Is fluoride in drinking water safe?

Question

"The recommended fluoride concentration in drinking water is 0.7 milligrams of fluoride per liter of water, which is about equal to 3 drops in a 55-gallon barrel, according to the CDC. 

In 2015, officials lowered the recommendation for drinking water fluoride levels to address fluorosis, a condition that can cause discoloration on teeth."

Answer 1

Regarding fluoride's effectiveness at strengthening enamel and preventing tooth decay, the article cites reliable sources like the World Health Organization. The hyperlink it provides redirects to a page that specifically states fluoride's use in tooth disease prevention.

https://www.who.int/news-room/fact-sheets/detail/sugars-and-dental-caries#:~:text=Severe%20dental%20caries%20can%20impair%20quality%20of,chronic%20systemic%20infection%20or%20adverse%20growth%20patterns.&text=Early%20stages%20are%20often%20without%20symptoms%2C%20but,pain%2C%20infections%20and%20abscesses%2C%20or%20even%20sepsis.

The article's mention the concern with fluoride is also correct. The article states that the NIH report states that " 'with moderate confidence' that there is a link between higher levels of fluoride exposure and lower IQ in kids", when it is double the US standard. The NIH report states that "there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ", and the "higher levels of fluoride" mentioned in this article is “ higher than 1.5 mg fluoride/L of drinking water”, which is double the US fluoride level. The NIH report's ground for determining higher levels of fluoride is that studies in non-US countires find drinking  higher than 1.5 mg fluoride/L has some effect on IQ.

https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/fluoride

Answer 2

Fluoride is a mineral that strengthens teeth and reduces cavities by repairing and preventing damage caused by bacteria that produce acid, which can dissolve tooth minerals and lead to tooth loss, according to the U.S. Centers for Disease Control and Prevention. One of the biggest points of controversy about fluoride arose from a 1990 study by the US National Toxicology Program, which found "equivocal" evidence showing that drinking fluoridated water caused increased incidence of bone cancer in male rats. However, it should be noted that this phenomenon was not observed in female rats or in mice. Research by various other health organizations have also concluded that as long as fluoride levels in drinking water are within optimal range (0.7 milligrams per liter of water), the chemical is not considered a cancer risk.