The sports drinks and energy drinks that up to 62 percent of teens drink regularly deliver more than calories and caffeine. A new study shows that high acid levels can permanently damage the glossy enamel of their teeth.

"Young adults consume these drinks assuming that they will improve their sports performance and energy levels and that they are 'better' for them than soda," says Poonam Jain, B.D.S., M.S., M.P.H., lead author of the study and director of The Community and Preventive Dentistry Program at Southern Illinois University. "Most of these patients are shocked to learn that these drinks are essentially bathing their teeth with acid."

Jain and her team swished samples of human tooth enamel in 13 different drinks for 15 minutes four times a day, then stored the enamel chips in artificial saliva the rest of the time. After just five days, the enamel showed signs of wear.

Worn enamel isn't just a cosmetic problem. When this hard stuff gets scuffed-up, the inner structure of their teeth loses protection. Eating hot, cold or sweet foods or drinks could cause pain, because microscopic tubes leading to the nerves in a tooth are exposed. Rough edges, yellow surfaces, dents and more cavities are also signs of worn enamel.

Energy drinks caused twice as much damage as sports drinks. But other beverages and foods can also etch the surface of their teeth (and yours), including most soda, citrus fruit and juices, Jain found in a previous study.

You can protect your teens teeth by:

• Suggesting they sip sodas and sports drinks through a straw – and skip or limit energy drinks.

• Recommending a lower-acid drink, like root beer, milk, iced tea or water.

• Suggesting they chew sugar-free gum afterward.

• Rinsing with water after having a high-acid drink or food