The US Food and Drug Administration (USFDA) has suggested a revision to the acceptable level of fluoride in bottled water.

If approved, the limit would be reduced to 0.7mg per litre, bringing it in line with the recommended level set by the US Public Health Service (PHS) for community water companies that add fluoride to improve dental health.

In 2015, the FDA suggested that the bottled water industry should also follow these recommendations, and several manufacturers have already taken preparatory steps as a result.

The latest proposal will be applicable to both bottled water that is produced in the US, as well as those imported into the country.

“Too much fluoride over a long time when teeth are forming under the gums can cause changes in the appearance of tooth enamel.”

The FDA’s Center for Food Safety and Applied Nutrition director Susan Mayne said: “Fluoride provides an important public health benefit by helping to reduce cavities and tooth decay. But too much fluoride over a long time when teeth are forming under the gums can cause changes in the appearance of tooth enamel, called dental fluorosis.

“Striking the right balance is especially important for children under the age of 8 as their permanent teeth are still forming. It’s the FDA’s responsibility to ensure that if fluoride is added to bottled water, it is added at appropriate levels so that consumers receive its important health benefit while also being protected from potential adverse effects.

The FDA further noted that the proposed rule will not be applicable for bottled water where fluoride is not added by the manufacturer.

Mayne further added that the recommendation: “provides an optimal balance between the prevention of dental caries and the risk of dental fluorosis.”

The FDA will allow a 60-day comment period to receive feedback from the public, the industry and other stakeholders.