Evidence That Daily Vinegar Ingestion May Contribute to Erosive Tooth Wear in Adults

The medicinal use of vinegar has ancient roots. Over 2000 years ago, Hippocrates used vinegar as a wound disinfectant, and, to combat persistent coughs, he combined vinegar with honey to make a remedy called Oxymel, which was used into the 19th century by physicians. ¹ In the 18th century, U.S. medical doctors used vinegar as a panacea to treat issues from poison ivy to croup to stomach ache. ² Today, in response to patient demand for natural remedies, vinegar has reemerged as a popular treatment for many ailments, and scientific investigations are demonstrating the efficacy of vinegar ingestion for certain conditions.

Numerous trials have demonstrated that vinegar has antiglycemic properties when ingested at mealtime as evidenced by two recent meta-analyses examining the attenuation of postprandial glycemia by vinegar. ^3,4 This effect is substantial, with a 40% reduction, on average, in the amount of glucose in the bloodstream during the 2-h period after meal ingestion, an effect attributed to the slowing of gastric emptying, the inhibition of starch digestion, and/or the enhanced uptake of blood glucose by muscle. ^{5 –7} Daily vinegar ingestion at mealtime also significantly reduced fasting blood glucose concentrations in individuals with prediabetes. ⁸ In animal models, vinegar has demonstrated antihypertensive and antiobesity effects. ^{9 –11} These physiological effects of vinegar are mediated by acetic acid, the defining ingredient of all vinegars, which comprises 4–6% of commercial vinegars.

As a highly acidic liquid with a pH slightly >3.0, vinegar is among the most acidic consumable substances. ¹² Frequent exposure to substances that are acidic in nature contributes to dental erosion, defined as the irreversible loss of dental hard tissue (enamel and dentin) caused by low intraoral pH in the absence of bacteria. ¹³ These exposures can be intrinsic or extrinsic in nature ranging from stomach acids to sodas to fruit juices, energy drinks, and vinegar, all resulting in the dissolution of teeth. ^{14 –16}

We recently recorded tooth wear in healthy adults participating in a randomized controlled parallel arm trial examining the effects of vinegar ingestion on insulin sensitivity and visceral fat reduction (see Jasbi et al. ¹⁷ ; registered at ClinicalTrials.gov, NCT03577834; ethical approval by the Institutional Review Board at Arizona State University, STUDY00005418). Twice daily for 8 weeks, participants randomized to the liquid vinegar group (VIN) were instructed to make a vinegar drink (two tablespoons of red wine vinegar [Mantova Red Wine Vinegar; Mantova, Broccostella, Italy] diluted in a cup of water) and consume immediately before meal ingestion. Participants randomized to the control group (CON) received a bottle of vinegar pills (Apple Cider Vinegar Tablets; NowFoods, Bloomingdale, IL) and were instructed to take one pill with food twice daily for 8 weeks. The liquid vinegar dosage provided 3.6 g of acetic acid daily in comparison with the vinegar pill that provided only a trace amount of acetic acid (0.045 g daily); furthermore, since the pill was quickly swallowed, the oral cavity of the CON participants was not exposed to the supplemental acid.

Participants completed a short survey to measure moderating and mediating factors that could contribute to dental enamel erosion at baseline and at the end of the trial at week 8 (score range for sample: 16–58). The survey included questions regarding acidic beverage consumption (frequency and amount of beverage consumed), acidic beverage practices (drinking from straw vs. can, etc.), presence of gastroesophageal reflux disease, factors attributing to hyposalivation such as dehydration and medication usage, xerostomia as a valid predictor of hyposalivation, and abrasion and attrition risk factors. ^16,18,19 A compliance calendar was completed by all participants and returned to investigators at the end of the trial. Study compliance was calculated as percentage of study days that the treatments were administered.

Participants were screened for erosive tooth wear using the basic erosive wear examination (BEWE) by a blinded registered dental hygienist at baseline and week 8. The BEWE was established by Bartlett et al. in 2008 as a simple, uniform, and repeatable way to measure and compare dental erosion in patients. ²⁰ The screening was conducted by dividing a participant's mouth into sextants. Each tooth in the sextant was examined and given a number ranging from 0 (no erosive tooth wear) to 3 (hard tissue loss ≥50% of surface area); only the highest number in each sextant was recorded. Teeth that had full restorations were eliminated from the sextant. The recorded numbers from each sextant were then calculated as a summative score to give one total erosive score (scale range: 0–18).

A repeated measures analysis of variance test was conducted to assess time x group interaction. Differences between means were evaluated using the Mann–Whitney U test. The IBM SPSS Statistics for Windows program (version 25.0; IBM Corp, Armonk, NY) was used for all analyses, and significance was set at P < .05. Participant characteristics, study compliance, moderator variable scores, and BEWE scores did not differ between the VIN and CON groups at baseline (Tables 1 and 2). The score for moderator variables related to tooth erosion did not differ between groups over time. However, there was a significant time x group interaction for BEWE scores, and over the course of the 8-week trial, the BEWE score increased 18% for VIN participants (P = .038) but were unchanged for CON participants (Table 2). Overall, the BEWE score of participants at baseline was 4, which equates to a low-to-medium risk for erosive tooth wear according to recent epidemiological surveys in Israel and Iceland. ^21,22 BEWE scores from 7 to 14 indicate high risk and suggest a need for treatment.

These data suggest that the daily ingestion of vinegar as a diluted drink may affect oral health, a risk also noted for colas and fruit juices. ^14,16 Cairns et al. demonstrated that the titratable acidity of beverages was reduced in proportion with the dilution ratio and concluded that that erosive potential of beverages can be reduced by dilution with “considerable amounts of water.” ¹⁸ Hence, it is likely important that medicinal vinegar be ingested in a diluted form. Moreover, O'Toole et al. demonstrated that the risk of erosive wear was nearly doubled when acidic beverages were consumed between meals in comparison with with meals, ¹⁹ suggesting that vinegar ingestion should be at mealtime. In vitro vinegar was 2–7 times more likely than soft drinks to result in dental erosion based on mineral release from teeth, ²³ and epidemiological studies have shown direct relationships between the frequency of acidic beverage consumption, including vinegar acids, and dental erosion. ^14,16

Limitations to this study include the short duration of the trial and a small sample size: both are factors restricting the generalizability of the results. In addition, only examining macroscopic changes to enamel is a limiting factor. Although a previous study has demonstrated microscopic changes in the dental enamel of participants after 4 weeks of consuming an acidic beverage, ²⁴ there are no studies to date clarifying the typical time it takes to see macroscopic changes in dental enamel. A longer study with multiple time points of observation by multiple trained professionals would clarify the potential erosive properties of vinegar on teeth at the macroscopic level. Given the current popularity of vinegar as a medicinal agent, attention to oral health is warranted. Vinegar should be diluted and ingested with food. Also, trials have demonstrated that use of a straw when drinking acidic beverages reduces risk for tooth wear. ²⁴