Ask the Doctors

Dear Doctor: We're finally winning the battle against sugary soft drinks in our home, but a family friend insists that the sparkling water our kids are drinking instead is bad for their bones and teeth. Is this really true?

Dear Reader: First, congratulations on weaning your family off of soft drinks. One out of every three Americans drinks at least one (and often more) sugar-packed soda or other sweetened beverage every day. This puts them at increased risk for serious health problems such as obesity, Type-2 diabetes and even heart disease.

Although in a perfect world we would all stick to plain water to get the hydration we need, the truth is that can get boring. It's no surprise, then, that sparkling water, with its fizzy bubbles and wide range of flavors, has become a go-to replacement for people who want to cut back on calorie-laden sodas.

Sparkling water, which typically has no calories, is made when carbon dioxide gas is dissolved in plain water, a process known as carbonation. This results not only in the bubbles we love, but also creates carbonic acid, which gives fizzy water a mildly tart flavor. (We'll get back to that in a minute.)

The concern voiced by your family friend, that drinking carbonated water weakens bones, quite possibly finds its roots in a study conducted in 2006. Known as the Framingham Osteoporosis Study, researchers tied the consumption of cola beverages to decreased density in the hip bones of older women.

But the operative word here turns out to be "cola." Women in the study who drank non-cola beverages did not exhibit increased bone loss. The researchers concluded that carbonation doesn't damage your bones.

As to the question of carbonation being bad for your teeth, we need to talk about the carbonic acid we mentioned earlier.

While it's true that the process of carbonation results in the creation of an acid, it's a very weak one. Plain bottled water has a neutral pH of 7. Carbonated water such as Perrier is only slightly more acidic, with a pH of 5.25. According to the American Dental Association (ADA), that's "minimally corrosive." Cranberry juice, by contrast, with a pH of 2.5, is considered by the ADA to be "extremely corrosive."

So the good news is that you and your family are on the right track with fizzy waters replacing sodas and other sweet drinks. Just be sure to always read the labels. If you see the words sucrose, glucose, fructose or corn syrup, you're holding a sugary drink.

And here's a bonus for weight watchers from a National Institutes of Health study: Young women who drank a glass of fizzy water reported feeling full and satiated.

Lastly, for those of you with kids who may have heard this urban legend -- eating the carbonated candy Pop Rocks and then drinking a soda will definitely not make your stomach explode!

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

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