I'm sorry for the delay in answer. I was just about to post it and somehow deleted the whole thing.
You ask an interesting question. Thank you.
In western medicine a white coated tongue can be caused by many different things. Some of them are smoking, alcohol consumption, candida, immunosuppression, and antibiotic therapy to name a few. Here is a link with more causes of a white coated tongue.
To treat this you need to find the cause. Quitting smoking, drinking alcohol, or even changing your mouthwash. If you are using a mouthwash with alcohol this can contribute to the problem. You can also try a tongue scrapper. You can but them at any drug store. Staying hydrated is also an important point. Your mouth is constantly being "washed out" by saliva. So it's important that your mouth is moist and you don't become too dehydrated or dry. If this occurs there can be a decline in saliva and overgrowth in bacteria.
Nearly all bad breath originates from the mouth, mostly from the surface of the tongue, below the gum line, between the teeth and other hard to reach areas. The mouth is normally inhabited by bacteria and the balance between the different kinds of bacteria determines the quality of your breath. The odor causing bacteria are anaerobic which means they cannot live in the presence of oxygen. These anaerobic bacteria inhabit the surface of the tongue by residing between the papillae of the tongue which is oxygen deficient i.e. they live "within" the tongue. These bacteria cannot be removed completely with a tongue scraper and will recolonize the mouth following antibody therapy. These naturally occurring bacteria feed on proteins (oral debris) and produce volatile sulfur compounds (VSC) as a by-product of metabolism causing the malodor of bad breath.
Here is a link with more information.
So help in curing bad breath brush and floss at least twice a day using a chlorine dioxide toothpaste, stay well hydrated, get regular cleanings, and avoid alcohol and smoking.
Let me know if you have any other questions!