International Programme on Chemical Safety

Inadequate or excess fluoride

Fluoride intake has both beneficial effects – in reducing the incidence of dental caries – and negative effects – in causing enamel and skeletal fluorosis following prolonged high exposure. The ranges of intakes producing these opposing effects are not far apart.

Public health actions are needed to provide sufficient fluoride intake in areas where this is lacking, so as to minimize tooth decay. This can be done through drinking water fluoridation, or, when this is not possible, through salt or milk fluoridation. Excessive fluoride intake usually occurs through the consumption of ground water naturally rich in fluoride, or crops that take up fluoride and are irrigated with this water. Such exposure may lead to crippling skeletal fluorosis, which is associated with osteosclerosis, calcification of tendons and ligaments and bone deformities.

While the global prevalence of dental and skeletal fluorosis is not entirely clear, it is estimated that excessive fluoride concentrations in drinking water have caused tens of millions of dental and skeletal fluorosis cases world-wide over a range of years. Although removal of excessive fluoride from drinking-water may be difficult and expensive, low-cost solutions that can be applied at a local level do exist. It is important that local authorities consider the causes of fluorosis carefully and choose the best and most appropriate means of dealing with excess fluoride exposure taking into account the local conditions and sensitivities.

Short information documents for decision makers

Tools for action

Norms and guidance values

WHO Burden of disease estimates