By RefineNutrition.org Editorial Team
A “sugar-free” label answers one question about your teeth: whether the product gives cavity-causing bacteria sugar to work with. It does not answer a second question: whether the product is acidic enough to wear away enamel on its own. Those are two different mechanisms, so a chewable supplement can be sugar-free and still acidic.
In a 2024 lab study of six children's chewable vitamins, every product tested was acidic, and five of the six caused significantly more weight loss in enamel samples than plain water did. That finding deserves attention, and it is also narrow. Here is what it shows, what it can't show, and how to read a label with it in mind.
Why “sugar-free” and “acid-free” are different claims
Cavity formation involves acid made by bacteria in the mouth, which is why sugar gets so much attention. Dental erosion is a different, chemical process: acid touches the tooth and dissolves mineral directly, with no plaque bacteria involved. The 2024 study defines erosion this way, and the American Dental Association's MouthHealthy page makes the same point from the consumer side. Sugar isn't the only dietary factor that can damage teeth, and acidic foods and drinks wear away enamel.
The ADA also states that tooth erosion is permanent. That is why this article won't suggest any product or habit can rebuild enamel. Once it's worn, the practical goal is to limit further wear.
The ADA gives an example from drinks: sugar-free sodas can still be acidic because of carbonation. That example is about beverages, not supplements, but it shows why “sugar-free” can't stand in for “gentle on enamel.”
What the chewable-vitamin study found
Researchers at Mahidol University in Thailand tested six commercially available children's chewable vitamins: three vitamin C-only products and three multivitamins. They ground each tablet, mixed it with 3 mL of deionized water, and measured pH. Then they cycled small pieces of enamel from extracted human premolars between the vitamin solution and artificial saliva for 14 days, with two one-hour exposures a day. They based that schedule on the products' label directions of one tablet in the morning and one in the evening. The enamel pieces were weighed before and after.
- Every product was acidic. The pH ranged from 2.99 to 4.77, compared with 6.12 for the water control. The authors cite 5.5 as the critical pH for enamel, and all six products fell below it.
- Five of six caused significantly more enamel weight loss than water. The exception was one multivitamin, which did not differ significantly from the control.
- The vitamin C-only products did worse than the multivitamins. Under the electron microscope, enamel exposed to the vitamin C products was the most corroded.
- Lower pH generally meant more erosion. That held across the six products, with a correlation of -0.806. The two multivitamins containing calcium did not follow the pattern as closely: they lost less enamel than their pH alone would predict.
The authors suggest the minerals in those two multivitamins, such as calcium, iron and magnesium, may aid remineralization or reduce demineralization. That is their interpretation. The study did not test it directly.
What the study can't tell you
This is where most of the useful caution lives.
- It was a lab model, not people. The tablets were dissolved, not chewed. The authors acknowledge the model did not capture how saliva flow clears the mouth or how saliva buffers acid. How closely the results match real-life chewing is unknown.
- It tested six specific children's products. Gummies, adult chewables, and other formats were not tested. Formulations also change over time, so these results describe those products as tested, not every chewable on the shelf. The same goes for older reports. The authors cite a small number of case reports, including one from 1983, and an older report can't be assumed to describe today's products.
- Sweeteners weren't the focus. The main text of the paper doesn't address them, so it can't tell you whether a sugar-free version behaves differently.
- The evidence base is thin. The authors note that very few case reports link chewing vitamin tablets to erosion, and they state that no earlier research had examined chewable supplements as crushed, directly contacting products.
- The numbers are small. There were six products and six enamel samples per group. The pH-and-erosion relationship is a pattern across six items, not a rule for the category.
Why the chewable format is the part worth noticing
The study's authors point out that chewables, because they are crushed and chewed, contact tooth surfaces directly. Two things follow from that, and the study didn't measure either for real-world use:
- How long the product lingers. Contact time matters for any acid. The study modeled one-hour exposures but did not measure how long a chewable actually stays in the mouth.
- How often you take it. The study modeled two exposures a day because that's what the labels suggested. A product taken more often means more contact episodes.
A label-reading guide for chewables
No label gives you a pH. It can still point you toward better questions.
Sweetener
- What it tells you: whether sugar is added, and which sweeteners or sugar alcohols are used.
- What it can't tell you: how acidic the product is. A sweetener line speaks to the sugar question only.
Acids and flavorings
- What it tells you: whether the ingredient list includes ascorbic acid (vitamin C), citric acid, malic acid, or fruit flavors such as lemon, apple or pineapple. The study's authors suggest these could be sources of acidity in chewables.
- What it can't tell you: how much acid the product contributes, or its pH. Seeing these ingredients is a reason to ask, not proof of harm. Not seeing them is not proof of safety.
Added minerals
- What it tells you: whether the product contains calcium or other minerals. In the study, the two calcium-containing multivitamins showed less erosion than their pH alone would predict.
- What it can't tell you: that a mineral-containing product is protective. That was a pattern in two products, and the explanation is the authors' hypothesis.
Format
- What it tells you: whether the product is designed to be chewed, dissolved, or swallowed.
- What it can't tell you: whether a gummy, a chewable tablet, and a lozenge differ in enamel contact. The study tested chewable tablets only. Follow the label's directions for the format, and don't switch on your own. If you're considering a different form, ask a pharmacist.
Directions
- What it tells you: how many tablets, how often, and whether to take them with food or water.
- What it can't tell you: whether taking it with a meal changes enamel exposure. The ADA suggests eating acidic foods such as citrus and tomatoes as part of a meal rather than by themselves, but no one has tested whether that carries over to chewable supplements. Follow the label, and ask your dentist or pharmacist before changing how you take a product.
What no label can tell you
- The product's actual pH.
- How long it stays in your mouth, and how your saliva handles it.
- Whether results from one tested product apply to another, or whether lab findings would show up in your own teeth.
Practical steps that fit what's known
The ADA offers general erosion-prevention advice for acidic foods and drinks. These tips haven't been tested on chewable supplements specifically, so treat them as general habits to discuss with your dentist:
- Rinse your mouth with water after something acidic.
- Wait about an hour before brushing after acidic foods, which gives saliva time to wash acids away and let softened enamel re-harden.
- With acidic drinks, the ADA advises sipping and swallowing rather than swishing or holding the liquid in your mouth.
- Chew sugarless gum that carries the ADA Seal of Acceptance. The ADA says it keeps saliva flowing.
When to ask a dentist or pharmacist
Bring up your chewable supplement at your next dental visit, especially if it's taken regularly or given to a child. The ADA lists sensitivity to hot, cold or sweet drinks and yellowing teeth as possible signs of erosion. A dentist can evaluate what's going on in your mouth, which no article can.
If a doctor or dietitian prescribed or recommended a supplement, don't stop or change it because of this article. Ask your clinician or pharmacist whether a different form or timing is an option for you.
Sources checked
- American Dental Association, MouthHealthy: Dietary Acids and Your Teeth
- Lertsooksawat W, et al. Erosive potential of children's chewable vitamin supplements: an in vitro investigation. J Dent Res Dent Clin Dent Prospects. 2024;18(4):278-283. doi:10.34172/joddd.41791
This article is for educational purposes only and is not dental, medical, or nutritional advice. Talk with a dentist, pharmacist, or other qualified professional about your own situation.