Declan Waugh,
Environmental Auditor and Risk Management Consultant,
Bandon, Co Cork., Ireland

The Health Research Board (HRB) in its recent review said that it found no definite evidence that community water fluoridation has negative health effects (‘No conclusive proof’ of negative effects’, IMT, June 12, 2015).

Yet remarkably, and extraordinarily, the review did not in any way access the exposure of the Irish population to fluoride; including the contribution of water fluoridation, food or beverage consumption, medicines or occupational exposures to fluoride from certain industries.

From a risk-management perspective there is only one accurate way to access exposure and therefore risk, and that is to use established biomarkers of fluoride exposure by measuring the fluoride content in human blood, urine or bone, as well as measuring the fluoride content in commonly consumed beverages, foods as prepared with fluoridated water and to determine the exposure of the population to fluoride-releasing medications that are commonly prescribed in Ireland. Not one of these tasks were undertaken by the HRB.

In addition, the review, while examining the literature on fluoride and neurological disease, somehow managed to exclude the recently published study in the journal Environmental Health titled ‘Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association’ (Environmental Health 2015, 14:17doi:10.1186/s12940-015-0003-1).

This study empirically demonstrated an association between more widespread exposure to fluoridated water and increased ADHD prevalence in US children and adolescents, even after controlling for socioeconomic status, and was published in February this year, the same week that Peckham and associates published their study on water fluoridation and thyroid disorders in the UK. The latter study was included in the HRB review, but the former was not. Why not?

Overall, the Board’s desk-based review entirely excluded the published literature that had found that many common medications could cause fluoride intoxication. This is a matter of significant public health concern, as the European Food Safety Authority (EFSA) noted that medications can contribute to more than 75 per cent of the daily fluoride intake for infants alone.

More than 60 published studies internationally have also found excessive concentrations of fluoride in tea, which is the most widely consumed beverage in Ireland. Did the HRB measure the fluoride content in tea products sold in Ireland?

We know now it did not, in fact, and tea as a source of fluoride was only noted in its report as it was previously documented by me in correspondence to the Department of Health’s Chief Medical Officer among others, a fact the Board documented in its review. Despite this, the review could only conclude that “tea leaves contain proportionally higher levels of fluoride than CWF water that is used to make it”. This statement does not reflect the full facts. Tea contains substantially higher concentrations of fluoride than CWF.

In 2006, the National Research Council of the United States (NRC) stated that in the UK consumers can ingest 9mg per day of fluoride from tea drinking alone and that making tea with fluoridated water contributes to excess fluoride intake and the risk of chronic disease.

Furthermore the US NRC (2006) reported that consumption of just half a cup of brewed tea with an average fluoride concentration of 3.3 mg/L would equal the total background intake of fluoride from all food sources . Moreover, in 2008, the Department of Public Health in Taiwan conducted a risk assessment on fluoride exposure from tea drinking measuring the fluoride content in more than 50 specimens of tea using de-ionised water. The concentration of fluoride in the majority of tea samples was found to exceed 4 mg/l.

The authors found that elderly persons, who generally consumed greater quantities of tea, would exceed the acceptable daily intake (ADI) for fluoride from tea drinking and concluded that caution should be undertaken in considering fluoridation of water in Taiwan in order to avoid side-effects. Drinking water is not fluoridated in Taiwan, but more importantly, per capita consumption of tea in Ireland is significantly higher than Taiwan.

Ireland has the highest per capita consumption of tea in the world, 17 per cent higher than the UK, 14-fold higher than the US and over 40-fold higher than countries such as Spain, Belgium or Portugal. Tea is the most frequently consumed beverage in Ireland, consumed by 91 per cent of adults aged 18 to 64 years of age, with the average person consuming four cups of tea every day.

The EFSA has established that the upper tolerable intake for fluoride to prevent chronic disease for a healthy adult is 7mg/day.

Furthermore, the EFSA estimated that drinking just two cups of tea per day, combined with an average consumption of fluoridated drinking water and use of fluoridated tap water in the preparation of food, but excluding all other sources (including solid foods, toothpaste and dental products), would provide a daily dietary intake of 6mg per day.

One must assume that the HRB and Food Safety Authority would also be aware that China recently banned the importation of tea from Kenya, due to toxic levels of fluoride found in its tea.

So what does this say about the HRB review? Clearly, the HRB found no definite evidence that water fluoridation was causing harm, because, as with every other review undertaken in this country, they failed to measure the fluoride exposure of the population.

The requirement for a comprehensive risk assessment addressing ‘any risk’ is a prerequisite to the application of the precautionary approach. On the basis of a vast amount of published studies and risk assessments of fluoride intake from tea and certain medications, there is absolutely no doubt that the Irish population is chronically exposed to fluoride, or that water fluoridation is further contributing to this overexposure.

The HRB and the Department of Health have a legal responsibility to determine what the true exposure to fluoride is among the Irish population from food, beverages and medications; only when they have done this can they determine if the risk of water fluoridation is acceptable.

In the absence of these studies and their failure to understand that it is total fluoride intake that is important when assessing the risk of water fluoridation, I find their claims difficult to accept.

The HRB’s review, by excluding published literature showing that fluoride intake similar to what the Irish populace may be exposed to from tea and other sources has been found to be associated with a staggering amount of chronic diseases, only allows water fluoridation to continue to endanger the health and well-being of Irish citizens.