The British Dental Association has urged the Coca Cola company to drop the spin on the 'healthy options' offered on its Christmas tour - given their sugar-free brands are more acidic than lemon juice and vinegar, and have helped leave nearly half of teens with dental erosion.
Coke PR teams have been attempting to deflect heavy criticism of their truck stunt, with a focus on their zero sugar varieties. Recent statements have described 90% of the drinks given out on the tours as 'zero sugar', and reflect wider strategy to put greater emphasis on their Diet Coke and Coke Zero brands.
Both Coke Zero and Diet Coke, like Classic Coke, contain phosphoric acid, which gives them their tart flavour. The clear, odourless chemical is also an effective rust remover - the reason why the drinks can restore the shine to old metal and coins.
Acidity is measured by its 'pH value', and tooth enamel can dissolve at any pH level lower than 5.5. Tests have given give Coke Zero a pH of 2.9 - lemon juice has a pH in the 2 to 3 range, most vinegars 2 to 3.5. Colas are carbonated, so freshly-opened cans also contain high quantities of dissolved carbonic acids.
Tooth enamel is irreplaceable. Regular cola drinkers can experience dental erosion, with reduced enamel thickness and changes in shape, texture and appearance of their teeth, together with pain and sensitivity. According to the last Child Dental Health Survey up to 44% of 15-year-olds showed signs of tooth surface loss, mostly attributed to erosion, on various tooth surfaces examined.
The Coca Cola tour is visiting 24 locations in 2018, down from 38 last year. The BDA is one of 83 organisations and health campaigners who signed an open letter co-ordinated by Sugar Smart calling on Coca-Cola to stop distributing sugary drinks.
The BDA's Health and Science Chair Russ Ladwa said: "Whether your Cola is sugary or sugar-free don't believe industry spin doctors when they claim there's a 'healthy option' for your teeth.
"Families across Britain are being marketed drinks more acidic than vinegar or lemon juice. When nearly half of teenagers are showing signs of dental erosion these brands have as little place as a Christmas tradition as their sugar-laden stablemates.
"It's welcome news that so many communities have stopped rolling out the red carpet to Coca Cola. We urge those that remain to show them the door in 2019."