Vitamin D and Fish Oil Supplements May Reduce Risk of Autoimmune Disease – Rheumatoid Arthritis, Psoriasis, and Thyroid

With a more pronounced effect after two years of supplementation.

Taking daily vitamin D supplements — or a combination of vitamin D and omega-3 fish oil — appears to carry a lower risk of developing autoimmune disease, with a more pronounced effect after two years, finds a trial of older US adults published by The BMJ today (January 26, 2022).

The researchers say the clinical importance of these findings is high, “given that these are well-tolerated, non-toxic supplements, and that there are no other known effective therapies to reduce rates of autoimmune diseases.”

Autoimmune disease happens when the body’s natural defense system mistakenly attacks normal cells. Common conditions include rheumatoid arthritis, psoriasis, and thyroid diseases, which increase with age, particularly among women.

Both vitamin D and omega-3 fatty acids derived from seafood are known to have a beneficial effect on inflammation and immunity, but no large randomized trials have tested whether these supplements can lower the risk of autoimmune disease.

So researchers set out to test the effects of vitamin D and omega-3 fish oil supplements on rates of autoimmune diseases in 25,871 US adults (average age 67; 51% women; 71% non-Hispanic white).

When they joined the trial, participants provided information on their age, ethnicity, region of residence, income, education, lifestyle, weight, medical history, diet, and supplement use. Blood levels of vitamin D and omega-3 fatty acids were also measured.

Participants were then randomly allocated to receive vitamin D (2,000 IU/day) or matched placebo, and omega-3 fatty acids (1,000mg/day) or matched placebo, and were asked to report any diagnosed autoimmune disease over an average 5.3 year period. 

These included rheumatoid arthritis, polymyalgia rheumatica (pain and stiffness in the muscles around the shoulders, neck, and hips), thyroid disease, and psoriasis, among others. 

Reported cases were confirmed using medical records. Those with insufficient documentation for certainty were classed as “probable” cases.

Over the full duration of the trial, a confirmed autoimmune disease was diagnosed in 123 participants in the vitamin D group compared with 155 in the placebo group — a 22% lower relative rate.

In the omega-3 fatty acid group, 130 confirmed cases were diagnosed compared with 148 in the placebo group (a 15% reduction), but this was not a statistically significant result.

However, when probable cases were included, omega-3 fatty acid supplements did significantly reduce the rate by 18% compared with placebo and there was a significant interaction with time, indicating a stronger effect the longer supplements were taken.

Similar results were found when only the last three years of the trial were considered. The vitamin D group had 39% fewer confirmed cases than placebo, while the omega-3 fatty acid group had 10% fewer confirmed cases than placebo. Both vitamin D and omega-3 fatty acid supplements decreased autoimmune disease by about 30% versus placebo alone. 

This was a large trial involving a diverse general population with high rates of follow-up and adherence to treatment. However, the researchers acknowledge that they tested only one dose and formulation of each supplement, and say the results may not apply to younger individuals.

Nevertheless, they say this is the first direct evidence that daily supplementation with either agent — or a combination of vitamin D and omega-3 fatty acids — for five years among older US adults reduces autoimmune disease incidence, with more pronounced effect after two years of supplementation.

“We are continuing to follow participants for two years in an extension study to test the time course of this autoimmune disease reduction effect,” they write. “Further trials could test these interventions in younger populations, and those with high autoimmune disease risk.”

Reference: “Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial” by Jill Hahn, Nancy R Cook, Erik K Alexander, Sonia Friedman, Joseph Walter, Vadim Bubes, Gregory Kotler, I-Min Lee, JoAnn E Manson and Karen H Costenbader, 26 January 2022, The BMJ.
DOI: 10.1136/bmj-2021-066452

Autoimmune DisordersBMJNutritionPopularSupplementVitamins
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  • Slavi Stubler

    At 76, I CONFIRM that this is 150% correct. Under a treat for last few years with joints pain, I cured my self with Omega-3, 2000 IU of Vit.D and B12. For last two years I do NOT have any ills and NO meds. You do have to take a proper dose in order to work for you. I also do my own studies of vit. world for last 35 years.
    Thank you to vitamin studies and producers!

  • Henry

    Neat trick Slavi, doing 35 years worth of research on a domain that was registered 6 years ago. Way to spam and avoid the filters d bag.

    • Slavi Stubler

      I did NOT say I have researched the domain! I have researched(ing) the vitamins. Sloppy reader.

  • Henry S Jeleniewicz

    Having psoriasis 42 years I noticed my skin improved when I started taking vitamin d3 because of covid. Also I discovered many users ago taking lecithin pills also lessens my psoriasis.

  • M T

    My D levels had tested low at one point, so I started talking a supplement. I was also taking fish oil and a few others. At one point I stopped taking my supplements, and I started experiencing symptoms of weight loss, tremors, and a goiter. I was diagnosed with a autoimmune thyroid disorder – Graves’ Disease. Autoimmune disorders run in my family, but I think my low vitamin D may have been a trigger.

  • Barbara Jean

    What about emu supplements instead of fish oil?

  • Rich

    I have been taking omega 3 fish oil supplements for 4 years now.. I have been taking vitamin D3 with K with K2 also.. Not only has it helped me with with fending off illnesses I also have a better overall overall well being and I sleep better and my mood is better so I highly recommend you do both

  • Steve J.

    Well…it hasn’t helped me.
    I have been taking high strength cod liver oil tablets for years, and so far I have had Lycomplanus, Rosacea, and I also have Coeliac disease too…all auto-immune diseases, so that makes a mockery of that really

  • Dr SH Vilane

    Vitamin D has been scientifically proven in many metabolic reactions in the human body.But,remember nutrition is not Newtonian. Far more ,nutrition for optimum health outcomes is more like quantum physics.What happens when you deficient in 3,4,6,11 etc of tge essential nutrients??All of the 42 essential nutrients are of the same potency. Non is greater than the other. One cannot replace the other.All are essential!

  • Ali dib Karam

    They never take a selfie..its not working