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

Last edited 05/2022 and last reviewed 05/2022

  • 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

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