A major review has found ‘no definitive evidence' that water fluoridation produces either positive or negative health effects, however further studies on this topic are needed, the Health Research Board (HRB) has said.

Currently in Ireland, the public water supply is fluoridated. The practice is considered controversial by some, with anti-fluoridation campaigners arguing that adding substances to the water supply amounts to mass medication, which they insist is unethical.

However, some insist the practice is beneficial to health, so in response to this, the Department of Health asked the HRB to determine ‘what is the impact, positive or negative, on the systemic health (excluding dental health) of the population for those exposed to artificially fluoridated water?'

The HRB analysed two highly-regarded systematic reviews on this topic that were carried out in 2000 and 2007. It also analysed all additional research published in internationally peer-reviewed papers on this issue between 2006 and June 2014.

This research covered health issues such as cancer, cardiovascular disease, kidney disorders, thyroid disease, musculoskeletal effects and IQ.

"Having examined the research available, the HRB has found no definitive evidence that community water fluoridation is associated with positive or negative systemic health effects," commented HRB chief executive, Dr Graham Love.

However, he emphasised that ‘given the lack of peer-reviewed research and the inappropriate design of many studies to detect a causal relationship, further research would be required to provide definitive proof'.

This was backed up by the report's lead author, Dr Marie Sutton, who noted that research that specifically examines the link between community water fluoridation and health effects ‘is scarce'.

"Most of the studies reviewed are not of a suitable design to prove, or disprove, a link between fluoride consumption and negative health effects. Having examined the evidence, and given the lack of studies of appropriate design, further research would be required to establish any link between fluoride and negative health effects," she concluded.

The full HRB report can be viewed here