The most comprehensive scientific study of fluoride in food, beverages and tap water ever undertaken in Ireland concludes there are no health concerns for children and adults from exposure to the mineral.

Fluoride is added to public drinking water to help reduce tooth decay, especially in young people.

The Food Safety Authority of Ireland (FSAI) report produced by its independent scientific committee evaluates consumption of fluoride from the Irish diet by analysing 216 samples across 18 categories of the most commonly-consumed foods and beverages, including 10 varieties of tea, over the 2014 to 2016 period.

The overall aim of the study was to establish the typical intake of fluoride that the Irish population gets from food and drinks.

It also factors in absorption of fluoride in cooking as happens for example when pasta, rice and vegetables are cooked in fluoridated water.

Human exposure to fluoride can vary considerably, depending on the levels of fluoride found in drinking water and on individual dietary and oral hygiene habits. Virtually all foodstuffs contain at least some traces of fluoride, and some are known to contain relatively high fluoride concentrations; notably tea and seafood.

Estimates of fluoride intake in the study do not include fluoride contributions from non-dietary sources, particularly through swallowing fluoridated toothpaste, which can make a significant contribution in young children, but much less so in older children and adults.

Combining fluoride from toothpaste and other dietary intakes would not result in excessive consumption by adults or children, the report finds, though “misuse of toothpaste may result in higher intakes of fluoride in a small proportion of young children”.

The report estimates the level of exposure of different segments of the population and from that result then examine if the levels were considered safe or posed any risk to health.

There is “no consistent evidence of an association” between consumption of fluoridated water and cancer, the FSAI report notes.

While fluoride is not essential for human growth and development, excess intake can cause Fluorosis affecting teeth and bone density.

The report concludes there is “no appreciable risk of moderate dental fluorosis in children aged 1 to 8 years of age arising from fluoride intake from foods and beverages”.

Black tea, which can contain naturally high levels of fluoride, was found to contain by far the highest fluoride concentrations though within set upper limits. It was “the most important dietary contributor to fluoride intake in adults, and to a much lesser degree in children and preschool children” – adding milk to tea did not affect fluoride level consumed.

With the exception of fish and fishery products and one nut sample, all other foods showed fluoride concentrations below 1 milligram/kilogram; which is acceptable from a public health perspective.

The average water fluoride concentration for fluoridated public water supplies in Ireland was 0.65 mg/Litre.

Since 2007, the level of fluoride in public water supplies in the Republic of Ireland has been set at between 0.6 and 0.8 mg/L.

Fluoride exposures in preschool children (1 to 4 years of age) and children (5 to 12 years of age) were much lower than in adults, largely due to much higher consumption of black tea in adults.

“Adults are predominantly exposed to fluoride via consumption of black tea, which constitutes 76 per cent of their total fluoride exposure, with tap water contributing 12 per cent. Tap water was the main contributor to fluoride intake in children (49 per cent in preschool children aged 1-4 years, 33 per cent in children aged 5-12 years), while tea was a significant contributor (29 per cent) in children aged 5-12 years.”

FSAI chief executive Dr Pamela Byrne said the report is based on the most recent food consumption patterns in Ireland and fluoride concentration data in food and beverages.

“This report serves to provide independent and impartial information on the exposure to fluoride through the Irish diet. It is an important piece of research which also takes into account naturally-occurring levels of fluoride in food and beverages we consume in our diets,” she said.

The FSAI’s scientific committee includes some of the best scientific experts in their field in Ireland, who “bring independent, impartial and expert scientific acumen to inform and ensure that our work is based on the best science available at a given time”.

“This study reaffirms the FSAI’s and its scientific committee’s view that exposure to fluoride from the diet for all population groups in Ireland is not of concern,” she added.