An investigation by The Sunday Telegraph reported the acid levels of popular juice drinks -- including one more acidic than vinegar.
Dr. Kathy Harley, dean of the dental faculty at the Royal College of Surgeons, said 50 percent of
5-year-olds now have signs of damage to their tooth enamel caused by excess acid in their diet.
Tooth enamel begins to be destroyed when acid levels in the mouth drop below 5.5 on the pH scale -- 7 is neutral -- while 1 is a strong acid.
Water has a pH of 7, and milk is just below at 6.8, but the investigation found "This Water," a product sold in Britain that contains lemons and limes that describes itself as a "juice drink blended with pure squeezed juices and pure spring water," had a level of 2.7 -- more acidic than cider vinegar, which has a pH level of 2.9.
The other fruit drinks tested included: Tropicana orange juice, Copella apple juice, Innocent smoothies, Capri Sun orange drink and Robinsons Fruit Shoot apple and blackcurrant low-sugar drink all had acid levels ranging from 3.3 to 3.8.
However, the most acidic beverage tested was Coca Cola, with a pH level of 2.5 and 12.5 teaspoons of sugar in a 17.5-ounce bottle, the Telegraph said.