Vitamin D and omega-3 supplements reduce risk of autoimmune disease

3 minute read

A large US clinical trial has found that taking omega-3 and vitamin D3 supplements for five years reduced incident autoimmune disease by 25-30%.

A large US clinical trial has found that taking omega-3 and vitamin D3 supplements for five years reduced incident autoimmune disease by 25-30%.

The VITAL study, presented in plenary II of ACR21 by co-author Dr Karen Costenbader, randomised over 25,000 participants to one of four groups: vitamin D, omega-3, both or placebo. Participants were men over 50 and women over 55 who weren’t deficient in either nutrient or known to be at risk for autoimmune diseases.

Vitamin D has been found to play an important role in the modulation of inflammation and immune responses. Ecological and observational studies have suggested that deficiency is linked with autoimmune diseases including IBD, multiple sclerosis, type 1 diabetes, RA and Crohn’s disease.

Meanwhile, the anti-inflammatory effects of omega-3 fatty acids have been linked with reduced risk of inflammatory arthritis in observational studies.

There have been no prospective trials to test the effects of omega-3 or vitamin D supplementation on the incidence of autoimmune disease over time.

Participants in the VITAL trial reported annually on incident autoimmune diseases diagnosed by a doctor, with diagnoses confirmed by extensive medical record review.

The primary endpoint was total incident autoimmune diseases, including rheumatoid arthritis, polymyalgia rheumatica, psoriasis and psoriatic arthritis.

Over a median follow-up period of 5.3 years, confirmed autoimmune disease was diagnosed in 123 participants taking vitamin D3 and 155 in the placebo vitamin D group (HR 0.78, p=0.04). The difference when probable cases of autoimmune disease were added was non-significant.

If the first two years were excluded from the analysis – which Dr Costenbader said was reasonable, given that a lag in effect could be expected – the HR was 0.61 (p=0.005).

For omega-3 supplementation, the difference was non-significant for confirmed autoimmune diseases (HR=0.85, p=0.20), but when probable cases were included, the HR was 0.82 (p=0.04). Among participants with a family history of autoimmune disease, there was a stronger effect (p=0.03) for confirmed cases.

In terms of the four trial arms, the HR for vitamin D alone vs placebo was 0.68 (p=0.02); for omega-3 alone it was 0.74 (0.07); and for vitamin D and omega-3 combined was 0.69 (p=0.03).

The trial has been extended for further follow-up.

The authors stated that the clinical importance of the study is high, given that these are well-tolerated, non-toxic supplements and that there are no other known effective therapies to reduce incidence of autoimmune diseases.

  • 0957 Vitamin D and Marine n-3 Fatty Acid Supplementation and Prevention of Autoimmune Disease in the VITAL Randomized Controlled Trial

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