Association between Omega-3 fatty acids and autoimmune disease: Evidence from the umbrella review and Mendelian randomization analysis, 2024, Hong

Highlights

• Omega-3 fatty acids reduce disease risk, activity, and inflammation in SLE and RA
• Omega-3 fatty acids show potential benefits for autoimmune diseases such as psoriasis, type 1 diabetes, multiple sclerosis, juvenile arthritis, IgA nephropathy, Crohn's disease, and ulcerative colitis.
• Higher genetically predicted omega-6, LA, omega-6/omega-3 ratio levels, and MUFA are associated with an increased risk of autoimmune diseases such as RA, SLE, autoimmune thyroiditis, and alopecia areata.

Abstract
Background
Autoimmune diseases are a group of disorders characterized by abnormal immune responses that mistakenly target and attack healthy cells, tissues, and organs, resulting in inflammation and tissue damage. Omega-3 fatty acids possess anti-inflammatory activities and may decrease abnormal immune activity. However, the role of omega-3 fatty acids in various autoimmune diseases is still unclear. This umbrella review and Mendelian randomization (MR) study aims to summarize the highest available evidence on omega-3 fatty acids and autoimmune disease.
Methods
We conducted an umbrella review by searching electronic databases to identify systematic reviews and meta-analyses. The selection criteria included systematic reviews with or without meta-analysis, which evaluated omega-3 fatty acids as the exposure and autoimmune disease as the outcome variable. Two authors independently assessed the overlapping and quality of the reviews using the AMSTAR-2 tool. We also performed MR studies to investigate the potential causal effect of fatty acids on the risk of various autoimmune diseases, utilizing data from the meta-analysis of the UKB-TOPMed and FinnGen cohorts.
Result
The umbrella review identified 21 studies (8 systematic reviews and 13 meta-analyses) on 9 autoimmune diseases and 30 diseases in the MR study. AMSTAR 2 categorized the quality of evidence in six studies as critically low, six studies as low, eight studies as moderate, and one as high-quality evidence. The consistent result between the review and the MR study demonstrated the benefit of omega-3 fatty acids on rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Additionally, in our summary review, omega-3 fatty acids can improve disease activity and inflammation biomarkers; however, MR studies provided no consistent evidence for the causal effects of omega-3 fatty acids on psoriasis, multiple sclerosis (MS), type 1 diabetes (T1D), IgA nephropathy (IgAN), juvenile idiopathic arthritis (JIA), Crohn's disease (CD), and ulcerative colitis (UC).
Conclusion
The current study presented solid evidence highlighting the advantageous impact of omega-3 fatty acids on SLE and RA. This was achieved through the reduction of disease risk, the decrease of disease activity, and the mitigation of inflammatory biomarkers. To stratify another autoimmune illness, it is necessary to carry out rigorous evaluations to surpass the existing findings and enhance understanding in this domain.
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I just came across this paper ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10386285/ ) which makes the whole fatty acid debate more complex. There are different types of omega-3 acids (short and long, maybe other differences) which have different effects on the body. The author points out that increasing omega-3 intake can have harmful effects, and that it's better to reduce omega-6 intake. My guess is that it will turn out that in general a varied and moderate diet is better than trying to boost specific nutrients. Marketers would hate that.

 

I really benefitted from taking Omega 3 fish oils based on my RBC fatty test. My Omega 6 were at decent levels.