The healthiest seltzer is plain seltzer water with no added sweeteners, sodium, or flavors. It’s just water and carbon dioxide, nothing else. That simplicity is exactly what makes it the cleanest option among carbonated drinks. But once you start comparing brands, flavors, and types of sparkling water, the details matter more than you might expect.
Seltzer, Club Soda, and Mineral Water Are Not the Same
These three drinks sit on the same shelf but have meaningfully different ingredients. Seltzer is the simplest: water infused with carbon dioxide gas. No minerals, no sodium, no additives. Club soda starts with that same carbonated water but adds salts like sodium chloride, sodium bicarbonate, or sodium citrate to give it a slightly mineral, salty taste. Sparkling mineral water comes from a protected underground spring and naturally contains more than 250 parts per million of dissolved minerals like calcium, magnesium, and potassium.
If you’re watching sodium intake, those differences are significant. La Croix, a popular plain seltzer, contains zero milligrams of sodium. San Pellegrino and Topo Chico, both mineral waters, have about 40 milligrams per liter. On the extreme end, Vichy Catalan, a Spanish mineral water, packs 1,097 milligrams of sodium per liter. Most club sodas fall somewhere in between. For context, the daily recommended sodium limit is 2,300 milligrams, so a heavily mineralized water can eat into that budget fast.
Sparkling mineral water does offer a potential upside: those naturally occurring minerals contribute small amounts of calcium and magnesium to your diet. Plain seltzer contributes neither minerals nor sodium, which makes it the most neutral choice.
What “Natural Flavors” Actually Means
Most flavored seltzers list “natural flavors” as an ingredient, which sounds reassuring but deserves a closer look. Food chemists create natural flavors in a lab by extracting substances from plants or animals and recombining them to mimic specific tastes. They’re labeled “natural” because the source material comes from nature, not because they’re equivalent to squeezing fresh fruit into your glass. These extracts are designed purely for taste and contribute no vitamins, fiber, or other nutritional benefit.
A flavored seltzer with only carbonated water and natural flavors on the label is still a reasonable choice. The real concern is seltzers that also include sweeteners, juice concentrates, or citric acid. Some brands marketed as “sparkling water” contain added sugar or sugar alcohols, pushing them closer to soda territory. Always check the nutrition label: a healthy seltzer should show zero calories, zero sugar, and zero sodium (or very close to it).
Sweeteners Change the Equation
A growing number of sparkling water brands add non-nutritive sweeteners like stevia, monk fruit extract, or sucralose to create a sweet taste without calories. These sweeteners don’t raise blood sugar directly. But the long-term picture is less clear-cut. Some research suggests that regularly consuming artificially sweetened foods and drinks may not deliver the health benefits people expect compared to simply cutting out sweetness altogether. If your goal is the healthiest option, unsweetened seltzer avoids that uncertainty entirely.
Carbonation and Your Teeth
Dissolving carbon dioxide in water creates a mild carbonic acid, which makes seltzer slightly more acidic than tap water. That raises a reasonable question about tooth enamel. Research from the American Dental Association tested whether sparkling water erodes enamel more aggressively than still water using extracted human teeth. The result: the two were about the same in their effects on enamel. Plain sparkling water is, for all practical purposes, just water to your teeth.
Flavored seltzers are a different story. Citrus-flavored varieties often have higher acid levels, which does increase the risk of enamel damage over time. If you drink flavored seltzer regularly, choosing non-citrus flavors (like berry or cucumber) is a small move that reduces acid exposure. Drinking through a straw also limits contact with your teeth.
Bones, Bloating, and Digestion
You may have heard that carbonated water weakens bones. The evidence doesn’t support this for seltzer. A study published in the British Journal of Nutrition compared postmenopausal women who drank about one quart of carbonated mineral water daily against a group drinking the same amount of still mineral water. After eight weeks, bone turnover markers showed no difference between the two groups. Harvard Health Publishing concluded that drinking seltzer water doesn’t contribute to osteoporosis or increase fracture risk. The bone concerns are specific to cola, which contains phosphoric acid, a completely different ingredient that seltzer doesn’t have.
Carbonation can cause bloating and gas in some people, especially those with irritable bowel syndrome or acid reflux. The carbon dioxide expands in your stomach, which can trigger discomfort or worsen reflux symptoms. If you experience this, drinking smaller amounts or choosing a less aggressively carbonated brand can help. For most people, though, seltzer is well tolerated.
PFAS and Contaminant Concerns
Per- and polyfluoroalkyl substances, commonly called PFAS or “forever chemicals,” have been a concern in bottled water generally. The FDA tested 197 bottled water samples collected from retail locations across the U.S. between 2023 and 2024, including purified, artesian, spring, and mineral waters. Only 10 of the 197 samples had detectable PFAS levels, and none exceeded the maximum contaminant levels set by the EPA for drinking water. That’s reassuring, though it’s worth noting the testing covered bottled water broadly rather than seltzer brands specifically.
If minimizing contaminant exposure is a priority, you can also make seltzer at home using a countertop carbonation device and filtered tap water. This gives you control over both the water source and the absence of additives.
What About the Can Itself?
Most seltzer comes in aluminum cans, which are lined with a coating to prevent the metal from reacting with the liquid inside. Historically, that liner contained BPA, a chemical that can disrupt hormones. Many manufacturers have moved away from BPA, but the Environmental Working Group notes it remains unclear how widely aluminum beverage cans still use it. Some replacements, like BPS, raise their own hormonal concerns. If this worries you, glass bottles or home carbonation sidestep the issue entirely.
How to Pick the Healthiest Option
When you’re standing in the grocery aisle, here’s what to look for on the label:
- Ingredients: Carbonated water only, or carbonated water plus natural flavors. Nothing else.
- Calories and sugar: Both should be zero.
- Sodium: Zero or single-digit milligrams per serving.
- Sweeteners: None listed, including stevia, sucralose, monk fruit, or erythritol.
Brands like plain (unflavored) seltzer from any major manufacturer typically meet all of these criteria. Flavored options from brands that use only carbonated water and natural flavors are a close second. Sparkling mineral water is a fine choice too, especially if you want the trace minerals, but check sodium content if you’re on a low-sodium diet. Club soda, with its added salts, is the least “clean” of the group, though the sodium amounts are still modest for most people.
At its core, the healthiest seltzer is the one with the fewest ingredients. Plain carbonated water hydrates you, contains nothing your body needs to process or filter out, and poses no meaningful risk to your teeth, bones, or digestion. Everything added on top of that, whether it’s flavoring, sweetener, or minerals, is a tradeoff worth evaluating against your own health priorities.