boost your immunity

All the magazines lately seem to have articles on boosting immunity.  Some tips from the latest Real Simple magazine.
:eat less fat:
:exercise:
:eat protein:
:sing or play music:
:maintain your weight:
:pet your puppy (or cat):
:get lots of fruit and veggies:
:take up some relaxation habits:
:eat good bacteria:
:get enough sleep:
How are you doing on these things?
Also – has anyone ever tried [...]