What you do to your mind you do to your body and what you do to your body you do to your mind. The major controller is the mind because most of your choices are coming from your mind. These can be food choices along with many others. If you carry conscious and subconscious stress programs this is going to suppress immune function and eventually make your body sick. But also a person that drinks coffee, eats a lot of sugar and relies on other stimulants is also going to induce some immune dysfunction that will affect the body.