CLAIMS that drinking water with added fluoride increases the risk of cancer have been rejected by an expert body.

The National Cancer Registry issued the reassurance in response to the use of the All-Ireland cancer atlas by some campaigning anti-fluoride groups.

The cancer atlas, drawn up by the Registry, maps cancer patterns in different areas of the country. The campaigners used it as part of the claim that some cancer rates could be linked to fluoridated drinking water.

The campaigners drew comparisons between the Republic, where fluoride is added to drinking water, and Northern Ireland where there is no such public health policy.

In response, the National Cancer Registry said the map has been “erroneously used by anti-fluoridation groups to suggest a link between water fluoridation and cancer”.

“We do not consider that water fluoridation is a plausible explanation for the patterns shown,” it said. It points to large studies carried out in Australia , Canada , New Zealand, Norway, the UK and the US to support this.

The atlas does not show a clear difference between Northern Ireland and the Republic of Ireland in patterns of the disease except for a small number of cancers.

There is a smooth gradient in cancer risk from the north-east to the south-west of Ireland, increasing right across the island.

There is no evidence of a change in this gradient at the Border between north and south except for prostate cancer and this is due to more men in the south going for PSA testing for the disease.

“Although the bulk of the population in the Republic of Ireland lives in cities and large towns, where the water is fluoridated, most of the area shown on the map is sparsely populated and without fluoridated water supplies, so water fluoridation cannot be suggested as an explanation for the patterns seen,” it added.

The Health Service Executive (HSE) said that over the past 50 years extensive research has been conducted into the health benefits of fluoride.

“The main benefit of fluoride is that it strengthens tooth enamel, the outer surface of the tooth, which provides protection against tooth decay”.

The Irish Expert Body on Fluorides and Health, which was established in 2004, monitors new and emerging issues on fluoride and its effects on health and related matters.

The Department of Health said it is satisfied, having studied current peer reviewed scientific evidence worldwide, that water fluoridation causes no ill effects to the health of adults or children.

“There are no plans to discontinue the policy of fluoridation of public water supplies, which continues to make an effective contribution to oral health in Ireland.”

Around 70pc of the water supplies in the Republic contain fluoride at levels which can provide protection for the teeth.

A condition called dental fluorosis can develop if a child’s teeth are exposed to too much fluoride when they are developing.

Mild dental fluorosis leads to very fine pearly white lines or flecking on the surface of the teeth while the severe form causes the tooth’s enamel to become pitted or discoloured. The advice is that flouride in toothpaste can be used when a child is two years of age.