Autoimmune diseases are severe inflammatory conditions, rheumatoid arthritis is one of them.
The body’s immune system starts to attack its own tissue which is a big problem. Decreasing the risk for that to happen would be a very big help.
The following study which went on for 5.3 years and included 25 871 participants divided into several groups and either supplemented with vitamin D 2000 IU per day, omega 3 fish oil 1000 mg per day, both vitamin D and omega 3 fish oil, or a placebo supplement (Hahn J, et.al., 2021).
The results showed supplementation with both vitamin D and omega 3 fatty acids decreased autoimmune disease by about 30% compared to the placebo.
Rheumatoid arthritis incidence was approximately 40% lower in the supplementation groups than in the placebo groups.
Both supplementation with vitamin D and omega 3 fish oil individually was effective, but the combination of both worked the best.
Reference
Jill Hahn, Nancy R Cook, Erik K Alexander, Sonia Friedman, Joseph Walter, Vadim Bubes, Gregory Kotler, I-Min Lee, JoAnn E Manson, Karen H Costenbader Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial, Clinical Trial BMJ. 2022 Jan 26;376:e066452.