Utah has become the first US state to ban the use of fluoride in its public water, following concerns raised by health secretary Robert F Kennedy that the mineral poses potential health risks.

Governor Spencer Cox signed the ban into law this week, which will go into effect on 7 May. Other states, including Florida and Ohio, are weighing similar legislation.

Fluoride has been added to US drinking water since 1945 to prevent cavities.

Utah's move to remove the mineral has been criticised by experts, who worry it will have consequences for oral health, especially for children.

The bill, signed by Cox on Thursday, prohibits communities from adding fluoride to their public water supplies.

The law does not mention any public health concerns related to the mineral, but Republican state lawmaker Stephanie Gricius - who introduced the bill in the state legislature - has argued that there is research suggesting fluoride could have possible cognitive effects in children.

Gricius has said that her bill would give citizens a choice whether they want to consume fluoride or not.

This concern over fluoride was previously raised by Kennedy, the US health secretary, who said in November that "the Trump White House will advise all US water systems to remove fluoride from public water".

He alleged the chemical found in toothpaste and regularly used by dentists "is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease".

Most public health experts have rejected these claims and alleged that Kennedy had cited data from studies conducted in countries with far higher levels of fluoride in their water systems than the US has.

The American Dental Association sharply criticised Utah for its decision, saying that it shows "wanton disregard for the oral health and well-being of their constituents".

"It is disheartening to see that a proven, public health policy, which exists for the greater good of an entire community's oral health, has been dismantled based on distorted pseudoscience," the association's president, Denver dentist Brett Kessler, said in a statement.

Many public health groups, including the American Academy of Pediatrics and the Centers for Disease Control and Prevention, have long supported adding small amounts of fluoride to drinking water.

The US Public Health Service reduced the amount of fluoride it recommended adding to water in 2015, but the federal government has encouraged states since the 1960s to add small amounts of the chemical to water to help prevent cavities and aid oral health.

Recent court rulings have led to the reduction of fluoride in US water, and some experts have questioned the continued need for it in water systems given its wide availability in toothpaste and other dental products.

Most of western Europe does not add fluoride to its water. In England, about one in 10 people has fluoridated drinking water, though a programme has since been introduced to fluoridate water for 1.6 million people in north-east England.

By contrast, around 63% of the US population have fluoridated water.

Experts who support putting fluoride in water says studies show that community water fluoridation prevents at least 25% of tooth decay in children and adults.

"The scientific weight of sound evidence around the benefit of community water fluoridation is clear and compelling," the American Dental Association said in October of last year.

Prof Avijit Banerjee, chair of cariology and operative dentistry at King's College London, previously told the BBC that "the potential harmful effects of fluoride cited have not been associated with the very low levels of fluoride used in water fluoridation programmes" (BBC)

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