LINDA WERTHEIMER, host:
This is MORNING EDITION from NPR News. I'm Linda Wertheimer.
STEVE INSKEEP, host:
And I'm Steve Inskeep. Today in Your Health, we'll hear about protecting yourself against cavities and against the flu. Treating water with fluoride is a time-tested way to help prevent or reduce cavities. But there may be another way, sugar - chewing gum or eating foods sweetened with a natural bacteria fighting sugar called xylitol. NPR's Allison Aubrey reports that the trick is knowing how much you have to consume.
ALLISON AUBREY: If you happen to check out the packaging of sugarless gum, as I am here in the supermarket checkout lane, you notice all kinds of health claims. Here I've got some Orbit. And on the back it says, helps fight cavities by strengthening teeth. Down below here, there's Trident. On the back it says, chewing Trident, which contains xylitol, helps fight cavities. So do all these health claims really hold up?
Dr. FRANCISCO RAMOS-GOMEZ (Pediatric dentist): You know, it depends on how much of the active agent is in that product, and how much you chew per day.
AUBREY: Francisco Ramos-Gomez is a pediatric dentist and a professor of dentistry at U.C.L.A. He says the popularity of sugar-free gums is an improvement. Simply because when you remove sucrose — or table sugar - the agent that helps rot teeth, there's a benefit. Since gum makers have now gone one step further - adding a natural sweetener called xylitol - there's potentially even more of a benefit. Xylitol can help kill off or starve the bacteria living on our teeth.
Dr. PETER MILGROM (Dentist): Xylitol is an anti-microbial — so it's acting against the bacteria themselves. So it helps prevent tooth decay.
AUBREY: Peter Milgrom is a researcher and dentist at the University of Washington, Seattle. He and his colleagues have studied how much xylitol is needed to actually knock out bacteria and prevent cavities. And he has two pieces of advice. First, glance at the ingredient list on the gum you're buying. If xylitol is the first ingredient, then there's probably enough of it to be effective. And second, chew a lot of it.
Dr. MILGROM: You need about six grams. So the typical piece of chewing gum that's sold in the United States that has xylitol in it, has around a gram. So you have to chew, you know, say at least two pieces, three times a day, to have any effect.
AUBREY: This may sound like an inordinate amount of chewing, but in Finland, school children have gotten used to it. Twenty-three year old Samuel Lindholm(ph), who's now living in the U.S., says when he was growing up, his parents, dentists and even teachers encouraged kids to chew xylitol gum after every meal.
Mr. SAMUEL LINDHOLM: It's healthy for your teeths. When you are young, it's really good to when you're teeths are still growing up and everything. So that was the reason.
AUBREY: Lindholm says they didn't blow bubbles, smack it around in their mouths, or make any sticky messes - at least, not that he can recall. But there's been a lot of tolerance for gum in Finnish schools ever since researchers documented the preventive effect back in the 1970s.
Now, for kids who are too young to chew or don't have access to good preventive care, Peter Milgrom has just shown in a study of a group of toddlers in the Marshall Islands that a xylitol syrup is effective.
Dr. MILGROM: This was a strawberry-flavored syrup that the kids ate without any trouble. And the mother just broke off the end of the little, squishy, plastic tube that we put it in, and squirted it on the child's teeth.
AUBREY: The syrup reduced the development of cavities by 50 to 70 percent, depending on how much kids received.
Now, dentists say it's important to remember that xylitol is not a magic bullet in fighting tooth decay. Burt Edelstein of Columbia University says people should stick with the basics of good oral hygiene.
Mr. BURT EDELSTEIN (College of Dental Medicine, Columbia University): Control of the diet, the regular use of fluoride toothpastes, good, ongoing supervision by a dentist...
AUBREY: And, of course, daily brushing. As for the claims that sugarless gums, which don't contain xylitol, may help strengthen teeth, too, Edelstein says there's indirect evidence that this is true. The gum can stimulate saliva flow, which helps fight plaque.
Allison Aubrey, NPR News.