Are Sugar-Free Sodas and Sparkling Waters Bad for Your Teeth?

Last updated: June 2026 | Reviewed against JADA Foundational Science 2022 sugar-free beverage erosion study, Preprints 2025 systematic review (38 studies), brand-specific pH testing, and ADA guidance

If you switched from regular Coke to Diet Coke, or from soda to LaCroix, for the sake of your teeth, this article is important reading. The assumption that sugar-free means safe for enamel is one of the most widespread misconceptions in everyday dental health, and it leads to significant ongoing enamel damage that is preventable once you understand what is actually happening.

The core correction is simple: enamel erosion is caused by acid, not sugar. Sugar feeds bacteria that produce acid, which is one pathway to enamel damage. But extrinsic acid from beverages is a separate, direct pathway that operates regardless of whether sugar is present. Removing sugar from a beverage changes neither its pH nor the acid that determines its erosive potential.

Sugar vs. Acid: Two Different Enamel Problems

Enamel damage from diet happens through two distinct pathways that are frequently confused because they often occur together in the same beverages.

The bacterial pathway: oral bacteria ferment dietary sugars and produce lactic acid as a metabolic byproduct. This lactic acid drops plaque pH below the 5.5 enamel demineralization threshold, creating an acid attack that lasts 20 to 40 minutes per eating occasion. This is the caries pathway described by the Stephan curve, and it is the one that sugar specifically causes. Removing sugar from a beverage eliminates this pathway.

The direct acid pathway: acids in beverages contact enamel directly and dissolve hydroxyapatite mineral without requiring any bacterial involvement. This is the erosion pathway. Phosphoric acid in colas, citric acid in flavored drinks and juices, carbonic acid in carbonated beverages, and malic or tartaric acid in wines all create this direct acid attack on contact with tooth surfaces. The acid content of a beverage is independent of its sugar content. Removing sugar from a beverage does not change the acid.

When people switch from regular soda to diet soda, or from juice to flavored sparkling water, they eliminate the bacterial fermentation pathway (no sugar to ferment). They do not eliminate the direct erosion pathway. In fact, the beverage they switch to often has essentially identical acid content to what they left behind. The sweetener changes. The enamel risk does not.

Diet Soda: Why It's as Erosive as Regular Soda

The erosive potential of a cola drink is determined by its pH and the type of acid it contains, not by whether it contains sugar. Coca-Cola and Diet Coke contain the same primary acid: phosphoric acid. Both have a pH in the range of 2.5 to 3.0. When researchers measure enamel erosion from cola exposure, the results consistently show that regular and diet versions of the same cola cause comparable or similar enamel surface loss.

An in vitro study comparing regular cola, diet cola (light cola), and modified versions with adjusted pH and sweetener content found: "Independently of the cola modifications, all groups promoted similar hardness change of enamel surface." When the pH was adjusted upward by adding base, enamel loss was reduced. When the pH was adjusted downward, enamel loss increased. The sweetener (aspartame versus sucrose) had a smaller effect than the acid. The key variable was the acid, not the sugar.

The ADA itself is clear about this mechanism. A 2022 ADA press release summarizing the JADA Foundational Science research stated: "Sweetener type was less of a factor, as it was the acid in the beverage that eroded the enamel." It found that acids in both sugar-containing and sugar-free sodas caused enamel erosion in extracted human teeth.

There is one narrow dental benefit of diet soda over regular soda: it does not provide the fermentable substrate that feeds acid-producing bacteria, so it does not cause the bacterial acid pathway described by the Stephan curve. A diet soda does not trigger cavity formation through the bacterial route. But diet soda absolutely does cause direct acid erosion of enamel, and over years of heavy consumption, this produces the same pattern of enamel thinning, sensitivity, and tooth surface loss seen in heavy regular soda drinkers. The cavities may not form; the erosion will.

Carbonic Acid vs. Citric Acid: Not All Fizz Is Equal

Not all acid in carbonated beverages is the same, and understanding the difference between carbonic acid and citric acid is the key to making sense of why plain sparkling water is genuinely different from flavored sparkling water and diet soda.

Carbonic acid (H2CO3) forms when carbon dioxide dissolves in water. It is a weak, diprotic acid. Critically, it is transient: when a sparkling water is opened and the CO2 begins to escape, the carbonic acid dissipates as the bubbles leave. A flat sparkling water is essentially just water. This transient nature means the acid contact time on enamel is naturally limited by the rate at which carbonation escapes, and the acid does not persist in the oral environment the way other acids do.

