Is Seltzer Water Just As Hydrating As Regular Water?

Everything you need to know about your favorite fizzy drink.

Photo by: iStock


If you take a look at the cans on your co-workers’ desks, you may notice there are less sodas and more seltzers. A 2017 NPR story reported that Americans are chugging 170 million gallons of seltzer a year, and sales were up 42% in a five-year span. While seltzer is not a new drink (Perrier launched in the United States in 1971), it’s been gaining popularity in recent years as an alternative to diet soda and other calorie-laden drinks. And the flavors are enticing — everything from tropical coconut to crisp grapefruit and juicy pear.

But at its most basic, plain old seltzer is just your standard H2O with CO2.

“Seltzer water is plain water that has carbon dioxide added under pressure to create that bubbly effect that many people love,” says Cordialis Msora-Kasago, MA. RDN, and spokesperson for the Academy of Nutrition and Dietetics.

And while it’s got more going on texture- and flavor-wise than plain old water, it’s equally as hydrating.

“Science shows seltzer water is just as hydrating as regular tap water,” says Jessica Crandall Snyder, RDN, registered dietitian nutritionist at Vital RD in Denver. “It doesn’t dehydrate you. From a mouth-feel standpoint, it may not seem as hydrating. But from a nutrition standpoint, they are equal.”

So if you’re obsessed with seltzer, there’s good news: it counts towards your daily water intake totals.

The Institute of Medicine’s dietary recommendations for water intake are:

Men: At least 101 ounces of water per day (slightly under 13 cups)

Women: At least 74 ounces (a little over 9 cups)

However, there really is no clear-cut designation for how much water each person should drink because many factors play into it.

“When looking at hydration, you have to consider how active a person is, the climate they live in, how much they exercise,” says Crandall Snyder. “But I tell my clients a really good goal to shoot for is ounces of half your body weight.” (So for example, if you weigh 150 pounds, you should aim for at least 75 ounces of water per day.)

Of course, seltzer can have some downsides.

“People who experience gas, bloating and other signs of stomach discomfort after a seltzer water should limit the amount they drink,” says Msora-Kasago.

But plain, carbonated water has not been shown to have any major adverse effects on health.

A study published in the American Journal of Clinical Nutrition found that carbonated waters do not impact density or bone health.

Besides a distended belly, the only other downside to seltzer is that it is slightly acidic compared to tap water, thanks to the CO2 that turns into carbonic acid. According to the American Dental Association, dental erosion happens in an acidic environment “in the pH range of 2.0 to 4.0, although surface enamel starts to demineralize as the pH drops to less than 5.5." Perrier has a pH level of 5.25, while water has a pH between 6.5 and 8.5.

However, in one study that compared the erosion of sparkling water to tap water, it found that “sparkling mineral waters showed slightly greater dissolution than still waters, but levels remained low and were of the order of one hundred times less than the comparator soft drinks.”

So drinking seltzer is still no where near soda. However, if you’re drinking carbonated waters with additives, those could have negative impacts.

“Sweetened and flavored carbonated water may contain ingredients such as acids, sugar and sodium which may negatively affect a person's health,” says Msora-Kasago. “For example, beverages with sweeteners may contain calories and when consumed in large amounts contribute towards weigh gain. Similarly, when consumed in large amounts, beverages that contain acids may erode tooth enamel increasing the risk of tooth decay.”

But the bottom line on plain seltzer: It’s just as hydrating as water, and if you’re sticking to seltzer without added sugar, acid or sodium, you shouldn’t expect any negative health issues (besides bloating and gas).

“The good news for seltzer lovers is that each glass counts towards your daily fluid intake, so go ahead and include it on a regular basis,” says Msora-Kasago. “The amount of seltzer that one takes a day is really dependent upon how much one can tolerate.”

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