What is xylitol and should we all be eating it? Hilly Janes investigates the sweetener that's on everybody's lips

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What’s all the fuss about?

Xylitol is a plant-derived sweetener that has about 40 per cent of the calories of sugar, but tastes just like it. Unlike aspartame and other chemical sweeteners, it’s completely natural. But its role in preventing tooth decay is what's on everyone’s lips.

Xylitol is claimed to have antibacterial properties that can help fight tooth decay, the build up of plaque and gum disease - which can imperil your pearly smile as much as tooth rot. Decay-causing bacteria feed off sugar, but not xylitol, so that also defends us against the dentist’s drill - hence a host of gums and lozenges containing the stuff. Recent media coverage has even boosted profits; Peppersmith , a UK brand, credits one recent article with doubling its sales.

It’s also used to sweeten products aimed at diabetics, who need to control their sugar intake.You can find bags of granulated xylitol in big supermarkets - albeit at ten times the price of ordinary sugar. (If you are diabetic, check with your doctor before switching).

The sweets you can eat between meals?

Companies like Peppersmith, set up in 2009 by some young bloods from the Innocent smoothie company using xylitol derived from beech trees, claim that it’s a good idea to suck or chew their goodies after meals.  

“It’s good for teeth and means our gum is proven to help reduce plaque and the risk of tooth decay,” proclaims the charmingly retro packet of their spearmint flavour that I am chewing for research purposes. Mints in the UK contain up to 83 per cent sugar, says Dan Shrimpton of Peppersmith, and he points out the irony of sucking them to freshen your breath, while possibly wrecking your teeth.

Spry , a US brand I tried, makes similar claims; I wouldn’t have known the difference between these and normal gum, except that the taste seemed to fade in about a minute.

What’s the evidence?

A lot of studies have supported the claims for xylitol, which has been around for years and is widely used as a sugar substitute in other parts of the world, like Scandinavia (plenty of trees to spare there...). But in January 2013 a large trial reported in the Journal of the American Dental Association said that sucking lozenges containing the magic ingredient made little difference to adults at risk of close encounters with the dentist’s chair.

Bin the brush and forget the floss?

At your peril. Brushing carefully twice a day for two minutes and daily flossing, both with gentle circular movements, are the basic requirement. Xylitol can’t remove bits of food stuck between your teeth that bacteria feed off, and there’s scant evidence that it can help prevent gum disease. Some experts argue that in any case, chewing and sucking anything creates saliva, a natural defence mechanism against bacteria.

Topping up with xylitol gums and lozenges won’t do you any harm - though in large quantities they can have a laxative effect - and xylitol can be helpful for untamed toddlers who can’t or won’t brush and are too little for flossing. On the other hand if you introduce the idea to small children that sucking sweeties is good for you, you’ll damage their mental, let alone dental, health.

What’s the small print?

The suggested daily intake is about 6-10g, in products containing 100 per cent xylitol and not sugar or other sweeteners. If you choose Peppersmith gum, that means about five to six pieces per day, which apart from all the chewing, at 15p each works out at about £1 or £365 a year. That’s equivalent to six visits to a private dental hygienist for a proper cleaning job, or a top of the range electric toothbrush each for a family of four.

Having chewed it over...

Given you’d need to develop quite a pricey habit to make any difference to your dental health, it’s probably best to think of xylitol products as something to switch to if you are already a sucker for sweets. As Professor James Bader of the University of North Carolina and lead author of the study said: "Use it, but don't rely on it." Just don’t let the dog near them - xylitol messes with their blood sugar and is very dangerous.