The report linked fluoride levels of 1.5 mg/L — about twice the level recommended by federal health officials — with lower IQ in children.

So, critically, none of these human studies tell us anything about how fluoride changes the brain at a biological level. Even studies in lab animals and cells did not identify how fluoride might affect learning, memory, or intelligence.

 IQ scores also only capture an incomplete picture of early childhood brain development and are tangled up in a number of socioeconomic, racial, and culturalfactors beyond how much fluoride someone is exposed to.

If you’re concerned about your family’s fluoride exposure, you can check your tap water’s fluoride levels on the CDC’s My Water’s Fluoride page. If you happen to live somewhere with levels above around 1.5 mg/L, your tap water crosses the threshold of neurodevelopmental concern. No need to switch to bottled water, though; home water purifiers can filter fluoride out completely.

To make sure you don’t throw out the oral health benefits of fluoride with the bathwater, keep using fluoride toothpaste for those over the age of 2 (just don’t swallow it). 

And if you’re still fluoride-skeptical, you can order some hydroxyapatite toothpaste— which has similar cavity-preventive benefits — from Europe or Canada, where it’s been approved and endorsed by dental associations.

https://link.vox.com/view/608c6bdb7e3ba002de943130ls8ap.hb6/3c0b43a3