Drinks with a lot of sugar will rot your teeth, right? That's the conventional wisdom.
But what about the acid? It's not something we think much about, but dentists say it's high time we start, especially when it comes to the river of energy drinks we — and young people in particular — are consuming.
In a study published in the May/June issue of General Dentistry, researchers have looked for the first time at the effects of energy drinks on teeth. It turns out there's often a lot of citric acid in the drinks.
Why? It's a preservative that enhances flavor and shelf life. But it also happens to be very good at stripping enamel from teeth.
Dentists are especially worried about teens — 30 to 50 percent of whom are estimated to be gulping down energy drinks — losing enamel because once it's gone teeth are more prone to cavities, and more likely to decay.
"We are well aware of the damage that sugar does in the mouth and in the whole body — the role it can play in obesity, diabetes, etc," says Poonam Jain, an associate professor in the School of Dental Medicine at Southern Illinois University, Edwardsville, and the lead author of the study. "But the average consumer is not very well aware that acid does all kinds of damage, too."
To measure just how energy and sports drinks affect teeth, the researchers looked at the fluoride levels, pH, and something called "titratable acidity" of 13 sports drinks and nine energy drinks, including Gatorade and Red Bull. That last data point, by the way, is all about how long it takes for saliva to neutralize acid in the mouth.
The researchers then measured how much enamel the drinks took off teeth, dousing sliced-up molars in a petri dish with the beverages for 15 minutes, followed by artificial saliva for two hours. The was repeated four times a day for five days.
The researchers found that teeth lost enamel with exposure to both kinds of drinks, but energy drinks took off a lot more enamel than sports drinks.
The precise amount of citric acid in a drink isn't something beverage companies have to declare on the label. And the American Beverage Association says drinks can't be blamed for damage to teeth.
"It is irresponsible to blame foods, beverages or any other single factor for enamel loss and tooth decay (dental caries or cavities)," the ABA said in a statement responding to Jain's paper. "Science tells us that individual susceptibility to both dental cavities and tooth erosion varies depending on a person's dental hygiene behavior, lifestyle, total diet and genetic make-up."
And, it should be said, previous research in the same journal showed that acids in citrus fruit juices (particularly lemon juice) can also erode the enamel on teeth.
Jain, the dental researcher, is concerned about health effects beyond cavities . She says consuming a lot of citric acid can lead to loss of bone mass and kidney stones. "This has become a big concern because people are drinking more of these drinks and less milk," she says.
This dust-up over acid isn't the first time, of course, that energy drinks have come under fire from health experts.
Last year, as we reported, the American Academy of Pediatrics said children should never drink caffeinated energy drinks out of concern about what high doses of caffeine can do to a young growing body that's not fully mature.