The lesson: We don’t hold seltzer in our mouths for half an hour, so even if you drink five cans of seltzer in a day, your teeth should be just fine. (Especially if you've switched to seltzer in an effort to reduce your soft drink consumption.)As for any concerns about your bones, the research is pretty clear that, if anything, it’s colas or other types of soda that may affect bone density. Not seltzer. One study compared the effects of different carbonated beverages on bone, using data from 2,500 middle-aged men and women. The study found that colas, but not other carbonated beverages, are associated with low bone density in women (but not in men).So if your favorite beverage is seltzer, go ahead and sip it throughout the day. It's no big secret that staying hydrated is important — water plays a role in everything from your body's temperature regulation to the way your joints work, and seltzer totally counts. To avoid dehydration, follow your thirst cues just as you would your hunger cues (the "eight glasses a day" rule really isn't in favor anymore ). You may have heard the claim that by the time you’re thirsty you’re dehydrated, so you should drink before you feel thirst — but that’s also a myth. If you’re healthy and not elderly, and as long as you’re not exercising vigorously in a hot climate, following your thirst cues is enough to keep you from getting dehydrated. (Elderly folks have a diminished sense of thirst , and athletes in hot climates may lose more fluids than can be replaced by drinking according to thirst, so that’s why these groups may benefit from paying closer attention to their fluid intake.)One last thing to consider with your seltzer habit: If you’re drinking seltzer to try to suppress your appetite or avoid snacking, stop. Your body needs and asks for snacks between meals, and honoring that need — rather than suppressing it by filling up on bubbly water — is an important part of creating a healthy relationship with food. Otherwise, feel free to fill your fridge with the fizzy stuff — and to ignore any fear-mongering still-water purists.Christy Harrison is an NYC-based registered dietitian nutritionist specializing in intuitive eating, eating disorder recovery, and Health at Every Size. She writes about food and nutrition for various publications and hosts Food Psych , a podcast dedicated to improving your relationship with food.