Refined starches: The surprising food now being blamed for an 'epidemic' of tooth decay

When it comes to rotten teeth, there's a new culprit on the block and it's bad news for many Kiwi fans of toast and sandwiches.

We all know about sugar but new research from the University of Auckland and Starship Children's Hospital shows there are some less obvious foods that could be causing tooth decay.

Epidemiologist Dr Simon Thornley says the results of his latest study were a real eye-opener. While sugar has long been the villain, there's a new baddie for teeth - refined starches.

"Well the findings did surprise me, I mean I've been very focused on sugar," he tells Newshub.

"White bread really came through strongly, there was a lot of white bread in kids' diets and that was very strongly associated with kids getting rotten teeth."

The study found frequent intake of some foods - including white bread, refined breakfast cereals and noodles - was associated with a greater number of cavities.

The refined starch provides fuel for bacteria in the mouth, causing the plaque to build up, leading to the acid which erodes the enamel.

The Starship Foundation funded the study after seeing thousands of children facing hospital treatment every year because of tooth decay. It's the leading cause of avoidable hospital treatment for children in this country.

"There's a silent epidemic of rotten teeth... this costs the country millions of dollars each year and it's entirely preventable," Dr Thornley says.

Eating wholemeal or whole wheat bread, brassica vegetables like broccoli and cauliflower, and cheese, were associated with fewer cavities.

It's hoped more toothbrushing and eating less refined starches will lead to less mouth surgery.

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