HALITOSIS
It's a curse in social circles and a killer when it comes to romance. While all of us experience it at different times in our lives, some people are stricken with a chronic, and particularly smelly, form of the condition. We're talking bad breath.

We all know onion and garlic-laden dishes result in oral odour but few realise what else causes the condition or, more importantly, how to get rid of it.

"Bad breath is the result of bacteria living in your mouth," says Sydney-based dentist Dr Geoffrey Speiser. "Actually, it's the waste products of bacteria that live in your mouth."

According to Speiser, there are three main causes of bad breath - lifestyle, hygiene and illness. "There's good and bad bacteria in our mouths so the kinds of food that promote the wrong types of bacteria involve some kinds of proteins," he says. "A diet high in dairy - cheese, ice cream, milk and yoghurt - can cause bad breath and this is because most of those foods break down to sulphur compounds."

Sulphur has the kind of smell, Speiser says, that reminds people of rotten eggs. Apart from dairy proteins, acid is another cause of bad breath. "The higher the acid level in your mouth, the higher the number of bad bacteria," Speiser says. "Acids come from soft drinks, specifically diet drinks, sports drinks and coffee. "Sugars are another source and you find those mostly in reconstituted juices, soft drinks and alcohol."

While Speiser's list of no-nos rules out any kind of beverage other than water, he says it's all about moderation. How bad your breath smells, as well as how long it lingers, depends on overall diet, health and lifestyle.

Speiser works closely with New Zealand microbiologist Professor John Tagg who, in 2000, discovered a world-first probiotic treatment for halitosis.

Tagg's discovery prompted Speiser, in 2004, to open The Australian Breath Clinic which is now the exclusive distributor of Tagg's treatment, K12, which is a powder that gets reconstituted in water and swished around the mouth. K12 gets rid of the bad bacteria while leaving behind the good ones.

So what other foods cause bad breath? It's true about onions and garlic because they already contain sulphur compounds, as do brussels sprouts and cabbage. But fruits high in sugar, like grapes and dried apricots, also cause bad breath, as can highly processed breads. Speiser recommends people stick to lettuce, celery, carrots, tomatoes and old-fashioned goodies such as apples and oranges.

"Dieting can also cause bad breath," he says. "When we break down body fat, we release ketones which can cause bad breath but it won't stay chronic if there are no other factors involved."

By other factors, Speiser includes hygiene. People who don't clean their teeth, scrape their tongue and floss every 24 hours are more likely to have bad breath. Bacteria that causes smell don't bond to the tongue or tooth directly so if you're cleaning the coating off every day properly, the bad bacteria can't be supported," he says.

Illnesses and medications can also be halitosis-causing, in particular nasal problems, dry mouth and long-term use of antibiotics. "Things that trigger a dry mouth are depression, thyroid problems, uncontrolled diabetes and some medications," Speiser says.

More than 50 per cent of middle-aged people have a breath issue, Speiser says. For long-term fresh breath, he suggests a healthy diet with all things in moderation, good oral hygiene daily and perhaps a rinse with K12, if the bad bacteria get particularly nasty.

In the short term, gum and sugar-free sweets that contain artificial sweeteners such as xylitol can help as well as parsley, sage and other herbs.