system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Were our teeth naturally supposed to be yellow? And is it actually healthy for them to be white?
gpt
Enamel is white, and it covered Dentin, which is yellow. As bacteria and acids eat away at enamel, yellow dentin is exposed. Teeth would have naturally been very white up until processed sugars because widespread, because bacteria thrive on sugar and churn out acids which break down enamel.