We learned in school that sugar is neither an acid nor a base. It’s a neutral substance. So why does it corrode our teeth and cause cavities?
—Amanda Linden, Flagstaff, Ariz.
This is one of those questions to which you may not want to hear the answer! But here goes: Human mouths are home to hundreds of species of bacteria. (I know: Ugh.) One in particular ( Streptococcus mutans) feeds on carbohydrates. It excretes lactic acid as waste, and that acid is what eats into tooth enamel and creates cavities. So don’t blame your favorite treats! Just be sure to brush often.