Funded by the Functional Water Foundation in Japan, the research was built upon increasing incidences of dental erosion among athletes, infants, and the elderly due to their frequent consumption of acidic foods and drinks.
In Japan, many of these acidic foods and drinks such as sports drinks are consumed for preventing heat stroke and dehydration, while fermented foods like Japanese pickles are said to promote the absorption of nutrients into the body.
Dental erosion is also prevalent worldwide, so eliminating these acidic foods and drinks are not a viable solution.
The critical pH of enamel decalcification is considered to be approximately 5.5 to 5.7, so acidic beverages will increase the likelihood of dental erosion or enamel demineralisation or decalcification.
So, researchers suggest alkaline ionised water as a potential approach for preventing dental erosion by bringing the pH levels back to near neutral levels.
Alkaline ionised water is weakly alkaline, with a pH of 9 to 10, and is approved for drinking by the Japanese Ministry of Health, Labor and Welfare. It has also been studied for improving gastrointestinal symptoms and oral health.
Test on cola and sport drink
This study published in Nutrients covered two acidic beverages often consumed in Japan, cola and sports drink, with pH values of 2.2. and 3.3 respectively.
Five participants were involved in this research, which required them to swish 50mL of the acidic beverages in their mouth with the pH electrode attached to the surface of the enamel, continuously measuring until the pH was near neutral (value = 7).
To test the effect of the alkaline ionised water, subjects ingested the acidic beverages, followed by the alkaline ionised water in the same manner and pH was similarly continuously measured.
In the cola only test, the average time for enamel pH to reach 7 was about 6 to 8 minutes.
Similarly, in the sport drink only test, the average time for enamel pH to reach 7 was about 10 to 12 minutes.
When subjects took alkaline ionised water after consuming either acidic drink first, it took about 15 to 20 seconds to reach a pH of 7, drastically reducing the time.
The experiment was also tested on tap water (pH 6.7) instead of alkaline ionised water, revealing the same pattern, although it took more time, about 9 to 12 minutes to reach neutral pH.
One observation was the slower rate of pH increase by the alkaline ionised water in the sports drink test, compared to cola.
“Although the cause is unclear, it has been reported that the pattern of changes in the enamel surface pH due to acidic beverages differs depending on the type of beverage. Moreover, this difference seems to be important in assessing the risk of an erosive effect on teeth. That is, the risk of dental erosion may be higher with sports drinks than cola,” researchers wrote.
These findings confirmed that the pH level of enamel surface decreases immediately after ingestion of acidic beverages like cola or sports drinks, but the ingestion of alkaline ionised water rapidly increases the pH levels back to neutral.
Researchers said, “Alkaline ionised water was shown to be useful in preventing dental erosion caused by acidic beverages. We recommend the intake of a sufficient amount of alkaline ionised water after ingesting acidic foods and drinks.”
“In the future, we plan to add other acidic beverages and further investigate the changes in the enamel pH and the effects of alkaline ionised water on them when they are ingested.”
“The Onset of Dental Erosion Caused by Food and Drinks and the Preventive Effect of Alkaline Ionized Water”
Authors: Tsutomu Sato, et al.