Boston—Supplements, including vitamin D and omega-3 (or n-3) fatty acids, appear to have some beneficial effects when it comes to avoiding autoimmune diseases (ADs).

A study in BMJ suggests that people who took vitamin D and omega-3 fatty acids had a significantly lower rate of ADs, such as rheumatoid arthritis (RA), polymyalgia rheumatica, autoimmune thyroid disease, and psoriasis, than those who took a placebo.

Authors from Brigham and Women's Hospital in Boston point out that some preclinical studies have foreshadowed those supplements, including vitamin D and omega-3 (or n-3) fatty acids, might affect AD rates.

The latest study was a large-scale, randomized vitamin D and Omega-3 Trial (VITAL), which followed participants for approximately 5 years.

"It is exciting to have these new and positive results for non-toxic vitamins and supplements preventing potentially highly morbid diseases," stated senior author Karen Costenbader, MD, MPH, at Brigham and Women's Division of Rheumatology, Inflammation and Immunity. "This is the first direct evidence we have that daily supplementation may reduce AD incidence, and what looks like more pronounced effect after two years of supplementation for vitamin D. We look forward to honing and expanding our findings and encourage professional societies to consider these results and emerging data when developing future guidelines for the prevention of autoimmune diseases in midlife and older adults."

"Now, when my patients, colleagues, or friends ask me which vitamins or supplements I'd recommend they take to reduce risk of autoimmune disease, I have new evidence-based recommendations for women aged 55 years and older and men 50 years and older," Dr. Costenbader added. "I suggest vitamin D 2000 IU a day and marine omega-3 fatty acids (fish oil), 1,000 mg a day—the doses used in VITAL."

VITAL is a randomized, double-blind, placebo-controlled study of 25,871 men (aged 50 years and older) and women (aged 55 years and older) across the U.S. This study investigated whether taking daily dietary supplements of vitamin D3 (2,000 IU) or omega-3 fatty acids (Omacor fish oil, 1 gram) could reduce the risk for developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. Participants were randomized to receive either 1) vitamin D with an omega-3 fatty acid supplement, 2) vitamin D with a placebo, 3) omega-3 fatty acid with a placebo, or 4) a placebo only.

As part of an ancillary study prior to the launch of VITAL, researchers determined that they would also look at rates of ADs among participants.

"Given the benefits of vitamin D and omega-3s for reducing inflammation, we were particularly interested in whether they could protect against autoimmune diseases," said JoAnn Manson, MD, DrPH, co-author and director of the parent VITAL trial at Brigham and Women's.

As part of the study, participants completed questionnaires about new diagnoses of diseases, including RA, polymyalgia rheumatica, autoimmune thyroid disease, psoriasis, inflammatory bowel disease, and additional space to write in all other new onset ADs. Trained physicians reviewed patients' medical records to confirm reported diagnoses.

"Autoimmune diseases are common in older adults and negatively affect health and life expectancy. Until now, we have had no proven way of preventing them, and now, for the first time, we do," stated first author, Jill Hahn, ScD, postdoctoral fellow at Brigham and Women's. "It would be exciting if we could go on to verify the same preventive effects in younger individuals."

Results indicated that 123 participants in the vitamin D treatment group and 155 in the placebo group were diagnosed with confirmed AD (a 22% reduction). Among those in the fatty acid arm, confirmed AD occurred in 130 participants in the treatment group and 148 in the placebo group, which did not reach statistical significance, although the study found some evidence of effect after longer duration of supplementation.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.