying dosages of EPA (1.7 – 4.6 g for 65 kg subjects) and DHA (0.18 – 2.5 g for 65 kg subjects).
For example, a 1994 double-blind randomized trial3 found that those who took 2.6 g/day of omega-3 supplementation had significant reduction in pain and improved grip. For 12 months, 60 RA patients were given either a placebo (n=20), 1.3 g/day fish oil (n=21), or 2.6 g/day fish oil (n=19). At 12 months, the 2.6 g/day fish oil group had a significant mean decrease of 61% (± 0.16, p<0.05) in the physician-assessed pain score and a grip strength increase of 25 mmHg (± 12, p<0.05). In the 2.6 g/day group 9 (47%) of patients were able to decrease their dose of NSAIDs, DMARDs, or both, while 85% of patients on placebo had to continue these medications at pre-study levels.
Anti-inflammatory foods with fish oil have also been found to ameliorate the symptoms of RA and disease activity.15 Sixty-eight patients with RA followed a normal Western diet or an anti-inflammatory diet (AID) of less than 90 mg/day omega-6 fatty acid (arachidonic acid) for eight months. In both groups, patients were given placebo or fish oil capsules (30 mg/kg body weight) for three months in a double-blind crossover study with a two-month washout period. Using the American College of Rheumatology (ACR) 66-joint count for swelling and 68-joint count for tenderness, the greatest improvements occurred in those taking fish oil on AID (37% improvement, p<0.001). At three months on fish oil, 38% of AID patients and 24% of patient on a Western diet achieved the ACR 20% improvement criteria (p<0.01).
A systematic review has shown that there are limited studies or no advantages on the benefits of vitamins A, C, E, ginger, or turmeric in patients with RA.16 A systematic review of randomized controlled trials (RCTs) showed no effect of turmeric (5 RCTs, n=356) or curcumin (14 RCTs, n=988) on inflammatory marker levels, including CRP, high-sensitivity CRP, interleukin-1, interleukin-6, and tumor necrosis factor.17
The National Institute Health recommends these sources of omega-3 fatty acids:18
- fish, such as salmon, mackerel, tuna, herring, and sardines
- nuts and seeds, such as flaxseed, chia seeds, walnuts
- plant oils, such as flaxseed oil, soybean oil, and canola oil
- fortified foods, such as some eggs, juices, milk, soy beverages, and infant formulas
A national survey also showed that omega-6 fatty acids are found in food already present and common in our diet such as chicken, potato and corn chips, nuts, and seeds.19
As the current evidence supports the benefits of omega-3 and omega-6 fatty acids supplementation, the Mediterranean diet (MD) may provide these extra nutrients that Western diets lack.20 The Mediterranean diet is an eating model based on the dietary patterns of countries surrounding the Mediterranean Sea.21 Its key components are its high monounsaturated/saturated fat ratio and high intake of plant-based foods. The MD incorporates seafood as a main source of protein, which provides omega-3 and omega-6 fatty acids. In a Swedish study22 of 51 patients with active RA with at least two years’ duration, 26 patients were randomized to the MD and 25 patients remained on an ordinary Western diet for 12 weeks. Patients on the MD diet had a decrease in disease activity index (DAS28) of 0.56 (p<0.001), improved physical function using the Health Assessment Questionnaire (HAQ) by 0.15 (p= 0.020), and an increase in vitality by 11.3 (p=0.018) measured by the quality of life survey (Short Form-36). The 0.15 improvement in physical function reaches close to the minimal clinically important difference23 of 0.22 on HAQ. However, the Mediterranean diet has not been shown to lower the risk of incident RA.24
- Smolen JS, Aletaha D, McInnes IB. Rheumatoid arthritis. Lancet 2016; 388 (10055): 2023-2038.
- Kremer JM, Lawrence DA, Petrillo GF, et al. Effects of high-dose fish oil on rheumatoid arthritis after stopping nonsteroidal antiinflammatory drugs. Clinical and immune correlates. Arthritis Rheum 1995; 38 (8): 1107-1114.
- Geusens P, Wouters C, Nijs J, et al. Long-term effect of omega-3 fatty acid supplementation in active rheumatoid arthritis. A 12-month, double-blind, controlled study. Arthritis Rheum 1994; 37 (6): 824-829.
