Understanding the risk profile of daily sparkling water

I drink sparkling water. On average, I go through 2-3 12 ounce cans per day. When I get bored or want to taste something, instead of eating snacks and junk food, I transitioned to drinking sparkling water. I like the bubbles and fruity taste; it’s help me avoid eating ultraprocessed junk and consuming mindless calories.

What are the potential risks of drinking sparkling water?

Tap water in the U.S. has fluoride in it which helps prevent tooth decay. Sparkling water has no fluoride. Assuming tap water makes up a good portion of your daily intake, you will get enough fluoride. (I drink about 65% tap, 35% sparkling).

Sparkling water has a lower pH than tap water. Carbon dioxide gas turns to carbonic acid when it interacts with saliva and water, lowering the pH of your mouth. Lower pH environments increase the probability of cavity formation. Of note, in low pH environments, fluoride does not prevent erosion (Larsen 2001). Relative beverage erosivity zones based on previous studies of apatite solubility in acid indicate that pH < 3 is extremely erosive, pH 3-4 is erosive, and pH above 4 is minimally erosive (Reddy et al 2016). pH’s of some sparkling water brands: Perrier mineral carbonated water ~5.5, La Croix ~4.8, Bubly ~4 (commerical testing). The “natural ingredients” cited on the bottle label often contain pH lowering compounds like citric acid. In comparison, Pepsi and Coca-Cola have pH’s around 2.4. Carbonated water is much better than soda; there exists a hierarchy of carbonated water brands. Perrier is the best option, followed by La Croix. Brittany Seymour, an associate professor at the Harvard School of Dental Medicine, says encourage people to think of sparkling water as a once-a-day treat rather than your main source of water and “if you want to have two or three sparkling waters a day, perhaps pair them with a meal” (NYT 2021).

Further comments from Seymour taken from the above NYT piece:

If you prefer drinking it alone, without food — Dr. Seymour usually drinks unsweetened seltzer while cooking dinner — use a straw to help the water bypass your teeth. In general, try not to sip it for more than an hour. Drinking carbonated water over a long time period prolongs the amount of time that your teeth are exposed to acidity. If you love fizzy water and like to drink it multiple times a day, without meals, consider brushing your teeth with a fluoride toothpaste afterward to stave off tooth decay. Why? The acidity of the carbonated water softens the enamel of your teeth. Taking a break gives your enamel a chance to re-mineralize and return to its normal hardened state, which is the ideal surface for brushing because it can better tolerate abrasives.

Carbonated water has, well, carbon dioxide gas. Depending on the person, it can contribute to bloating and gas in the form of flatulence and burps. If these things happen to you and it bothers you, consider decreasing your sparkling water intake. Otherwise, it’s fine.

Tap water is free. Sparkling water is not. At Costco, a 24 count box of 12 fl oz La Croix costs ~14 USD and 16.9 fl oz Perrier costs ~25 USD (as of June 2023). Assume a steady 2 standard 12 fl oz drinks consumed per day. How much does this cost per year? If you drink Perrier, it means spending 539 dollars per year. If you drink La Croix, it means spending 419 per year.

In short, drink Perrier if possible. Otherwise, La Croix. One a day is perfectly fine. Two is ok but anything more should be paired with food and maybe a fluoride toothpaste at night like Sensodyne.