Dairy foods are one method to receive some of the critical nutrients you need for good immune function as part of a healthy diet. The immune system serves as the body’s first line of defense, defending you against infection.itamin A, vitamin D, protein, selenium, zinc, B6 (pyridoxine), and antioxidants such as vitamins C and E are all essential for immune support. These nutrients can be obtained by When people say they want to strengthen or boost their immunity, what they’re really asking is, “How can I keep my immune system as strong as possible so I don’t get a cold, the flu, or something more serious like COVID-19?” We all don’t want to get sick. It is critical to have a robust immune system in order to stay healthy.