In most cases (85–90%), bad breath originates in the mouth itself. The intensity of bad breath differs during the day, due to eating certain foods (such as garlic, onions, meat, fish, and cheese), obesity, smoking, and alcohol consumption. Since the mouth is exposed to less oxygen and is inactive during the night, the odor is usually worse upon awakening ("morning breath"). Bad breath may be transient, often disappearing following eating, brushing one's teeth, flossing, or rinsing with specialized mouthwash.
Bad breath may also be persistent (chronic bad breath), which is a more serious condition, affecting some 25% of the population in varying degrees.
Contrary to the popular legend that Listerine coined the term halitosis, it actually dates from the 1870s, combining the Latin halitus, meaning 'breath', with the Greek suffix osis often used to describe a medical condition, e.g., "cirrhosis of the liver". Bad breath is not, however, a modern affliction. Records mentioning bad breath have been discovered dating to 1550 B.C. A mouthwash of wine and herbs was one recommended way of solving the problem.
Low-carb diets may be good for your waistline, but you might not be able to say the same for your breath.
Low-carb lifestyle junkies are more likely to suffer from a seldom discussed side effect of such diets -- halitosis, aka bad breath. And since more than 25 million people say they have tried the Atkins diet (not to mention other low-carb eating plans), according to the National Marketing Institute, bad breath may be an epidemic!
Bad breath in the low/no-carb sect is often caused by certain chemicals that are released in the breath as the body burns fat. They are called ketones, and entering into a fat-burning state of ketosis is the hallmark of the Atkins diet. So the good news is that if your breath stinks, you're probably doing a good job of sticking to that low-carb diet.
"Carbohydrates aren't readily available, so you start to use other fats and proteins as your source of energy, and as a result you are going to get a breath problem," explains Kenneth Burrell, DDS, the senior director of the council on scientific affairs of the American Dental Association.
Scientists have long thought that smelling one's own breath odor is often difficult due to acclimatization, although many people with bad breath are able to detect it in others. Research has suggested that self-evaluation of halitosis is not easy because of preconceived notions of how bad we think it should be. Some people assume that they have bad breath because of bad taste (metallic, sour, fecal, etc.), however bad taste is considered a poor indicator.
For these reasons, the simplest and most effective way to know whether one has bad breath is to ask a trusted adult family member or very close friend ("confidant"). If the confidant confirms that there is a breath problem, he or she can help determine whether it is coming from the mouth or the nose, and whether a particular treatment is effective or not.
One popular home method to determine the presence of bad breath is to lick the back of the wrist, let the saliva dry for a minute or two, and smell the result. This test results in overestimation, as concluded from research, and should be avoided. A better way would be to lightly scrape the posterior back of the tongue with a plastic disposable spoon and to smell the drying residue. Home tests that use a chemical reaction to test for the presence of polyamines and sulfur compounds on tongue swabs are now available, but there are few studies showing how well they actually detect the odor. Furthermore, since breath odor changes in intensity throughout the day depending on many factors, multiple testing sessions may be necessary.
