British soul singer Joss Stone has been widely quoted in newspapers and online media as saying thatbad breathis her biggest turn-off in a man.

That's not surprising. In fact, it is a perfectly natural way to feel. And she isn't alone: An extensive survey carried out by the British Dental Association in London some years back found that bad breath was ratedthe #1 turn-off for everybody, no matter what their age or gender. It was even rated as beingworsethan stale body odor!

Stone, 23, said: "There is nothing worse than bad breath. I have kissed people with bad breath... and it made me feel sick." And, in all probability, that was not a figure of speech – it really did make her feel physically sick.

That's because ofdisgust, which is one of the 6 primary human emotions. Normally, we think of emotions as being a purely 'mental' thing but, according to researchers, disgust is quite different: it is often purely physical, involving a sequence of involuntary movements that originally evolved as a way to protect us from sources of disease or infection.

Because the nose is so close to (and, hence, well connected with) the brain, the sense of smell is the primary driver of disgust. The chemical compounds given off by things that can cause disease or infection often have a very distinctive smell, which the human brain recognizes instantly. When it does so, it switches to survival mode right away, and literally forces your body to isolate itself from the source of possible infection.

It does that by making yourecoil(which moves you away), scrunching up your nose (which constricts your nasal passages, and stops you breathing in any more noxious smells), and by making yougag(which stops you swallowing anything through your mouth). If you do breath in (or swallow) too much of those chemicals, you then feelnauseated, and may evenvomit(which ejects everything you have swallowed from your body).

As it happens, bad breath contains a number of specific chemical compounds that happen to be the SAME as those given off byrotting food, feces, and, believe it or not, dead bodies– all sources of possible infection, and all causes of (sometimes extreme) disgust in every single human being on the planet. If you have bad breath , THAT'S why people recoil, turn away, and step back when you are near them.

That's why it's so sickening. It doesn't matter if the people around you like, or even love you – their brain thinks you could literally kill them, and is trying to protect them by making them feel sick and disgusted by you.

And that's why Stone is right:There really is nothing worse than bad breath!