DEAR DOCTORS: Our nine-year-old loves science and has become obsessed with saliva. He recently learned in school that it helps prevent disease, and now he wants to know more. My wife and I are glad he's curious and hope you can help. What is saliva? Does it really help people stay healthy?
DEAR READER: Your budding scientist has asked a great question. When you think about the many ways our bodies protect us from potential danger, saliva isn't the first thing that generally comes to mind. And yet, it's a crucial line of defence. It makes sense, considering the mouth is a key entryway for potential pathogens. These include dangerous microorganisms or toxins that may be contained in food or drink, as well as those that can hitch a ride into the mouth on fingers, surfaces, objects or even a kiss. And while we rarely think about the constant presence of saliva in our mouths, it's actually a pretty remarkable substance.
