The Omega-3 fatty acids found in certain fish can provide a possible protective benefit to individuals with rheumatoid arthritis and other related autoimmunity conditions. In fact, the benefit is strongest among those who have a genetic susceptibility to rheumatoid arthritis.
An Annals of Rheumatic Diseases study published in May, “Omega-3 fatty acids are associated with a lower prevalence of autoantibodies in shared epitope-positive subjects are at risk for rheumatoid arthritis,” found that people with the human leucocyte antigen class II genetic susceptibility are most likely to experience the positive result.
It’s the association between the n-3 fatty acids and anti-CCP2, the antibody that can pinpoint early rheumatoid arthritis development, as well as rheumatoid factor positivity, that supports the fatty acid’s ability to be protective, the study revealed. And, this work supports and furthers existing research, investigators said.
“Previous studies suggest n-3 [fatty acids] could possibly protect against the development of rheumatoid arthritis where our results suggest that the mechanism behind this might be through the prevention of autoantibody development,” they wrote. “More importantly, our results suggest the effect of longer-chain n-3 [fatty acids] on rheumatoid arthritis-related autoimmunity could depend on shared epitope status.”
Researchers recruited 2,166 participants from the Studies of the Etiology of Rheumatoid Arthritis (SERA) multi-center study, including those who didn’t have rheumatoid arthritis but were at-risk. They included two groups: first-degree relatives of persons with rheumatoid arthritis and parents of children with the allele for type 1 diabetes.
Each participant completed a 68-count joint exam and a questionnaire about environmental risk factors to evaluate the association between n-3 fatty acid supplement use and the prevalence of rheumatoid factor and anti-CCP2, the antibody that can pinpoint early rheumatoid arthritis development.
SERA participants were screened for shared epitope, the strongest predictor of seropositive rheumatoid arthritis. They were considered shared epitope positive if they a subtype of human leucocyte antigen-antigen D related 4 or –antigen D related 1 was present in their blood.
Investigators also conducted a 136-participant nested case-control study to understand the association between rheumatoid factor and anti-CCP2 positivity and n-3 fatty acid percentage in red blood cells.
According to results, in the shared epitope-positive group, rheumatoid factor cases are more likely to have lower levels of total red blood cell n-3 fatty acid percentage compared to the control group (OR 0.26, 95% CI 0.09 to 0.77, p=0.02). There was no association observed among the shared epitope-negative group.
In addition, data revealed an inverse association between anti-CCP2 positivity and the increasing total of red blood cell n-3 fatty acid percentage. (0.59, 95% CI 0.36 to 0.96) and the longer-chain n-3 fatty acids, eicosapentaenoic and docosahexaenoic acid (OR 0.56, 95% CI 0.34 to 0.92). The increasing total red blood cell n-3 fatty acid percentage was also inversely associated with anti-CCP2 positivity in shared epitope-positive participants (OR 0.44, 95% CI 0.21 to 0.93, p=0.03).
Based on questionnaire data, n-3 fatty acid supplement use was connected to a lower prevalence of anti-CCP2 in the shared epitope-positive group.
However, additional research is needed to study the interaction between n-3 fatty acids and shared epitope, as well as the progression of clinically-apparent rheumatoid arthritis. Doing so, investigators said, could offer insight into the group most likely to benefit from prevention strategies and how they are timed.