I feel the need to science a bit. This is based on my layman’s understanding of the science. I may not have a perfect grasp of this, but the basics should be solid. Bear with me.
There are people who don’t want fluoride in their bodies. I am not here to judge or advocate for those who see fluoride as an essential nutrient or try and change the minds of those concerned by the idea of ingesting fluoride. I’m posting to provide helpful advice to those who wish to keep fluoride away from their body, and further information for anyone interested.
Here is the former:
Don’t drink water that has come in contact with soil or rock since it last exited the vaporous state to avoid imbibing fluoride with your water.
This is the latter:
Fresh water, which has come from a land-based source, such as a lake, river, spring, or well/bore, contains fluoride. The concentrations vary wildly, as different places have varying amounts of it present in rock and soil, but it’s almost entirely ubiquitous.
It’s actually quite a hassle to find fluoride-free, potable, standing or running water. It almost never happens without human intervention, in the form of rainwater collection or condenser technology. It amazes me how few are aware of this in the fluoride-sceptical demographic, especially in this country, where fresh water kaitiakitanga is to the fore.
In the wild, in areas with high levels of fluorine in the soil due to volcanic activity and the like, you also find clinically significant or problematic concentrations in the water table. Hydrothermal activity can place fluorine in rock and soil, and sedentary rock formed from volcanic rock can be fluorine-rich. This dissolves in water as fluoride, which our bodies use to help mineralise our teeth. When our teeth demineralise we are prone to tooth decay, and the health issues that follow.
The upper limit of the safety guidelines, according to the science, is more than three times the natural concentrations found in most lakes and rivers. It takes higher concentrations again before adverse in utero developmental outcomes (lower IQ) occur, and these apparently occur at very specific stages of pregnancy. Possibly this has been researched enough, but in most locations isn’t a risk mothers face, and let’s face it, science has always tended to neglect women. For the sake of mothers and infants in places where natural fluoride levels are very high I think more work is probably wanted, and public awareness is unforgivably low.
Fluorosis, the detrimental effect of too much fluoride, can affect teeth and/or bones. Dental fluorosis can be seen in the photo, which is used under the Creative Commons licence and sourced from Wikipedia. It shows up as white striations in the enamel. It occurs after overexposure in childhood, between the ages of one and four years of age, and apparently is a purely aesthetic flaw. It would be unusual here, but more common than the in utero neurodevelopmental issues or bone fluorosis. Aotearoa is more prone to swing the other way, with very real tooth decay issues. Bone fluorosis I know nothing about, aside from the fact that it can weaken bones, but isn’t tied to cancer.
In the rare populations drinking from water supplies with excessive concentrations, defluoridation is the norm and recommended. This can be done by percolation through certain particulates, amongst other things, which is possibly why all but the one* supply downstream of volcanic areas in Aotearoa have levels well below those found to be safe. Speculation: The compound, calcium phosphate (Ca3(PO4)2), often used in this process, can occur naturally in rock too. In soil with a pH greater than six, calcium and soluble phosphate will form the same, and around our country phosphate fertilisers are dumped on farmland in stupefying amounts. My reasoning here may be flawed. Comments from anyone with knowledge around this are most welcome. This is the furthest extent of my knowledge on the subject, and I love learning.
* Apparently only the water table south of Te Ika a Māui’s volcanic plateau has clinically significant concentrations, so for Kiwis it might be possible to find cases of fluorosis there, but it would probably take more than the naturally occurring fluoride in the water to bring it about, even there.
