question for the OP... do you chew your food well or do you have a tendency to scarf down food fast with larger chunks getting into your digestive system?
I am a 'scarfer' and also have a slight coated tongue. I theorize that stuff is putrefying in the intestines when I do that, since stomach acid will break down smaller chunks of food far more effectively then larger chunks.
Also, I've read integrating saliva into the food helps the body not recognize it as an invader which sets off a histamine response, but rather as part of the body's fluids.
I haven't gone long enough chewing well to have any sort of results from it, my scarfing mentality takes over. I may change that if I hear you scarf your food down though. :)