Why do we get 'morning breath'?

THAT'S THE WHY:It's morning time, you are slowly surfacing from slumber, rolling over to check what time it is before stretching your limbs and peeling back the duvet.

Then it hits you: morning breath, that not-so-fresh feeling in the mouth department that often disappears if you brush your teeth or have something to eat or drink.

Why is it that even if you brush your teeth at night and don’t eat afterwards, your breath can be stinky a few hours later?

It’s because bacteria can still get to work on any remnants of food that might still be hanging around, as well as our own cells that are naturally sloughed off, and their actions produce smelly volatile sulphur-laden compounds.

It doesn’t help either that when we sleep we produce less saliva, which normally helps to put the brakes on this odour-creating activity.

A recent study in the Netherlands looked at levels of three of the stinky compounds (hydrogen sulphide, methyl mercaptan and dimethyl sulphide) immediately after waking. They asked 50 healthy volunteers to collect breath samples on waking, then they used gas chromatography to analyse the volatile sulphur compounds they contained.

The study found methyl mercaptan in almost 90 per cent of the samples. Hydrogen sulphide and dimethyl sulphide were in about two-thirds, but interestingly tended to crop up more in the female volunteers.

“We can conclude that a large number of the volunteers suffer from morning halitosis,” write the researchers in the Archives of Oral Biology. “Our first study demonstrates that this is only a transient phenomenon that in most volunteers disappears after breakfast, even without direct dental hygiene.”