Is Seltzer Bad for Your Bones?
It's having a total moment—but is it actually ok to drink?
Whether you're partial to La Croix, Bubly, Spindrift, or a bevy of other brands, flavored seltzer is everywhere. (Especially spiked seltzer, lest we forget the White Claw shortage of 2019.) From 2012 to 2018, sales of carbonated waters increased 88 percent, according to market research company Euromonitor as reported by Quartz.
Most people are swapping soda for seltzer in an effort to quench their thirst for bubbles without the negative side effects for their health. While seltzer is missing some of the obviously unhealthy qualities of soda (like sky-high sugar content)—is it really void of all the risks?
More specifically, if some soda has been linked to poor bone health, does that mean seltzer could be bad for your bones, too? We asked dietitians to set the record straight.
What is seltzer exactly?
"Seltzer is carbonated water, which is water infused with carbon dioxide and sometimes flavor (generally natural flavor)," says Melissa Majumdar, R.D.N., registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics.
Seltzer is naturally sugar-free and calorie-free, making it a fab option for those trying to kick a soda habit. And, if you've heard the rumors that seltzer dehydrates you, that's wrong:
"Since unflavored seltzer water is simply regular water with added carbon dioxide, it's just as hydrating as plain water," confirms Cordialis Msora Kasago, R.D.N., registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics. "However, due to its effervescent nature, some people tend to fill up quickly when they drink it and therefore drink less water than when they drink simple plain water." So if bubbly is your only source of water, be sure to drink up.
Is seltzer bad for your bone health?
For starters, let's talk about why it could be. Soda contains phosphorus, and while research isn't conclusive yet, studies indicate that it might impact your bone density.
"When phosphorus levels are elevated and calcium levels are low, the body produces a hormone called PTH (parathyroid hormone) to signal the body to send out less calcium through the kidneys, absorb more calcium in the intestines, and borrow calcium from bone," says Majumdar. "The amount of phosphorus in carbonated drinks like soda shouldn't impact this feedback cycle, but nonetheless soda has been found to decrease bone mass."
Good news: If you drink tons of sparkling water, your bones shouldn't have anything to worry about.
"Unlike other carbonated drinks like soda, seltzer doesn't contain caffeine or phosphorus, which both have had mixed results [in research] when it comes to the impact on bone density," says Majumdar.
One small study published in the British Journal of Nutrition compared women who drank a quart of carbonated water with women who drank a quart of non-carbonated mineral water for eight weeks, and found that there was no difference in their bone health based on blood and urine tests after the 8-week period.
(In case you're now worried about your coffee habit, too: Research shows that caffeine may negatively impact calcium absorption, but it's a small enough amount that it could be "fully offset by as little as 1–2 tablespoons of milk," according to a 2002 study published in Food and Chemical Toxicology.)
Are there any other risks to drinking seltzer?
If you're a selzter-holic, you don't have to worry about phosphorus messing with your bones—but, unfortunately, your mouth bones (a.k.a. teeth) could be at risk.
"Additives in seltzers like citric acid can impact tooth enamel, the coating on the outside of a tooth that keeps it strong," says Majumdar. Not to mention, the carbonation itself can play a part: Carbon dioxide reacts with water to create carbolic acid, which may wear away at tooth enamel, according to registered dietitian Carolyn Brown, M.S., R.D., as we reported in Is Your LaCroix Habit Actually Healthy?
The impact on your teeth may actually depend on the brand of seltzer itself. Enamel starts to erode as a drink's pH level (a measure of how acidic something is) drops below 5.5. A pH analysis of common drink brands in the U.S. by the American Dental Association (ADA) found that, for example, Perrier has a pH level of 5.25, Canada Dry Club Soda has a pH of 5.24, and San Pellegrino Sparkling Water has a pH of 4.96, which are all labeled as "minimally erosive." (Meanwhile, regular water has a pH between 6.5 and 8.5.)
That said, the analysis shows that juice, soda, sports drinks, tea, and flat, flavored waters have even lower pH levels: Classic Coca-Cola has a pH of 2.37, Powerade flavors dip down to 2.73, Vitamin Water hovers around 3, and Arizona iced tea hits 2.85, just to name a few. The ADA didn't test any flavored sparkling waters, but it's possible that those additional ingredients could have an impact on pH levels.
Comparatively speaking, that means seltzer or sparkling water is likely a better option than any of these other drinks, but not as good as regular water, if you're concerned about your enamel.
So are we good to drink seltzer?
"There is no true limit to drinking seltzer (from a bone-health perspective)," says Majumdar. If you have issues with your tooth enamel, you might want to consult with your dentist or doc, but you likely don't have much to worry about—except maybe a seltzer belly.
"The amount of seltzer you should drink really depends on how much your stomach can tolerate," says Msora Kasago. "People who experience gas, bloating, and other signs of stomach discomfort after seltzer water should limit the amount they drink." (Other than that, there aren't any digestive repercussions to drinking seltzer, and it might actually be beneficial for digestion.)