Sugar intake should be halved to just five teaspoons a day, after scientists warned that treats which have traditionally been saved for birthdays or Christmas have become everyday staples.

A study by Newcastle University into the effects of sugar on our oral health recommends cutting down sugar to reduce tooth decay.

Since 1990 the World Health Organisation (WHO) has recommended that intake of “free sugars” should be less than 10 per cent of total energy (calorie) intake.

Free sugars are sugars that are added to foods by the manufacturer, cook, or consumer; plus those naturally present in honey, syrups, fruit juices and fruit concentrates.

Researchers recommend halving the threshold to less than 5 per cent of calories – around five teaspoons a day – would bring further benefits, minimising the risk of dental cavities throughout life.

They claim halving the 10 teaspoon level would allow people to ‘keep their teeth for life.’

Paula Moynihan, Professor of Nutrition and Oral Health at Newcastle University said: “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.

“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 per cent of the calories we eat would minimise the risk of dental caries throughout life.”

Experts also found that fluoride does not protect against cavities caused by sugar. While it does protect teeth, people living in areas with fluoridated water and or using fluoride toothpaste still got dental caries.

Professor Moynihan said: “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.

“Moreover, not everyone has good exposure to fluoride through drinking water and or toothpastes containing fluoride.”

Researchers looked at 55 dental health studies dating back to the 1950s.

The NHS currently recommends that foods that are high in sugar should be kept to a minimum.

High sugar diets are known to lead to heart disease and diabetes.

Added sugars shouldn’t make up more than 10% of the energy (calorie intake) you get from food and drink each day.

This is about 70g for men and 50g for women but it varies depending size, age and activity. More than 22.5g of total sugars per 100g is considered high for food.

Professor 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.”

The study was published in the Journal of Dental Research.