The Link Between Vitamin D and Autoimmune Disease
March 22, 2022
Vitamin D is a nutrient that has many roles within the immune system and central nervous system. For example, vitamin D benefits include having anti-inflammatory and immunoregulatory effects, in part by activating immune defenses and enhancing the function of immune cells (including T cells and macrophages).
Higher intake of vitamin D — both from natural sunlight and food sources, plus supplements — is believed to offer protection against infections, viruses and also certain immune-related disorders.
Can low vitamin D cause an autoimmune disease? Recent research suggests this might be a possibility.
Study: Vitamin D and Autoimmune Disease
A 2022 study published in the journal BMJ was conducted to determine whether or not vitamin D and omega-3 fatty acids could reduce autoimmune disease risk. The study was a randomized, double-blind, placebo-controlled trial that took place in the U.S. over the course of five-plus years and included more than 25,000 participants over the age of 50.
The study concluded:
Vitamin D supplementation for five years, with or without omega-3 fatty acids, helped reduce autoimmune disease by 22%.
Omega-3 fatty acid supplementation, with or without vitamin D, helped reduce autoimmune disease rate by 15%. (This was considered “not statistically significant.”)
Both treatments showed larger effects than placebos did.
Supplementation with both vitamin D and omega-3 fatty acids helped decrease autoimmune disease by about 30% compared to taking placebos.
Rheumatoid arthritis incidence was approximately 40% lower in the supplementation groups than in the placebo group.
The study was designed so participants received vitamin D supplements (1,25-dihydroxyvitamin D) in doses of 2,000 IU/day or matched placebos and omega-3 fatty acids (derived from marine sources) in doses of 1,000 mg/day or matched placebos. Participants self-reported all autoimmune diseases throughout the study, which were then confirmed by medical reviews.
Autoimmune diseases that were identified in participants included:
autoimmune thyroid disease
For the vitamin D arm, 123 participants in the treatment group compared to 155 in the placebo group had a confirmed autoimmune disease.
In the omega-3 fatty acids arm, 130 participants in the treatment group compared to 148 in the placebo group had a confirmed autoimmune disease.
Within the group receiving only placebos, 88 were confirmed to have developed autoimmune diseases. Among participants who received vitamin D and omega-3 fatty acids, 63 developed autoimmune disease, while 60 who received only vitamin D and 67 who received only omega-3 fatty acids had confirmed autoimmune diseases.
What It Means
The BMJ study described above revealed that higher vitamin D intake had the strongest effects on helping prevent autoimmune diseases. Omega-3s also lowered risk for autoimmune problems but not quite as well as vitamin D.
How does vitamin D help autoimmune diseases?
Autoimmune diseases are chronic conditions characterized by inflammatory autoimmune responses to self-tissues. In other words, they occur when someone’s own immune system starts attacking the body.
Vitamin D is thought to protect against autoimmune diseases via mechanisms such as:
Regulating an array of genes, many involved in inflammation
Suppressing inflammatory cytokines and chemokines (including C-reactive protein and IL-6)
Inhibiting B cell autoantibody production and promoting monocyte differentiation into macrophages (other ways to lower inflammation)
Increasing the production of anti-inflammatory regulatory T cells
Can vitamin D exacerbate autoimmune disease?
It’s unlikely, unless someone is taking very high amounts of vitamin D. As long as you follow guidelines, vitamin D should not worsen immune-related health problems.
How much vitamin D should you take if you have an autoimmune disease?
Aim for about 1,000 to 2,000 IU per day. In the study described above, adults were given 2,000 IU/day.
Remember to stay consistent, since the most protective effects were found after two years of supplementation.
Other Ways to Combat/Prevent Autoimmune Issues
Here are other tips for supporting your immune system:
Eat an anti-inflammatory diet to support gut health.
Pinpoint whether you may have allergies/intolerances, such as to gluten or dairy.
Reduce environmental risk factors, such as exposure to toxins, infections and stress.
Get enough sleep and rest.
Fight oxidative damage done by free radicals by avoiding smoking and too much alcohol.
What are the best vitamins for autoimmune diseases?
Experts believe that people with autoimmune diseases may benefit most from:
A quality multivitamin
Antioxidants, such as resveratrol (the same type found in berries and red wine)
Are omega-3s good for autoimmune diseases? Do omega-3s reduce inflammation?
Yes, as explained above, studies suggest higher intake of omega-3s may help protect against autoimmune disease development. It’s well-known that, generally speaking, omega-3 benefits can include fighting inflammation, supporting healthy blood flow and more.
That said, supplementation with omega-3s alone did not significantly lower incidence of autoimmune disease in the BMJ study. This means you should focus on making other healthy lifestyle changes too, including improving your diet and taking vitamin D as well.
On a positive note, other randomized, controlled trials of people with prevalent rheumatoid arthritis, systemic lupus and psoriasis have shown improvements in symptoms when they take omega-3s. For example, an observational study found a 49% reduction in rheumatoid arthritis risk for each 30-gram increase in daily fatty fish intake.
What supplements should I avoid if I have an autoimmune disease?
Be careful about using very high doses of vitamin C (too much isn’t always better), high doses of vitamin A/ beta-carotene and certain herbs on a long-term basis, such as echinacea and ginseng.
These may all be helpful short term or in moderate doses, but depending on your immune system and sensitivities, you might not benefit from them when taken for long periods.
Should I take vitamin D if I have an autoimmune disease? Research suggests that yes, you should.
A recent study found that vitamin D and omega-3 fatty acid supplementation had protective effects against autoimmune diseases (including rheumatoid arthritis, polymyalgia rheumatica, autoimmune thyroid disease and psoriasis).
In this large trial of older Americans, supplementation with vitamin D and omega-3s for five years were tied to a lower incidence of confirmed autoimmune disease compared to placebos.
A link has especially been found between low vitamin D and autoimmune disease development because vitamin D helps fight inflammation in multiple ways.
Does omega-3 suppress the immune system? No, omega-3s should help autoimmune disease symptoms in most cases, but you should still make lifestyle changes to support your immune system.