Taking *these* for 5 years might reduce the occurrence of autoimmune disease by as much as 30%, the researchers found.
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We know that vitamin D scores an A-plus at helping maintain bone health (when you have enough, that is) and that higher levels of omega-3s are linked to a longer life, healthier heart and more body benefits. But about 40% of Americans are vitamin D-deficient, and a whopping 68% of adults don't consume enough omega-3 fats from their diet, according to expert estimates. (BTW, here are 5 sneaky signs you might not be eating enough omega-3s.)

We're now learning that taking supplements of both not only might deliver those wellness wins by helping you hit your quota for the day, but also may reduce risk for other types of diseases. Taking vitamin D and omega-3 fatty acid supplements for five years might lower the occurrence of autoimmune disease by 25% to 30% compared to those who didn't take supplements, according to new research presented at the American College of Rheumatology's ACR Convergence 2021.

A supplement bottle with a question mark on it on a background of pills
Credit: Getty Images / studiocasper / Tanja Ivanova

Earlier studies inspired this topic, says Karen Costenbader, M.D., M.P.H., the senior author of the research and the director of the Lupus Program at Brigham and Women's Hospital in Boston. The body can make its own vitamin D when exposed to sunlight, but many of us, particularly if we don't live in an area with ample sun or don't spend much time outdoors, need to get more vitamin D in food or through supplements. Before starting any new supplement, always consult your doctor to make sure it's right for you.

"In past ecologic observations, inflammatory bowel disease, multiple sclerosis and type 2 diabetes have been shown to be more prevalent at northern latitudes, where circulating vitamin D levels are lower. Both high plasma vitamin D and high residential UV exposure were associated with a decreased risk for rheumatoid arthritis among women in the Nurses' Health Study in our past work," she said at the conference. In short, this means that those who got vitamin D through the sun's rays and through food showed some protection against arthritis and inflammation. And regarding omega-3s, she said, "In past observational studies, lower rheumatoid arthritis risk has been observed in those with increased fatty fish intake." (Find out the healthiest fish to eat.)

Inspired by these findings, Costenbader and her team recruited 25,871 adults, with an average age of 67, to take part in their VITamin D and OmegA-3 TriaL (VITAL). The participants were randomly assigned to one of four groups to follow one of the following regimens daily for 5.3 years:

  • Take an omega-3 placebo and a vitamin D placebo
  • Take 1,000 milligrams of omega-3 fatty acids and 2,000 international units of vitamin D
  • Take an omega-3 placebo and a 2,000-IU vitamin D supplement, or
  • Take a 1,000-mg omega-3 fatty acid supplement and a vitamin D placebo

Each individual reported doctor-diagnosed autoimmune issues as they arose, if they did. At the end of the study, the rates of autoimmune disease (such as psoriasis, rheumatoid arthritis and more) were 25% to 30% lower for those who took either or both supplements compared to those who took only the placebos.

"The effect of vitamin D3 appeared stronger after 2 years of supplementation," the researchers say in their abstract. So even though the study ran for more than 5 years, you might reduce your risk well before then. "The more pronounced effect after 2 to 3 years of use with vitamin D makes sense biologically and supports long-term use," said Costenbader.

"Both vitamin D and omega-3 fatty acids have immunomodulatory and anti-inflammatory properties. Thus, our finding that vitamin D supplements, either alone or in combination with the omega-3s, reduce the risk of developing autoimmune disorders is biologically plausible and warrants further study," co-author and professor JoAnn Manson M.D., M.P.H., tells Medical News Today. "The findings are exciting because no other preventive therapies are available to reduce the risk of developing these serious health conditions."

While this is promising news, more research is needed to confirm these findings and to determine the ideal dose and time length of supplementation. That said, if you have a family history of autoimmune disease and think you might be falling short on vitamin D or omega-3 fats, it can't hurt to ask your doctor if you should get a blood test to check your current levels. If your doctor thinks supplements could be beneficial, Amazon sells third party-certified vitamin D and omega-3 supplements for under $20 each.

As always, before you begin any new supplement, be sure to consult with your doctor. And remember: Most supplements are totally unregulated—here's the #1 way to tell if they are safe.