Fluoridation of water supply is considered by the World Health Organisation as one of the top public health successes of the 20th century but some say you can have too much of a good thing.
The US Department of Health and Human Service is now recommending fluoride levels be lowered to no more than 0.7 milligrams per litre (ppm).
“Making this adjustment now will promote public health, improve oral health and reduce rates of fluorosis,” spokesman Howard Koh said.
A government study shows up to a third of American children are affected by fluorosis – a spotting and streaking of teeth associated with too much fluoride. Previously the recommended fluoride level was 0.7 – 1.2 milligrams per litre of water but the new recommendation is 0.7.
The Fluoride Action Network New Zealand said the study shows officials have been wrong for the last 50 years.
“If they’ve been wrong for the last 50 years why would people simply believe them today. People need to do their own research,” spokeswoman Mary Byrne said.
“There’s lots and lots of studies associating fluoride with serious adverse health affects.”
But the Ministry of Health said fluoridation of water prevents up to 270,000 decayed, missing and filled teeth every year.
Just over half the population has access to fluoridated tap water with levels of between 0.7 and 1 milligram per litre. The level depends on local councils and 26 out of 69 in New Zealand add fluoride to drinking water. Hastings and Kapiti dropped their level to 0.7ppm last year, against the advice of the ministry, while Whakatane and New Plymouth have resolved to review fluoridation.
Dentists maintain that NZ’s system is working as our fluorosis levels are low and mild while in America there can be a more is better attitude.
“People tend to go and use supplements and mouth washes which are not used that much in New Zealand,” said NZDA president John Bell.
Byrne believes New Zealand’s Health Ministry now has no choice but to also recommend councils drop their maximum fluoride levels to 0.7ppm.
“Councils are adding a hazardous waste to drinking water,” she said.
The Ministry of Health said it takes developments into consideration and it is committed to balancing the benefits of fluoridation against any adverse health effects.