The biggest dietary driver of tooth decay is sugary drinks, and other countries have taken bold policy action to counter this. In the wake of compelling new research and a powerful snub by a sports superstar, it’s time for New Zealand to step up, writes Boyd Swinburn.

We’re constantly reminded of the urgent need to improve the oral health of children in this country. Wide, confident smiles free of tooth decay are a strong sign of children’s underlying wellbeing. 

It’s been a busy few weeks, starting with the Auckland DHB apologising to the 2,000 children waiting in pain for dental treatment and tooth extractions. A week later football star Cristiano Ronaldo snubbed the sugar-laden Coca-Cola placed in front of him at a post-game press conference, wiping $5.6 billion off Coke’s share value before the conference ended. 

These events come as powerful new research from Mexico emerges showing an immediate decline in rotten teeth following a tax on sugary drinks and unhealthy processed foods. 

The extent of New Zealand children’s declining oral health was revealed in an Official Information Act request showing that between 2010 and 2019, 55,571 children went under the knife for dental surgery under general anaesthetic. 

The documents put the average cost per surgery as $2,600 per surgery, meaning a sombre total of $146,484,600. And that is just the dollar cost to taxpayers. It’s not counting the pain and suffering of those children while they wait for surgery or the ongoing psychological and social costs of living with either rotten teeth or extracted teeth.

On the action side, Auckland DHB has committed to clearing the backlog of the waiting list and associate health minister Ayesha Verrall has taken the long-overdue step of placing the responsibility for fluoridating water supplies in the hands of the director general of health, as a core public health action, rather than in the hands of local councils, where it has been a political football for decades.

On the inaction side, top recommendations from the World Health Organisation to improve children’s nutrition have been studiously ignored by successive governments. In particular, levies on sugary drinks manufacturers and restrictions on marketing unhealthy foods to children are always high priority recommendations to improve child nutrition problems like dental caries and obesity.

More than 45 countries and jurisdictions have implemented health levies on the sugary drinks industry and this policy now has a stack of compelling evidence backing its effectiveness. 

The research paper recently published by the Mexican Center for Research on Nutrition and Health found the prevalence of dental cavities dropped immediately upon the implementation of a tax on sugary drinks and unhealthy foods.

It is astounding just how rapidly the number of dental cavities per child plummeted. Outpatient appointments for rotten teeth, which had been rising for the six years before the tax, substantially decreased over the subsequent four years. 

We know how effective the Mexican taxes have been in reducing consumption of sugary drinks and now we now know just how fast that shows up in reduced dental caries. 

While a lot of ultra-processed foods contain sugars and simple carbohydrates, we know that the biggest dietary driver of tooth decay is sugary drinks – fruit juice, Raro, Coca-Cola, Powerade and so on. Sugary drinks hit hard in two ways. They trigger a chemical reaction that leads to tooth decay and the acidity levels of the drink itself wears off tooth enamel. Nearly 52% of all drinks sold in New Zealand contain added sugar. It sells better. Many of these drinks are promoted by sports stars, which makes Ronaldo’s snubbing, and subsequent share value drop, more poignant. 

These drinks also have other health detriments and lead to childhood obesity. The Unicef World’s Children report in 2019 showed that New Zealand had the second highest prevalence of childhood obesity in the OECD countries, just behind the United States. 

Other countries have taken bold policy action to improve the healthiness of food environments. Chile introduced the world’s strictest restrictions on advertising unhealthy foods and beverages. Front-of-packet warning labels are affixed to drinks with a stop sign stickered to the front saying “high in sugar”. TV marketing restrictions are also in place. Toys and cartoon characters are no longer allowed to be used to market junk food to children.

The UK not only has a very effective levy on sugary drinks manufacturers, but is also now poised to ban online food marketing to children and supermarket price promotions of unhealthy food. A recent survey of Pacific Island countries showed that three-quarters of them had implemented taxes on sugary drinks. 

While kids might love sports stars like Ronaldo, their teeth would love Jacinda to have a “Ronaldo moment” and do something serious about sugary drinks in Aotearoa. 

Boyd Swinburn is a professor of population nutrition and global health at the University of Auckland, and chair of Health Coalition Aotearoa.