Vitamin D3 plays a significant role in regulating immune responses and supporting immune cell activation. Adequate vitamin D levels may help the body maintain a balanced defense against infections. Vitamin K2 is also associated with mechanisms that may influence inflammatory balance in the body. When taken together, vitamin D3 and K2 may provide complementary support for immune function. Some studies suggest that maintaining healthy vitamin D levels can contribute to improved resistance against infections. However, immune health depends on many factors including balanced nutrition, sleep quality, and overall lifestyle habits.