Two years after the end of a randomized trial that showed a benefit of daily vitamin D and omega-3 fatty acid (n-3 FA) supplementation for reducing risk for autoimmune diseases, the salubrious effects of daily vitamin D appear to have waned after the supplement was discontinued, while the protection from n-3 lived on for at least 2 additional years.
As previously reported, the randomized VITAL, which was designed primarily to study the effects of vitamin D and n-3 supplementation on incident cancer and cardiovascular disease, also showed that 5 years of vitamin D supplementation was associated with a 22% reduction in risk for confirmed autoimmune diseases, and 5 years of n-3 FA supplementation was associated with an 18% reduction in confirmed and probable incident autoimmune diseases.