Most of us know Vitamin D is essential for the maintenance of normal bone and teeth, but it also plays an important role in supporting the immune system. Keeping the immune system healthy is very complex because the immune system has to be perfectly balanced. If there is not enough immune system activity, frequent infections can occur. If there is too much stimulation, autoimmune diseases can set in.

Low levels of vitamin D have been linked with both extremes, and low levels of vitamin D have been associated with worsening autoimmune diseases.