Vitamin D and Autoimmune Diseases

 

Autoimmune disease refers to problems with the immune system where immune cells target the body’s own healthy tissues by mistake, signaling the body to attack them. Autoimmune diseases can affect almost any part of the body. Some examples of common autoimmune diseases include rheumatoid arthritis, Type-1 diabetes, multiple sclerosis, psoriasis and lupus. There are over 80 known types of autoimmune diseases that affect over 24 million people in the US alone.

So recent study results published in The BMJ was good news. People who took 2,000 international units per day (IU/day) of vitamin D, with or without one gram of fish oil, for slightly more than five years reduced their risk of developing an autoimmune disease by 22% when compared to their counterparts who took a placebo.

"It looks like giving vitamin D will prevent autoimmune disease, which is really exciting," said study author Dr. Karen Costenbader, a rheumatologist at Brigham and Women's Hospital in Boston.

Participants were randomly assigned to receive either 2,000 IU/day of vitamin D with a 1 gram omega-3 fatty acid supplement; vitamin D with a placebo; omega-3 fatty acid with a placebo; or placebo alone. The participants then answered questionnaires about new diagnoses of autoimmune diseases, and doctors reviewed their records to confirm these diagnoses. People who took vitamin D or vitamin D and omega-3 fatty acids had a lower rate of autoimmune disease than people who took a placebo or omega-3 fatty acids alone after slightly more than five years of follow-up, and these effects were more pronounced after two years.

Still, Costenbader cautioned not everyone should jump on the vitamin D supplement bandwagon. "There are some people who need to avoid vitamin D because they have a history of kidney stones or other diseases," she said. "Check with your doctor before you start taking supplements."

Also, vitamin D is fat soluble, meaning it is not as easily expelled from the body as water soluble vitamins and can accumulate over time. The safe upper limit for supplementation with vitamin D is generally thought to be 4,000 IU daily.