Vitamin D supplements and fish oil can reduce the risk of autoimmune diseases.

A randomized, placebo-controlled study of 25,000 older people found that those who took vitamin D, or vitamin D and omega-3 fatty acids, had a significantly lower rate of autoimmune diseases such as rheumatoid arthritis and psoriasis, compared with people who took a placebo.

More than 24 million people in the United States have an autoimmune disease

A normally functioning immune system helps prevent infection and disease, but in a person with an autoimmune disease, the immune system is overactive and mistakenly attacks the body's cells and tissues.

There are more than 80 known autoimmune diseases, including conditions such as multiple sclerosis, lupus, rheumatoid arthritis, and type 1 diabetes. About 5-8% of people, more than 24 million, in the United States are living with an autoimmune disease, according to the National Institute of Environmental Health Sciences (NIEHS).

Vitamin D and omega-3s linked to immune function

Experts don't know how autoimmune diseases occur; they are not contagious. A hereditary link is present in many autoimmune diseases, and it could be that a virus or environmental factor triggers the disease if a person already has the genes for it, according to the NIEHS.

There is evidence that some autoimmune diseases are related to vitamin D levels, and some autoimmune conditions, such as multiple sclerosis, are more common in northern latitudes, where vitamin D levels are, on average, lower due to low sun exposure, according to the National Multiple Sclerosis Society.

Several clinical trials, including a meta-analysis published in the Journal of Clinical Rheumatology, have shown that omega-3 fatty acids taken as fish oil supplements can improve symptoms of certain autoimmune diseases.

People who took vitamin D every day had a significantly lower risk of autoimmune disease

The original VITAL study was a randomized, double-blind, placebo-controlled trial of 25,871 people that examined the effects of vitamin D and omega-3 fatty acid supplementation on different types of cancer and cardiovascular disease, including heart attack and stroke . . Participants were 71% non-Hispanic white, 20% black, and 9% from other racial/ethnic groups; 51 percent were women and the average age was 67.1 years.

Before this study began, the researchers also planned to examine whether the supplements would have an impact on the number of people who develop autoimmune diseases as part of an ancillary study. After an average follow-up of 5.3 years, the researchers found the following results:

In patients randomized to receive vitamin D, 123 participants in the treatment group and 155 in the placebo group were diagnosed with confirmed autoimmune disease, a 22% reduction.

In the group that took a fish oil supplement or a placebo, autoimmune disease was confirmed in 130 participants in the treatment group and 148 in the placebo group. Although this was a 15% reduction, it was not enough to reach statistical significance. This means that although there was a reduction, it was not large enough for the researchers to be sure it was not caused by chance.

But the study found evidence of a greater effect of omega-3 fatty acid supplementation after a longer duration of supplementation.

The study is fascinating, says Elizabeth Bradley, MD, medical director of the Cleveland Clinic Center for Functional Medicine in Ohio, who was not involved in this research. "Researchers observed a significant decrease in the development of autoimmune diseases after vitamin D supplementation," she says.

At the Center for Functional Medicine, Dr. Bradley and a team of medical professionals lead groups for people with different types of autoimmune diseases.

“These findings are consistent with what we see in real life; we routinely check vitamin D and omega levels in people with autoimmune diseases, and I'd say 99% of the time they're low in both unless they're already taking a supplement or 'eat a diet high in oily fish,' she He says. .

Who should take a vitamin D or fish oil supplement and in what dosage?

Although these findings led Bradley to recommend d

It's a good idea to check with your doctor before taking any supplements, says Bradley. "We have to be careful with vitamin D supplementation because it's stored in our fat and can build up in the body," she says. Although not very common, taking very large doses can lead to toxicity, according to the National Institutes of Health.

Fish oil supplements can vary in quality, says Bradley. Your supplier may have suggestions on what to look for on the label, or you can research different brands on independent sites like ConsumerLab.com, which review and rate supplements.