In Greek mythology, the many-headed beast Hydra had such severe halitosis that the stench of its breath was deadly to anyone who smelled it. Thankfully, our morning breath might not be that pungent – although eating onions or garlic can put some people in competition with the Hydra.

Halitosis has many causes (aside from poor oral hygiene) and can indicate problems with the gut, the sinuses and even the bloodstream. In fact, breath samples can even be tested to make formal diagnoses of health conditions.

One condition that can affect the smell of breath is diabetes mellitus. This is a metabolic disorder where sugar (glucose) is unable to access the body’s cells where it is needed to provide energy, and so rises in the bloodstream.

In some instances, such as insufficient insulin dosing, or infection, the body’s response is to break down fats into compounds called ketones to act as a rapid form of fuel. This serious condition is called diabetic ketoacidosis.

Ketones have a distinctive scent. Acetone, which is also an ingredient in some nail varnish removers, is one of these ketones and has the smell of pear drops. When ketones build up in the bloodstream they easily diffuse into the breath, giving it a fruity odour.

It’s not just diabetes that can........

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