Dunedin fluoride-IQ study finds no ill-effect

Barry Taylor.
Barry Taylor.
A planned Dunedin study into whether fluoridated water reduces IQ has been shelved.

However, another University of Otago study looking at the same controversial question has been completed, its findings accepted for publication later this year in a prominent American public health journal.

Co-authored by public health dentistry specialist Dr Jonathan Broadbent, it found no negative effect on IQ.

Leader of the shelved study, child health researcher Prof Barry Taylor, said in an email the required data was too difficult to obtain.

''The fluoride data from the Ministry [of Health] has not [been] easy to interpret and match to the B4 School data - it has got to the stage where I do not think it is worth more effort at present.''

Prof Taylor had hoped to use information obtained from health and development checks performed on children before they start school, known as a B4 School Check.

Dr Broadbent's study drew on the Dunedin Multidisciplinary Health and Development Study, whose director, Prof Richie Poulton, worked alongside Dr Broadbent and other academics on the IQ study.

The ''world class'' Dunedin study was better suited for the analysis than before-school checks, he believed.

Overseas studies cited by anti-fluoride campaigners showing reduced IQ were ''rubbish'' because of design flaws, and had been widely discredited, he said.

The Dunedin study data was used in research that revealed marijuana adversely affected IQ. He believed some anti-fluoride campaigners supported decriminalising cannabis, which he found ''intriguing'' given its effects on the brain.

Visiting anti-fluoride campaigner Emeritus Prof Paul Connett, of New York, said independent scientists were concerned about the harm caused by fluoride.

That one study found no effects did not outweigh 37 overseas studies that demonstrated adverse effects, he said when contacted near Wellington.

He would examine them upon publication, but Dr Broadbent's study findings sounded ''rather convenient'', Prof Connett said.

A moratorium should be introduced to halt fluoridation of water supplies until the science was settled, he said.


If you want to split hairs

If you want to split hairs ,thats fine say .7-1PPM ,but same rules apply though


7-8 ppm?

7-8 ppm?

Just an adjustment

OK, to stop that nasty smell we should take the chlorine out and leave the natural fluoride as it is. Because the fluoride is in the water anyway and all that is done is an adjustment to the level to optimise the preventative tooth decay qualities.


The argument that fluoride is healthy just goes beyond what people all over the world experience themselves. Also the argument for fluoride in the drinking water does not answer the philosophical and moral questions about a substance which is a medication being put into all drinking water without the permission of the whole Dunedin population.

It is interesting to see people collecting water at the Speights tap. I do not know how many take water from that tap to avoid the fluoride and stinking chlorine smell of Dunedin water, but I would like to know.

The DCC does not have the medical qualifications or the moral right to add medication to all of the water supplying the city.

Can we get some support from the Greens on this please and maybe we would listen to you more?

After 70 years the science

After 70 years the science is well and truely settled. If it was as bad as the anti fluoride groups make it out to be it would have been banned years ago. The anti fluoride groups have tried to discredit it for years but they cannot come up with any reason why it is not safe to humans in the 7-8PPM range, that has been peer reviewed and published in a quality scientific publication. All they can do is make unsubstanuated claims that is causes everything including the black death, as a form of scaremongering.

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