 According to the American Dental Association, about 50% of American adults suffer from oral malodour, with prevalence rates around the world ranging from 2% to nearly 80%. On average, it seems to be about 1 in 3 of us on the planet Earth have bad breath. What effect might stress have on the smell of our breath? Stress students were found to have significantly higher levels of the rotten egg gas hydrogen sulfide, which is one of the main volatile sulfur compounds related to bad breath, originated from the degradation of the sulfur-containing amino acid cysteine found concentrated in animal proteins like meat and dairy. Were they eating different diets or just too busy to brush? The simplest explanation is just the dry mouth you get when you're super stressed, part of our fight-or-flight response. It's the same reason we get morning breath, because we have decreased saliva production when we sleep that would otherwise self-clean the mouth, keeping it from becoming like a stagnant pond. Though maybe stress hormones are having an effect as well. We suspect sex hormones may play a role, since though men and women have the same before-and-after rise in bad breath compounds after a stressful situation, women seem to start out with higher baseline levels. Gender appears to play an important role. Women have significantly worse morning breath, for example, and bad breath is affected by the menstrual cycle. In fact, that's listed as one of the causes, so-called menstrual breath. As you can see, there are higher levels of bad breath compounds in the mouths of women in the premenstrual and menstrual phases, compared not just to men, but the follicular phase of their own cycle, meaning like the first half before ovulation. Hmm, so maybe bad breath is a hormonal thing, more than just a dry mouth thing? But salivary flow is also lower in menstrual and premenstrual phases. Check it out. Significantly less salivary flow during menstrual flow and right before. So is this all just about having a dry mouth during stress in certain times of the month? How could you tease out the effects? Well, what about studying stressful periods? PMS, premenstrual syndrome, is a stressful state characterized by irritability, tension, mood swings. Is the menstrual dry mouth and bad breath just due to period stress? Apparently so. If you split women up into those who experience PMS and those who don't, it's only those with PMS who suffer the rise in bad breath compounds as their period arrives, but the salivary flow was not statistically different. So the result suggests that a stressful situation can be a predisposing factor for bad breath that may have nothing to do with dry mouth or salivary flow. So what's going on? It's the effects of the stress hormones themselves on the production of bad breath compounds. They dripped some stress hormones on bad breath bacteria, hormones like adrenaline and cortisol, and they started churning out more hydrogen sulfide. What can we do about it if we can't treat the cause and reduce the stress? I have videos on dietary changes that can help, as well as tongue cleaning methods, and I have videos in the works on the effects of gum chewing and the best mouthwash to use that doesn't kill the good bacteria in your mouth. Stay tuned.