Immune response is compromised by poor nutrition. While the relationship between nutrients and immunity is complex and not always clear, zinc, copper, iron and selenium are minerals that have been identified by research as needed for the immune system to function properly. Increasing intake of these minerals through diet and supplementing could enhance immune function.  However, one challenge is that excess amounts of these minerals can also impair immune function and create other mineral deficiencies. For example, too much zinc can lower both copper and magnesium. So how do you find the balance of nutrients that is right for you?...