We all know that a vitamin a day keeps the doctor away. Therefore, it wasn't shocking when a new study revealed that combining Vitamin D and Omega-3 fatty acids could reduce the risk of autoimmune diseases. Both supplements have some similar benefits. The American College of Rheumatology's ACR Convergence 2021 showed that people who take these nutrients over a long time lowered their chances of developing the autoimmune disease by 25 to 30%.