Checkup.(Life - Health)

Fresh air

Breath mints, breath strips, mouthwash, toothpaste. It's a multibillion-dollar-a-year industry. Why? Because bad breath leaves a bad impression. But the truth is, it could also be a sign of bad health.

"Bad breath could be because of a problem in the sinuses, mouth, lungs, kidney or airways," says Dr. Prabhakar Swaroop, a gastroenterologist at St. Louis University Hospital. "If someone comes to me with persistent bad breath, I start looking for other causes of it."

Here's the lowdown on bad-breath myths and facts.

Myth: Low-carb diets don't cause bad breath.

Fact: Because you consume so much protein in low-carb diets, this protein is food for the anaerobic bacteria that cause bad breath. Certain chemicals, called ketones, are released in the breath as the body burns fat. There are only two ways to excrete ketones, …