Cutting 'free sugars' tackles decay
People should lose their sweet tooth if they want the best chance of keeping a full set of molars, say scientists.
Researchers found that cutting added sugar from the diet greatly reduces levels of tooth decay.
They urged members of the public to keep to World Health Organisation (WHO) advice to lower intake of "free sugar" to less than 10% of total calorie consumption.
Free sugars are sugars added to foods by manufacturers, cooks or consumers. They also include sugars naturally present in honey, syrups and fruit juices and concentrates.
The study, commissioned by the WHO and conducted by scientists at the University of Newcastle, found that keeping below the 10% threshold led to significantly less caries, or tooth decay.
Going further and halving the sugar limit to less than 5% of daily calories - around five teaspoons a day - would minimise the risk of dental cavities throughout life, say the researchers.
Study leader Professor Paula Moynihan, an expert in nutrition and oral health, said: "People now expect to keep their teeth into old age and given that the effects of sugars on our teeth are lifelong, then limiting sugars to less than 5% of the calories we eat would minimise the risk of dental caries throughout life.
"In the past, judgments on recommended levels of free sugars intake were made based on levels associated with an average of three or fewer decayed teeth in 12-year-olds. However, tooth decay is a progressive disease. By looking at patterns of tooth decay in populations over time, we now know that children with less than three cavities at age 12 go on to develop a high number of cavities in adulthood.
"Part of the problem is that sugary foods and drinks are now staples in many people's diet in industrialised countries, whereas once they were an occasional treat for a birthday or Christmas. We need to reverse this trend."
The scientists found that people living in areas with fluoridated water or using fluoride toothpaste still suffered from tooth decay.
"Fluoride undoubtedly protects the teeth against decay but it does not eliminate tooth decay and it does not get rid of the cause - dietary sugars," said Prof Moynihan. "Moreover, not everyone has good exposure to fluoride through drinking water and/or toothpastes containing fluoride."
The Newcastle researchers pooled together results from 55 studies linking sugar and tooth decay dating back to 1950.
They used analytical techniques which take into account factors such as the consistency of results, the size of the effect, evidence of a larger effect with greater exposure (dose response), and the strength of the association.
Prof Moynihan added: "The public need better information on the health risks of sugary foods and drinks and there needs to be clearer information on the levels of sugars in our foods and drinks. We need to make it easier for people to make healthier choices when it comes to sugars by ensuring that options lower in added sugars are made widely available in schools, shops and the workplace."