Citric acid is a different substance with different properties. It is a triprotic organic acid with high titratable acidity: it contains more total acid per volume than its pH alone would suggest, and it must be neutralized by a larger amount of base before its erosive effect is exhausted. Critically, citric acid also chelates calcium directly from enamel, binding to calcium ions and pulling them out of the hydroxyapatite crystal structure through a mechanism that operates in addition to, and independently of, simple proton donation. This calcium-chelating mechanism means citric acid is more erosive than carbonic or phosphoric acid at the same pH value.

The 2025 Preprints systematic review (38 studies, 2013-2025) made this distinction explicit: "Dental professionals should recognize that not all acids are equal. Citric, malic, tartaric, and acetic acids (common in fruits/fermented drinks) tend to be more erosive than carbonic or phosphoric acids." It also noted the counterintuitive consequence: "Sprite (citric acid soda) is more erosive than Coke (phosphoric acid soda)" despite similar or lower pH, precisely because citric acid's titratable acidity and calcium-chelating mechanism sustain the erosive effect longer.

The practical implication: plain sparkling water (carbonic acid only, transient) is genuinely lower erosion risk than flavored sparkling water or diet soda (citric acid, persistent, calcium-chelating). The fizz itself is less dangerous than the flavoring acid that accompanies it in most commercially flavored sparkling waters.

Plain Sparkling Water: The Honest Risk Profile

Plain sparkling water (unflavored seltzer, unflavored mineral water, unflavored sparkling water) has a genuinely more favorable dental profile than most people assume when they read alarming headlines about carbonated water, and a less favorable one than the "it's just water with bubbles" dismissal suggests.

The pH of plain sparkling water ranges from approximately 4.18 to 5.87 across commercially measured brands, according to multiple beverage pH studies. Most plain sparkling waters cluster in the 4.5 to 5.5 range. Some brands (Perrier measures pH 5.22 to 5.46 in various tests) sit comfortably below the 5.5 threshold but are very close to it. Others may vary by lot and temperature.

The ADA's position, based on the JADA Foundational Science 2022 research, is that plain sparkling water is "generally safe for teeth, with negligible erosion under normal consumption." The 2025 Preprints systematic review confirmed: "Unflavored seltzer water produces minimal enamel softening, often not significantly more than tap water in short exposures."

The key qualifiers on "generally safe" are: normal consumption patterns (defined sittings with meals rather than continuous all-day sipping), adequate saliva, and no additional citric acid or flavoring. For people who sip plain sparkling water continuously throughout the day as their primary hydration, the accumulated acid contact time increases risk. For people with dry mouth, reduced salivary buffering makes the mild acid more significant than it would be in a person with healthy salivary flow.

The realistic verdict: plain sparkling water is a low-risk beverage for most adults drinking it in normal patterns. It is not equivalent to plain water. It is not negligible. It is a low but non-zero acid exposure that adds up with frequency and sipping duration.

Flavored Sparkling Water: The Category People Underestimate

Flavored sparkling water is a categorically different product from plain sparkling water, even when both carry "sparkling water" in the name. The flavoring in virtually all commercial flavored sparkling waters comes from citric acid, natural flavors that contain organic acids, or both. The pH drops accordingly.

Brand-specific testing has produced consistent results. CBC Marketplace tested Bubly grapefruit (pH 3.86), LaCroix (pH 4.71), and Perrier (pH 5.46). ScienceDirect beverage erosion studies found LaCroix Cran-Raspberry at pH 3.84, Polar Seltzer Lemon at pH 3.71. Independent lab testing of popular flavored sparkling waters has found pH levels between 2.74 and 3.34 in some products, with erosive potential comparable to or exceeding pure orange juice in controlled exposure studies.

This is not a minor distinction. The difference between plain sparkling water at pH 5.0 and LaCroix Cran-Raspberry at pH 3.84 is not the same brand slightly more flavorful. On the logarithmic pH scale, pH 3.84 is over 10 times more acidic than pH 5.0, and the citric acid responsible for that acidity is more erosive than carbonic acid at any pH value. A person sipping flavored sparkling water all day is creating the same sustained enamel erosion environment as a person sipping orange juice all day. Both may have zero sugar. Both are equally damaging to enamel from the acid erosion standpoint.

The 2025 Preprints systematic review captured this precisely: flavored sparkling waters, marketed as "zero-calorie, guilt-free refreshers," are "drastically better than sugar sodas for caries, but can contribute to erosion if consumed frequently, something many patients and even some dentists may not realize."

