Roughly two years ago, researchers at the Brigham and Women’s Hospital at Harvard University published initial findings of the VITAL study, a large-scale clinical trial which found that five years of treatment with vitamin D, omega-3s, or both each significantly reduced the risk of developing an autoimmune disease (AD).
 
Among study participants who agreed to be followed for another two years, the significant effects that vitamin D had on AD risk diminished to the point of being insignificant, however, those who took an omega-3s supplement either with or without vitamin D still had a significantly reduced AD risk after two years without treatment.  The follow-up findings to the VITAL trial were published in Arthritis & Rheumatology.
 
In the initial study on over 25,000 people ages 55 and older, vitamin D and omega-3s reduced the risk of autoimmune disease by about 30% versus placebo alone, the authors noted, and treatment with individual ingredients also resulted in risk reductions to a lesser extent. Vitamin D’s reduced AD incidence by 22%, while omega-3s had a non-significant reduction at the time. However, when applied to high-probability cases of AD, omega-3s did have a significant reduction of 18%.
 
Follow-up
 
In total, 21,592 (83.5%) of VITAL participants agreed to be followed for an additional two years.
 
After the two-year follow-up period, AD was confirmed in 255 participants who were randomized to vitamin D, versus 259 who took a vitamin D placebo. Meanwhile, AD was confirmed in 234 participants initially randomized to omega-3 fatty acids versus 280 randomized to its placebo.
 
“Two years after trial termination, vitamin D 2000 IU/day’s protective effects dissipated, but 1,000 mg/day omega-3 fatty acids had a sustained effect in reducing AD incidence,” the authors of the study confirmed.