Does sparkling water count as water? Hydration, teeth and bloating

Yes. Plain sparkling water counts as water, and as far as anyone can tell it hydrates you about as well as still water does. The bubbles are carbon dioxide dissolved in the water, and they don't change how your body takes in the water underneath them.

What is worth knowing sits around the edges: whether the fizz is hard on your teeth, why it sometimes leaves you bloated, and what changes when the can says "flavored" or "zero sugar".

Does sparkling water hydrate you as well as still water?

The research is not huge, but it points one way. A 2016 study, sometimes called the beverage hydration index study, compared how well about a dozen everyday drinks kept people hydrated over the following few hours. Sparkling water came out about the same as still water. It was a short study in healthy young men, so it is not the last word, but nothing in it or elsewhere suggests that the bubbles get in the way.

Health services treat it the same way in practice. The NHS counts water, lower fat milk and drinks without added sugar, tea and coffee included, toward your daily fluids, and plain sparkling water fits that easily. If you are not sure how much to aim for in a working day, how much water should you drink at work sets out what health bodies actually say.

There is one practical difference. Some people find they drink less sparkling water at a time, because the gas fills the stomach faster. That is about how much you drink, not how well it hydrates. A can sipped over half an hour still counts in full.

Seltzer, club soda, mineral water and tonic

Not everything with bubbles in it is the same drink, and the label tells you which one you have.

If you have been told to watch your salt, check the label on mineral water and club soda. Most are low in sodium, but some mineral waters are not.

Is sparkling water bad for your teeth?

When carbon dioxide dissolves in water, some of it forms a weak acid, carbonic acid. That is what gives sparkling water its slight bite. Acid is also what wears tooth enamel away over time, which dentists call erosion, so the question is a fair one.

The reassuring part is that plain sparkling water is only mildly acidic, far less so than soft drinks, fruit juice or sports drinks. The American Dental Association's advice for the public is that plain sparkling water is generally fine for your teeth, and it singles out citrus flavored versions as more acidic. Lab studies on enamel point the same way: plain fizzy water does very little, while flavors with added citric acid can do noticeably more.

If you drink a lot of it, a few habits keep the risk low:

• Drink it, don't nurse it. A can finished in one sitting, or with a meal, is easier on enamel than one sipped from 9 AM to noon. Saliva needs gaps between sips to neutralize acid.
• Make plain your everyday can. Keep the lemon and grapefruit flavors as the occasional one.
• Alternate with still water, or swish a mouthful of plain water after a flavored can.
• Don't brush straight afterward. Enamel is softer just after anything acidic, so dentists usually suggest waiting a while before you brush.
• Ask your dentist if your teeth are already sensitive or you have been told you have erosion. They can tell you whether your habit is a problem for your teeth in particular.

Does sparkling water make you bloated?

It can. The bubbles are gas, and some of that gas ends up in your stomach. Most of it comes back up as a burp, but some people feel full, tight or bloated after a can, especially if they drink it quickly, through a straw or with a big meal.

For most people that is a comfort issue, not a health one, and it is easy to manage:

• Pour it into a glass and let it settle for a minute before drinking.
• Sip rather than gulp.
• Choose a lightly sparkling water over a strongly carbonated one.
• Switch to still water later in the day if your stomach tends to feel tight by then.

If you have reflux or a gut condition such as IBS, fizzy drinks of any kind may make your symptoms worse, and health services such as the NHS suggest cutting down on fizzy drinks if they bring on bloating or heartburn. Still water is the easy swap. If bloating is frequent, painful or new, talk to a doctor rather than just changing your drink.

What about flavored and sweetened sparkling water?

Read the ingredients list, not just the front of the can. Three things change the picture.

1. Sugar or juice. Once a sparkling water has sugar or fruit juice in it, it is closer to a soft drink than to water. It still adds fluid, but it adds sugar too, and the sugar is the bigger concern for your teeth and for the afternoon energy dip.
2. Sweeteners. Cans marked "zero sugar" usually rely on non-sugar sweeteners. They count as fluid. The World Health Organization advises against relying on non-sugar sweeteners to control weight, but that guidance is about weight, not hydration. If you are trying to cut down on sweetness overall, plain or naturally flavored seltzer makes a better daily habit.
3. Acids. Citric acid is common in flavored versions, often listed near the top. It is the main reason flavored cans are harder on teeth than plain ones.

The simplest flavored sparkling water is one you make yourself: a slice of lemon, lime or cucumber in a glass of plain seltzer. Citrus slices add a little acid as well, so the "drink it, don't nurse it" habit still applies.

Does sparkling water hurt your bones?

This worry comes up often, and it comes from research on cola. A large US study, the Framingham Osteoporosis Study, found that cola was linked with lower bone density in older women, while other carbonated drinks were not. Cola contains phosphoric acid and caffeine. Plain sparkling water contains neither, and there is no good evidence that it harms bones.

If you have been told you have low bone density, your doctor is the right person to ask about your diet as a whole. For everyone else, the bubbles are not the problem.

Keeping a can at your desk

Sparkling water has one real advantage at a desk: many people simply find it nicer to drink than a glass of tap water that went warm and flat hours ago, so they drink more of it. A few things make it work better:

• Keep it cold. Carbon dioxide stays dissolved better in cold water, so a cold bottle holds its fizz longer once it is open. An insulated bottle helps on long days.
• Pour it into a clear glass. A can hides how much is left. A glass you can see is a reminder in itself.
• Keep it away from the Mac. A can tips more easily than a heavy glass, and a sweetened or flavored drink is worse on a keyboard than water. Keeping water on your desk without spilling it on your Mac covers placement, lids and what to do if it happens anyway.
• Use a bottle made for fizz. If you refill a reusable bottle with sparkling water, pick one that is built to hold carbonated drinks, and open it slowly.
• Let it replace the third coffee. A cold, fizzy drink has enough bite to feel like a treat, which makes it a good stand-in for the mid-afternoon cup.

The hard part, as usual, is not the can. It is remembering to open it. Notchpals, a Mac app that gives each kind of reminder to its own character, hands water to three of them: Melo, a watermelon, plus Puddle and Lolo, a seal pup and an axolotl. The one in your crew visits several times a day to suggest a drink, including once in the afternoon, between 2 and 5 PM, when the office coffee machine gets busy.

MeloAnother coffee? Nope. I'm a fruit, and I say water. Fruit knows.

Melo has no view on bubbles. Notchpals doesn't see what is in the glass or keep count of it, so still water, a can of seltzer or a mug of herbal tea all earn a Done. It picks a reasonable moment to ask and takes your word for the rest.