What the 2022 JADA Study Actually Found

The most comprehensive peer-reviewed evidence specifically on sugar-free beverages and enamel is the 2022 JADA Foundational Science study, published in the ADA's open-access journal and covered in an ADA press release. The research is worth understanding in detail because it directly tested the brands people actually drink.

Researchers soaked recently extracted human teeth in seven sugar-free beverages and one regular soda (as a reference) for 24 hours, which the researchers considered representative of approximately one year's worth of beverage exposure. The products tested included Coca-Cola (regular, as reference), Zevia Cherry Cola (sugar-free soda, pH 2.68), LaCroix Cran-Raspberry (flavored sparkling water, pH 3.84), Polar Seltzer Lemon (flavored sparkling water, pH 3.71), Perrier (plain mineral sparkling water, pH 5.22), Smartwater (still water), Dasani (still water), and Alkaline 88 (alkaline still water, pH 8.9).

The findings were clear. Measuring enamel and dentin erosion, they found that all except the non-carbonated, non-flavored bottled waters caused measurable erosion. Zevia (sugar-free soda) and LaCroix (flavored sparkling water) caused significant dentin erosion. Perrier, despite being a sparkling water, also caused measurable erosion, though the researchers noted it was lower than the more acidic products. Plain still waters (Smartwater, Dasani) and alkaline water showed no erosion. The ADA concluded: "Sweetener type was less of a factor, as it was the acid in the beverage that eroded the enamel."

This study is the single most definitive piece of evidence on the question this article addresses. It directly tested US-market sugar-free beverages on extracted human teeth and found that the "healthy" alternatives people reach for in place of regular soda or juice erode enamel, just through acid rather than sugar.

Why How You Drink Matters More Than the Brand

Even among the higher-risk products on this list, the pattern of consumption changes the actual enamel damage significantly. Two variables dominate.

Duration of contact. Every sip resets the Stephan curve acid-recovery clock. Sipping LaCroix continuously for two hours while working means the enamel is exposed to pH 3.84 acid for two hours plus a recovery window, with saliva never fully catching up. Drinking the same can of LaCroix in 10 minutes creates one acid event with one recovery window. The flavored sparkling water is the same. The enamel damage is dramatically different. The 2025 Preprints systematic review specifically advised: "Don't sip a lemon seltzer all afternoon; finish it and then rinse."

Meal context versus between-meal consumption. Consuming acidic beverages with a meal provides more salivary buffering, food that buffers acid, and the natural clearance that eating stimulates. Sipping flavored sparkling water between meals, in the absence of any salivary stimulus or buffering food, creates a more prolonged and less buffered acid challenge than the same drink with dinner. The ADA guidance advises consuming acidic beverages with meals specifically for this reason.

For the full Stephan curve mechanism explaining why contact duration is the key variable, see our dedicated explainer on the Stephan curve. For how these same principles apply to the full range of beverages, see our complete drinks pH ranking.

The After-Drink Window: What to Do

If you drink diet soda, flavored sparkling water, or plain sparkling water, the acid attack happens regardless of what you know about it. The question is what happens in the 20 to 40 minutes after you finish drinking, when saliva is working to buffer the acid and pH is recovering toward the 5.5 enamel safety threshold.

Rinsing with plain water immediately after finishing the drink dilutes residual acid and speeds clearance. Do not brush: acid softens enamel temporarily, and brushing on softened enamel removes mineral through abrasive wear. Wait at least 30 minutes.

Chewing remineralizing gum for 10 to 20 minutes after an acidic drink is the most effective single intervention for the recovery window, for the same reason it is recommended after meals. The chewing motion stimulates the masticatory salivary reflex, producing stimulated saliva at pH approximately 7.8 with high bicarbonate concentration. This alkaline, high-buffering saliva neutralizes the residual acid faster than resting saliva alone, shortening the time enamel spends below pH 5.5. Manning and Edgar (Br Dent J, 1993) confirmed that chewing sugar-free gum significantly accelerated pH recovery after acid exposure. The ADA specifically endorses sugar-free gum for this acid-neutralization role.

Xylitol in the gum adds an independent antibacterial effect against S. mutans, relevant even for sugar-free drinkers because the oral microbiome still contains these bacteria regardless of sugar intake. Nano-HAp in functional gum delivers enamel mineral during the Phase 3 recovery window when enamel is most receptive to remineralization. For how these ingredients work together on enamel, see our article on what nano-hydroxyapatite is.