Water fluoridation: Control of fluoridation to be taken off councils, given to Dr Ashley Bloomfield

Councils will no longer have control over New Zealand's water fluoridation, with Director-General of Health Dr Ashley Bloomfield set to take the reins.

Associate Minister of Health Dr Ayesha Verrall announced on Thursday a proposed amendment to the Health (Fluoridation of Drinking Water) Amendment Bill, a draft legislation from the former National Government that intended to shift fluoridation power from local authorities to district health boards (DHBs). The Bill was introduced into the House in 2016. 

Water fluoridation is the controlled adjustment of fluoride to a public water supply solely to reduce incidents of tooth decay. Fluoridated water contains the chemical compound at a level that is effective for preventing cavities, which can either occur naturally or by adding fluoride.

The bill will now be amended so that power is instead given to Dr Bloomfield, the country's leading public health official.

The proposed change, to be made by a Supplementary Order Paper, will simplify decision-making around fluoridation, Dr Verrall said on Thursday. 

"The Government is proposing an amendment to see that decision-making sits with the Director-General of Health," she said.

“The proposed change… simplifies the decision making and means we are taking a nationally consistent approach that’s based on evidence."

Dr Verrall noted that tooth decay is one of the leading causes of preventable hospitalisations for children, with around 6500 children under the age of nine admitted to hospital for tooth decay and associated infections in 2019. 

Fluoride, a chemical, is added to more than half of the country's drinking water in minuscule amounts to support healthy teeth - however, only around 2.3 million New Zealanders currently have access to fluoridated drinking water.

And although fluoridation is a proven public health measure that can make a big difference to children's wellbeing, the current level of fluoride found naturally in New Zealand's water supplies is not enough to prevent tooth decay.

"'Topping up' fluoride levels allows the well-established health benefits to reach all New Zealanders, especially our children, Māori and Pacific populations and people in our poorer communities," Dr Verrall continued. 

"Given that fluoridating our drinking water is widely recognised as the single-most important initiative to improve oral health, I expect this Bill to pass this year."

The amendment will likely generate backlash, with fluoridation proving a controversial topic. In the past, councils have halted the process in response to intense pressure from anti-fluoride activists. 

As fluoride can be toxic in large quantities, anti-fluoridation movements argue the public should have a say in regards to the chemicals they are ingesting. Yet according to health officials, a person would need to consume thousands of glasses of fluoridated water in a single sitting before they were anywhere near a lethal dose. 

Dr Verrall added that local authorities are responsible for the capital and operational costs of fluoridation, and funding will be made available to support councils with work on fluoridation-related infrastructure.

The statement noted the World Health Organization's recommendation to boost fluoride to optimum levels through the fluoridation of public water supplies. 

In 2016, the Ministry commissioned an independent report, Review of the Benefits and Costs of Community Water Fluoridation in New Zealand, which suggested there is a 40 percent lower lifetime incidence of tooth decay among children and adolescents in areas with fluoridated drinking water.

The findings also suggest communities with access to fluoridated drinking water see a 48 percent reduction in hospital admissions for the treatment of tooth decay among children aged 0-4 years; a 21 percent reduction in tooth decay among adults aged 18–44 years; and a 30 percent reduction in tooth decay among adults aged 45 years and over.