Alarming and very important news. Apparently, fluoride in water is neurotoxic, and lowers IQ. Children, unborn children, and heavy water drinkers may be among the most affected.

Other studies have previously found that IQs of breastfed babies are 10 points higher on average than IQs of newborns fed formula milk. Could neurotoxicity of fluoride in tap water, mixed with formula, be another factor in that?

Harvard Study Finds Fluoride Lowers IQ


[...]

After reviewing fluoride toxicological data, the NRC reported in 2006, "It's apparent that fluorides have the ability to interfere with the functions of the brain."

Choi's team writes, "Fluoride readily crosses the placenta. Fluoride exposure to the developing brain, which is much more susceptible to injury caused by toxicants than is the mature brain, may possibly lead to damage of a permanent nature."

Fluoride accumulates in the body. Even low doses are harmful to babies, the thyroid, kidney patients and heavy water-drinkers. There are even doubts about fluoridation's effectiveness. New York City Legislation is pending to stop fluoridation. Many communities have already stopped.

Infant formula when mixed with fluoridated water delivers 100-200 times more fluoride than breastmilk.
Update: arguments on Reddit point out that:
  • this is a press release merely being conveyed by Reuters, who disclaims responsibility for the content;
  • the study is flawed because it "relies almost exclusively on Chinese studies of fluorosis in high-fluoride areas", and "Asian drinking water is often extensively contaminated with fluoride concentrations above 4 mg/L". In contrast, "civil fluoridation is optimally .6-1.2 mg/L - the high levels in the study were 2.5 to 7 times that".
I'm not sure about you, but a safety margin of only a factor of 3.5 does not inspire me with confidence. If the margin is this low, it's easy to drink enough water to exceed the "safe" intake, and put you firmly in the fluoride intake levels of those populations where the study found children had lower IQs.

It's also easy to occasionally dump enough fluoride in the water to exceed the safe values. I've had water with an obvious severe overdose of fluoride in first world cities such as Miami and Vegas.

(I have a sensitivity to fluoride, which is why I use a non-fluoride toothpaste. When there's a lot of fluoride, I notice. In these cases, the water stank of it, and I felt the same adverse effects as from fluoride toothpaste.)