I think it has more to do with what you eat and keeping inflammation at a minimum. I think when you expose your body to things it doesn't like you cause inflammation response and more susceptible to cancer, colds, flu, illness, etc. Also - drinking Kombucha tea helps me anyways. Most immune system in GI tract, keep that healthy and happy and you should be happy and health too. That's what has worked for me anyways. Coming from former compromised immune system anon.