Plain carbonated water is, for most people, a perfectly healthy drink. It hydrates just as well as still water, doesn’t damage your teeth in any meaningful way, and contains zero calories (assuming no added sugar). The fizz itself does have some real effects on your body, both helpful and not, but none of them are serious enough to put sparkling water in the “bad for you” category.
Carbonated Water Hydrates Just Like Still Water
The most common concern people have about sparkling water is whether it actually counts toward their daily water intake. It does. In a study where participants drank a liter of either still water, sparkling water, or other beverages, researchers measured urine output four hours later and found no difference in hydration status between the carbonated and flat water groups. If you prefer the taste of fizzy water and it helps you drink more throughout the day, that’s a net positive.
What Carbonation Does to Your Teeth
Dissolving carbon dioxide in water creates a mild acid, which raises a reasonable question about enamel erosion. But when researchers tested sparkling water against regular water on extracted human teeth, the two had essentially the same effect on enamel. Plain sparkling water is, as the American Dental Association’s consumer site puts it, “all just water to your teeth.”
The important distinction is between plain sparkling water and flavored or sweetened versions. Any carbonated drink with added sugar is a sugar-sweetened beverage, and it carries the same cavity risk as soda. If the ingredient list includes sugar or high-fructose corn syrup, you’re no longer drinking sparkling water in any meaningful nutritional sense.
Digestive Effects: Helpful and Not
Carbonation has a genuine benefit for digestion in at least one area: constipation. A clinical study on elderly patients found that drinking carbonated water significantly increased the frequency of bowel movements and reduced constipation symptoms. If you deal with sluggish digestion, sparkling water may offer mild relief.
Carbonation also appears to help with swallowing. The dissolved CO2 stimulates nerve endings in the mouth and throat, activating sensory pathways that sharpen the swallowing reflex. A meta-analysis found that carbonated liquids tend to decrease aspiration (food or liquid entering the airway) compared with flat liquids. This is particularly relevant for older adults or anyone with swallowing difficulties.
On the other hand, the gas has to go somewhere. Carbon dioxide can distend the stomach and intestines, which may cause bloating, burping, or discomfort. For people with irritable bowel syndrome, at least one clinical guideline recommends reducing fizzy drink intake to manage symptoms. The evidence linking carbonation to IBS flare-ups is mostly anecdotal, but if you already deal with bloating, it’s worth paying attention to whether sparkling water makes it worse.
The Bone Density Question
There’s a persistent belief that carbonated drinks weaken your bones. This one has a grain of truth, but the culprit isn’t carbonation itself. A major study from the Framingham Osteoporosis Study found that cola was associated with significantly lower bone mineral density in women, with daily cola drinkers showing 3.7% lower density at the femoral neck (part of the hip) compared to women who rarely drank cola. But noncola carbonated beverages showed no such association.
The problem with cola appears to be its phosphoric acid and caffeine, not its bubbles. When researchers specifically tested the effect of different carbonated drinks on calcium loss through urine, only beverages containing caffeine caused increased calcium excretion. Drinks with phosphoric acid but no caffeine did not. Plain sparkling water contains neither phosphoric acid nor caffeine, so it poses no known risk to your bones.
One Potential Downside: Appetite
This is the one finding that gives some pause. A study reported by UCLA Health found that both rats and humans who drank carbonated water had significantly higher levels of ghrelin, the hormone that triggers hunger. In the human portion of the study, 20 male participants who drank carbonated water (sweetened or unsweetened) had triple the blood levels of ghrelin compared to those who drank flat water or degassed sparkling water. The researchers concluded that the carbon dioxide itself drove the increase in ghrelin production.
Higher ghrelin doesn’t automatically mean weight gain, but it does mean you may feel hungrier after drinking sparkling water than you would after the same amount of still water. If you’re watching your calorie intake, this is worth knowing. It’s a single study with a small human sample, so it’s not a definitive verdict, but the mechanism (CO2 directly affecting ghrelin) is plausible.
Not All Fizzy Water Is the Same
The health profile of your carbonated drink depends entirely on what’s in it beyond the bubbles. Here’s how the main types compare in a 12-ounce serving:
- Seltzer is just water plus CO2. Zero calories, zero sugar, no added minerals.
- Club soda adds minerals like sodium bicarbonate and potassium sulfate for taste. Still zero calories, but contributes about 3% of your daily sodium.
- Sparkling mineral water comes from a natural source and contains minerals like calcium (up to 9% of your daily value) and magnesium (up to 9%). Zero calories.
- Tonic water is the outlier. It contains 124 calories and 32 grams of sugar per 12-ounce serving, comparable to a can of soda. The quinine that gives it its bitter flavor is present in small amounts and is mostly masked by all that sugar.
If you’re drinking sparkling water for health reasons, seltzer, club soda, and mineral water are all fine choices. Tonic water is a sweetened beverage and should be treated as one. The mineral content in club soda and sparkling water sounds appealing but is too low to make a real nutritional difference on its own.