For 100 years it has been added to toothpaste to make your teeth tougher. Now, councils should consider adding fluoride to drinking water to improve people’s dental health, according to the Government’s public health advisers.

The first ever national report examining the impact of water fluoridation on children, published by Public Health England (PHE), found that the measure has significantly reduced tooth decay and hospital admissions for dental problems.

Researchers measured the dental health of five-year-olds with baby teeth and 12-year-olds with adult teeth from fluoridated and non-fluoridated areas.

They found that there were 45 per cent fewer children aged between one and four admitted to hospital for tooth decay in fluoridated areas, while levels of general tooth decay were 15 per cent lower for five-year-olds and 11 per cent lower for 12-year-olds. In more deprived areas, the impact was even more striking.

The study also showed a statistically significant reduction in incidences of kidney stones and bladder cancer in areas where fluoride had been added to drinking water, which the agency said was “potentially interesting” and merited further research. But it cautioned that it was too early to tell if the altered water had a “protective effect”.

In England, 15 out of 152 local authorities have water fluoridation schemes in place, covering six million people. The process sees the level of fluoride being adjusted to one milligram per litre, or one part per million.

Attempts by local authorities to introduce similar schemes have caused controversy in the past, amid suggestions it can increase the risk of some cancers, hip fractures and Down’s syndrome. But the PHE report appears to strike down such claims, concluding that the process is a “safe and effective” measure which carries no threat of harm.

“There is a good deal of speculation about water fluoridation schemes. This report provides new data which is direct evidence of the safety and efficacy of water fluoridation in England,” said Professor John Newton, the agency’s Chief Knowledge Officer.

But PHE added that the costs to individual councils were considerable. Running the fluoridation plants costs councils on average 40p per person per year, it said – and that is after the initial consultation expenses and the cost of building the plant itself.

“Overall the benefits outweigh the costs… [but] there is no doubt that councils will want to consider the cost as one factor,” Prof Newton said. “These costs include the consultation, the capital to set up a plant and the revenue to run a plant.

“The capital costs have in the past been covered by central government but the revenue costs, which equate to around 40p per person per year, would need to be paid for by the public health grant of the local authority. This is a decision for each local authority to take.”

Birmingham City Council, which serves about one million constituents, told The Independent it spent £180,000 a year on the process. Dr Adrian Phillips, its Director of Public Health, said: “At less than 18p per person that’s less than the cost of a quarter of a tube of toothpaste.”

A mineral found naturally in water in varying amounts, fluoride is also present in certain foods, such as fish and tea. About 100 years ago, a link was discovered between higher fluoride levels in drinking water and lower tooth decay in the local population, leading to it being added to toothpastes to toughen people’s teeth.

It is estimated that worldwide, 380 million people live in artificially fluoridated areas – mainly in the US, Australia and Canada.

Sue Gregory, director of dental public health at PHE, said: “It is notable that the benefits of this public health measure appear to be greatest for children living in the most deprived areas of the country. This is significant for reducing the large differences we see in dental health between deprived and more affluent areas.”