Vitamin D plays a critical role in immune health by modulating the immune response. It enhances the pathogen-fighting effects of monocytes and macrophages — white blood cells essential for combating infections. Adequate levels of vitamin D can also help reduce the risk of autoimmune diseases. Additionally, it promotes the production of antimicrobial peptides, which contribute to the body’s defense mechanisms. Therefore, maintaining optimal vitamin D levels is crucial for a well-functioning immune system.