N.B. This post may be considered, um, politically incorrect. Let's just consider it in a clinical context.
I am jewish, well, my mitochondria is. And if I'm right, my oral microbiome, rather, my breath, is as well. I call it "Jew Breath". It resembles mothballs(note: this is not my breath all the time, only occasionally!). I've noticed it a lot at Temple and had it independently confirmed by an old jewish roommate:
"You know what I'm talking about" I said to A. "Jew Breath is real!". A put his face in his hands, smiled, and nodded slowly, admitting the painful truth. I could smell it on him too.
As an SGU'er, with my school's majority Indian population, I also noticed among some a certain "Indian Breath" (or more offensively: Desi Breath). I can't quite put into words what it smells like, but I prefer it to Jew breath. Anyways, a fellow (caucasian/goyim) med student who is dating an Indian women actually had that breath... which means either the smell is not associated with the subcontinent OR she transferred some of her oral flora to him through excessive make out sessions (how long and how many remains a subject for further study).
There is some clinical relevance to this, however. Analyzing the myriad microbiomes of the gastrointestinal tract is a hot research topic,implicated in everything from Chron's disease, type 1 diabetes, failure of anastomeses in surgery (from a grand rounds lecture pre-pub) to development of pancreatic cancer. And it turns out, some research has found a difference in the oral microbiome of different ethnicities.
So maybe there is something to Jew Breath after all...