Is fluoride safe?

7: American IQ scores have risen alongside water fluoridation.

Between the 1940s and the 1990s, the average IQ scores of Americans improved 15 points. This took place at the same time that fluoridation expanded to serve millions more Americans. Claims made about fluoride and the developing brain are not based on sound science.

The Facts:
  • Claims that fluoride affects the brain appeared following an article, known as the “Harvard study”, which reviewed a variety of older studies that included IQ scores of children in China, Mongolia and Iran. The study did not test cause and effect or conduct research designed to explain a possible relationship between fluoride and IQ.
  • In many of the areas observed, the water had very high levels of natural fluoride — as much as 10 times higher than levels used to fluoridate public water systems in the U.S.
  • For more information, see Does Fluoride Lower IQ?

8. Comparing fluoridated and non-fluoridated communities shows that fluoride is really effective.

All over the world, comparisons show that people living in communities with fluoridated water have better oral health than those who don’t.

The Facts:
  • There is lots of proof that fluoridated water protects teeth. Since 2010, studies from Nevada. New York and Alaska have added to the overwhelming evidence that fluoridated water protects teeth from decay. Earlier studies from New Zealand and Great Britain also showed better oral health where there was fluoridation.
  • Products such as fluoride toothpaste, tablets and varnish are proven effective through tests called randomized clinical trials.
  • “Randomized” studies of fluoridation can’t be performed. That would require dividing a community into two groups: where one group of homes receive fluoridated water and the other does not. The danger of removing fluoride is that those households will, over time, have more tooth decay. Instead to setting up such a study, we rely on the entire body of evidence to demonstrate the effectiveness of fluoride.

9. Fluoridated water is safe for plants, animals, and fish.

Fluoride occurs naturally in streams, rivers, and lakes all over the world. The average fluoride level in ocean water is much higher than public water systems.

The Facts:
  • The amount of fluoride added to public water systems does not harm plants or animals. And research shows that even high levels of fluoride do not have a toxic effect on plants in places like ponds.
  • The average fluoride level in ocean water (1.4 milligrams per liter) is much higher than what is used to fluoridate public water systems. No reputable source has identified any negative effects on salmon or other fish that live in the ocean.