Public Health South officials have criticised a Dunedin-based anti-fluoride lobby group for “misleading and untrue” claims about the Blueskin Bay water supply.

Fluoride Action Network Dunedin representative Olive McRae warned mothers in the Blueskin Bay area not to use the area’s new fluoridated tap water to mix infant formula.

“This is due to medication of the new water supply with silico-fluoride, a dangerous neurotoxin. Babies are at extreme risk of fluoride poisoning when they are exposed to fluoridated tap water,” it read.

The claims were contained in a letter sent by Ms McRae to the Blueskin News and published on its website under the heading “opinion”, followed by a response by Public Health South medical officer of health John Holmes.

In his response, released to the Otago Daily Times last week, Dr Holmes criticised the Fan claims as “misleading and untrue”.

He said powdered infant formula available in New Zealand contained “negligible” amounts of fluoride, with the major source of fluoride in any formula coming from the fluoridated tap water it was mixed with.

There was no evidence fluoridated water used to reconstitute the formula has any harmful effects in areas where fluoride concentration was no more than one milligram per litre (mg/L), the guideline recommended by the Ministry of Health.

Dunedin’s drinking water contained fluoride concentrations of 0.85mg/L.

Ministry of Health chief dental officer Robin Whyman said an update of some guidelines around the discretionary use of fluoride was under way, although it was “unlikely” to result in a change to advice about infant formula.

“The Ministry’s current advice is that breast is best for babies, but that infant formula is able to be reconstituted with fluoridated water.”

Ms McRae declined to comment when contacted, but Fan New Zealand national co-ordinator Mark Atkin, of Wellington, said Ministry guidelines for infant formula were “propaganda” that ignored international research.