Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease

• Vitamin D regulates a wide array of genes involved in inflammation and immunity, and has been inconsistently associated with reduced risk of several autoimmune diseases in previous observational studies (1)
  • is an indisputable relation between vitamin D and the immune system (2)
    • with respect to in vitro, overwhelming evidence exists for a physiological role for the vitamin D system in immune regulation, and immune modulation can be observed by exposing immune cells to pharmacological doses of vitamin D metabolites
    • in animal models and humans, a correlation exists between adverse immune outcomes (infections and autoimmune diseases) and vitamin D deficiency
      
• Dietary marine derived long chain omega 3 fatty acids decrease systemic inflammation and ameliorate symptoms in some autoimmune diseases
  
• A randomised controlled trial (n=25,871 older adults, USA) (1) found that vitamin D (2000 IU/day) with or without omega 3 fatty acid supplementation (1000 mg/day) for five years reduced incident autoimmune disease compared with no supplementation (HR 0.78, 95% CI 0.61 to 0.99, p=0.05)
  • study authors concluded that:
    • vitamin D supplementation for five years, with or without omega 3 fatty acids, reduced autoimmune disease by 22%, while omega 3 fatty acid supplementation with or without vitamin D reduced the autoimmune disease rate by 15% (not statistically significant). Both treatment arms showed larger effects than the reference arm (vitamin D placebo and omega 3 fatty acid placebo)
    • clinical importance of these findings is high because these are well tolerated, non-toxic supplements, and other effective treatments to reduce the incidence of autoimmune diseases are lacking
      • also there were consistent results across autoimmune diseases and increasing effects with time

References:

• (1) Hahn J, Cook N R, Alexander E K, Friedman S, Walter J, Bubes V et al. Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial BMJ 2022; 376 :e066452 doi:10.1136/bmj-2021-066452.
• (2) Martens PJ, Gysemans C, Verstuyf A, Mathieu AC. Vitamin D's Effect on Immune Function. Nutrients. 2020;12(5):1248. Published 2020 Apr 28. doi:10.3390/nu12051248.