In a study that spanned over five years, scientists in the US found that providing older subjects with vitamin D or Omega-3 fish oil supplements resulted in a lower rate of autoimmune disease, especially after two years of taking the supplements.
Taking daily vitamin D supplements, or a combination of vitamin D and Omega-3 fish oil, may help protect older adults from developing autoimmune disease. Researchers write in the peer-reviewed journal BMJ that the effect is even more pronounced after two years.
The researchers place a great importance on these findings, as “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 immune system that is supposed to defend it from foreign cells cannot tell the difference between your own cells vs foreign cells, and attacks normal cells.
There are more than 80 types of autoimmune diseases, such as rheumatoid arthritis, psoriasis, psoriatic arthritis, lupus, and thyroid diseases including Graves’ disease (hyperthyroidism) and Hashimoto’s thyroiditis (hypothyroidism).
Autoimmune diseases increase with age, and particularly affect women. The study’s authors write that they are “the third leading cause of morbidity in the industrialised world, and a leading cause of mortality among women.”
Autoimmune diseases don’t have proper, effective treatments, causing much pain and discomfort as well as “major societal and economic burdens.”
The researchers note that vitamin D and marine-derived, long-chain Omega 3 fatty acids are two supplements they are investigating as potential autoimmune disease treatments. Both supplements are known to have a beneficial effect on inflammation and immunity, but there hadn’t been any large randomised trials conducted whether they can, alone or together, lower the risk of autoimmune disease.
The randomised, double blind, placebo controlled, two-by-two factorial design trial was meant to test the effects of vitamin D and Omega-3 fish oil supplements on rates of autoimmune diseases in 25,871 adults. Of the participants, 51 percent were women, 71 percent were non-Hispanic white. There were 5,106 Black participants (20 percent). Their average age was 67.
The study asked for participants’ age, ethnicity, region of residence, income, education, lifestyle, weight, medical history, diet and supplement use. The researchers also measured participants’ levels of vitamin D and Omega-3 fatty acids.
The researchers then randomly assigned participants to a group to receive vitamin D (2,000 IU/day) or matched placebo, and Omega-3 fatty acids (1,000mg/day) or matched placebo. The participants were then asked to report any diagnosed autoimmune disease over an average 5.3 year period.
The autoimmune diseases included “rheumatoid arthritis, polymyalgia rheumatica (pain and stiffness in the muscles around the shoulders, neck and hips), thyroid disease, and psoriasis, among others.”
The researchers confirmed the reported cases using medical records, and those with insufficient documentation for certainty were classed as ‘probable’ cases, a news release notes.
In the vitamin D group, there were 123 participants who were diagnosed with a confirmed autoimmune disease over the full duration of the trial, as opposed to 155 in the placebo group – a 22 percent lower relative rate.
In the Omega-3 fatty acid group, there wasn’t a statistically significant result, with 130 confirmed cases as opposed to 148 in the placebo group (a 15 percent reduction).
Yet when the probable cases were also taken into account, Omega-3 fatty acid supplements “did significantly reduce” the rate by 18 percent compared with placebo and there was a significant interaction with time, suggesting a stronger effect the longer supplements were taken.
The researchers then looked at the last three years of the trial, two years after participants started taking supplements or placebos.
The vitamin D group had 39 percent fewer confirmed autoimmune disease cases than the placebo group. The Omega-3 fatty acid group had 10 percent fewer confirmed cases than the placebo group.
The authors wrote in the study that “In this two-by-two trial, supplementation with both vitamin D and omega 3 fatty acids decreased autoimmune disease by about 30 percent versus placebo alone.”
The authors say that the strengths of this trial “include a large, diverse general population sample; high rates of follow-up and adherence to the trial regimen; validated biomarkers of regimen adherence; and rigorously defined autoimmune disease endpoints.”
They are also quick to point out that because the participants were older adults, the results “might not generalise to autoimmune diseases that primarily have their onset in younger people,” yet note that the emergence of many of the specific autoimmune diseases observed, such as rheumatoid arthritis and psoriasis, is similar in younger adults.
They also admit that the trial tested only one dose and formulation of each supplement, and that confirming diagnosis of autoimmune thyroid disease based on medical records was a “challenge”.
The researchers say “longer follow-up could be informative,” and that they are following up on participants in an open label extension study.
“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.”