The carbonation per se isn’t bad. But fizzy soft drinks can give you gas and heartburn, the sugar in non-diet drinks adds useless calories and can give you cavities. And you’d be better off drinking a glass or two of bone-enhancing, low-fat milk, instead.

Scientists have wondered whether the phosphoric acid in many soft drinks might damage bones, but they’ve looked and found “there really isn’t any evidence that carbonated beverages affect bone health,” said Dr. Michael Holick, professor of medicine, physiology and biophysics at Boston University Medical Center.

For that reason, said Dr. Suzanne Jan de Beur, director of endocrinology at the Johns Hopkins Bayview Medical Center, “I don’t tell patients not to drink soft drinks.”

But even though soft drinks don’t directly harm bone, they can have an indirect effect if you substitute them for calcium-rich milk, said Dr. Felicia Cosman, clinical director of the National Osteoporosis Foundation. If you get enough calcium from milk or other foods, she said, soft drinks probably wouldn’t have much impact on bones.

As for teeth, “tooth enamel is harder and more dense than bone,” so the damage to teeth is probably slight, said Dr. Thomas Van Dyke, a professor of periodontology and oral biology at the Boston

University School of Dental Medicine. A person would have to drink an extreme amount of carbonated beverages for the carbonic acid to leach calcium out of teeth, he said. The sugar in soft drinks, though, is horrible for teeth because bacteria that eat the sugar produce an acid that creates cavities.

If you simply must drink sugary soft drinks, you can at least drink them through a straw. A report in the May/June issue of General Dentistry noted that drinking through a straw positioned toward the back of the mouth can help reduce cavities.