Omega-3 Fatty Acids, Rheumatoid Arthritis, and Inflammation
At TalkingNutrition, we like to stress the importance of a balanced diet that contains recommended levels of nutrients in maintaining health. In some cases, dietary components can in fact be used to treat a disease when supplied at levels that are unlikely to be achieved through normal intakes. A good example of this is found in a publication by Denman. The author described a study in which patients with early rheumatoid arthritis were supplied with high and low levels of fish oil. Rheumatoid arthritis is a chronic disease that causes joint stiffness initially, but later can deform joints and cause chest pain and involve other organs. It is an autoimmune disease that is linked to excessive levels of inflammation; this means that the immune system attacks healthy tissue by mistake.
The most widely studied bioactive components in fish oil are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These long chain polyunsaturated fatty acids have various effects in the body. In the immune system, EPA is a precursor for eicosanoids, which are messenger molecules that are less inflammatory than those produced by omega-6 fatty acids (see Miles and Calder’s review). EPA and DHA also produce anti-inflammatory molecules called resolvins (Norling and Peretti), and reduce the expression of genes that produce inflammatory components (Calder). As rheumatoid arthritis is caused by inflammatory molecules attacking healthy cells, reducing inflammation can treat the cause of the disease.
The current study used a low dose of 0.4 grams per day, which is able to be obtained through the diet, and a high dose of 5.5 grams per day. Patients who had been diagnosed with rheumatoid arthritis for less than one year were asked to participate in the study. The progression of rheumatoid arthritis, including joint deformities, can be delayed if treatment is started early to reduce the excessive amounts of inflammatory molecules in the body. The fish oil treatment was additional to the use of a single first-line disease-modifying anti-rheumatic drug (DMARDs). The patients were guided by physicians during the one-year study.
After one year of supplementation, the authors found that patients in the high-dose group had a lower failure rate of first-line treatment. In the high-dose group, only 10% reported a failure of DMARDs, while in the low-dose group, 32% reported DMARD failure. This meant that for around one quarter of patients, fish oil supplementation and the first-line treatment were enough to stabilize rheumatoid arthritis, and for a further two thirds, the first-line treatment was likely sufficient.
These results agree with other meta-analyses on the effect of omega-3 fatty acids on rheumatoid arthritis. For example, Lee, Bae and Song analyzed ten clinical trials in rheumatoid arthritis patients and found that omega-3 supplements significantly reduced the use of common painkillers. Trials also found a non-significant reduction in the number of tender and swollen joints, improvements in physical function, and less joint stiffness in the morning. The dose should be at least 2.7 grams per day, and the supplements should be taken for longer than 3 months. Rontoyanni and co-workers also speculate that this high supplementation regimen can also reduce the likelihood of cardiovascular disease occurring in rheumatoid arthritis patients.
So there we have it. Omega-3 fatty acids in doses that can be obtained by the diet reduce risk of cardiovascular disease. In higher doses, they can be used as an adjunct to medication for rheumatoid arthritis.
Denman M. In patients with early rheumatoid arthritis, fish oil reduced failure of treatment with DMARDs. Annals of Internal Medicine. 2014 Feb;160(4):JC11.
Calder PC. Omega-3 polyunsaturated fatty acids and inflammatory processes: nutrition or pharmacology? Br J Clin Pharmacol. 2013 Mar;75(3):645-62. doi: 10.1111/j.1365-2125.2012.04374.x. http://www.ncbi.nlm.nih.gov/pubmed/22765297
Miles EA, Calder PC. Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis. Br J Nutr. 2012 Jun;107 Suppl 2:S171-84. doi: 10.1017/S0007114512001560. http://www.ncbi.nlm.nih.gov/pubmed/22591891
Norling LV, Perretti M. The role of omega-3 derived resolvins in arthritis. Curr Opin Pharmacol. 2013 Jun;13(3):476-81. doi: 10.1016/j.coph.2013.02.003. Epub 2013 Feb 21. http://www.ncbi.nlm.nih.gov/pubmed/23434193
Rontoyanni VG, Sfikakis PP, Kitas GD, Protogerou AD. Marine n-3 fatty acids for cardiovascular risk reduction and disease control in rheumatoid arthritis: "kill two birds with one stone"? Curr Pharm Des. 2012;18(11):1531-42. http://www.ncbi.nlm.nih.gov/pubmed/22364137