This isn't a science article but I didn't know where else to put it and I bet if I took a minute I could find an article to go with it
Back when I was drinking I took my mom to a Chinese doctor for her RA ...while waiting the doctor asked to see my tongue....after looking at it she asked if I smoked and drank ...I answered yes...a little (hahahaha)...she told me to stop.
The Chinese can tell your basic health from your tongue...I always remembered that afterwards....as I got worse my tongue looked worse no matter what I did. Its now jpink and healthy looking...but sometimes when I am talking to someone I will notice their tongue looks like mine used to and I will wonder about them.