While no single meat can be considered the absolute best for the immune system, certain types can provide nutrients that support immune function. Here are a few examples: Poultry (such as chicken and turkey) Fish (like salmon, tuna, and mackerel) Lean beef Pork  However, keep in mind that even though they improve the immune system, you should eat a variety of foods. Such as fruits, vegetables, whole grains, and other protein sources as they play a significant role in supporting immune function. Additionally, cooking methods retain nutrients, and not overeating fat or sodium can significantly help your overall health.