- Lau CS, Morley KD, Belch JJ. Effects of fish oil supplementation on non-steroidal anti-inflammatory drug requirement in patients with mild rheumatoid arthritis--a double-blind placebo controlled study. Br J Rheumatol 1993; 32 (11): 982-989.
- Nielsen GL, Faarvang KL, Thomsen BS, et al. The effects of dietary supplementation with n-3 polyunsaturated fatty acids in patients with rheumatoid arthritis: a randomized, double blind trial. Eur J Clin Invest 1992; 22 (10): 687-691.
- Kjeldsen-Kragh J, Lund JA, Riise T, et al. Dietary omega-3 fatty acid supplementation and naproxen treatment in patients with rheumatoid arthritis. J Rheumatol 1992; 19 (10): 1531-1536.
- Skoldstam L, Borjesson O, Kjallman A, et al. Effect of six months of fish oil supplementation in stable rheumatoid arthritis. A double-blind, controlled study. Scand J Rheumatol 1992; 21 (4): 178-185.
- van der Tempel H, Tulleken JE, Limburg PC, et al. Effects of fish oil supplementation in rheumatoid arthritis. Ann Rheum Dis 1990; 49 (2): 76-80.
- Kremer JM, Lawrence DA, Jubiz W, et al. Dietary fish oil and olive oil supplementation in patients with rheumatoid arthritis. Clinical and immunologic effects. Arthritis Rheum 1990; 33 (6): 810-820.
- Tulleken JE, Limburg PC, Muskiet FA, et al. Vitamin E status during dietary fish oil supplementation in rheumatoid arthritis. Arthritis Rheum 1990; 33 (9): 1416-1419.
- Cleland LG, French JK, Betts WH, et al. Clinical and biochemical effects of dietary fish oil supplements in rheumatoid arthritis. J Rheumatol 1988; 15 (10): 1471-1475.
- Kremer JM, Jubiz W, Michalek A, et al. Fish-oil fatty acid supplementation in active rheumatoid arthritis. A double-blinded, controlled, crossover study. Ann Intern Med 1987; 106 (4): 497-503.
- Kremer JM, Bigauoette J, Michalek AV, et al. Effects of manipulation of dietary fatty acids on clinical manifestations of rheumatoid arthritis. Lancet 1985; 1 (8422): 184-187.
- Volker D, Fitzgerald P, Major G, et al. Efficacy of fish oil concentrate in the treatment of rheumatoid arthritis. J Rheumatol 2000; 27 (10): 2343-2346.
- Adam O, Beringer C, Kless T, et al. Anti-inflammatory effects of a low arachidonic acid diet and fish oil in patients with rheumatoid arthritis. Rheumatol Int 2003; 23 (1): 27-36.
- Rosenbaum CC, O'Mathuna DP, Chavez M, et al. Antioxidants and antiinflammatory dietary supplements for osteoarthritis and rheumatoid arthritis. Altern Ther Health Med 2010; 16 (2): 32-40.
- White CM, Pasupuleti V, Roman YM, et al. Oral turmeric/curcumin effects on inflammatory markers in chronic inflammatory diseases: A systematic review and meta-analysis of randomized controlled trials. Pharmacol Res 2019; 146: 104280.
- National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids. 2019; https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/. Accessed September 15, 2019.
- Reedy J, Krebs-Smith SM. Dietary sources of energy, solid fats, and added sugars among children and adolescents in the United States. J Am Diet Assoc 2010; 110 (10): 1477-1484.
- 2015 – 2020 dietary guidelines for Americans. 8 ed: U.S. Department of Health and Human Services and U.S. Department of Agriculture; 2015.
- Rees K, Takeda A, Martin N, et al. Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2019; 3: Cd009825.
- Skoldstam L, Hagfors L, Johansson G. An experimental study of a Mediterranean diet intervention for patients with rheumatoid arthritis. Ann Rheum Dis 2003; 62 (3): 208-214.
- Aletaha D, Smolen JS. Assessment of the patient with rheumatoid arthritis and the measurement of outcomes. In: Rheumatology. 7 ed. Philadelphia, PA: Elsevier; 2019:832-842.
- Hu Y, Costenbader KH, Gao X, et al. Mediterranean diet and incidence of rheumatoid arthritis in women. Arthritis Care Res (Hoboken) 2015; 67 (5): 597-606.