Fluoride Is Toxic to Developing Brains, New Studies Find

 By Bruce Lanphear, Christine Till and Linda S. Birnbaum

The debate on the fluoridation of drinking water — one of the most polarized, long-running, and high-decibel controversies in public health — has been reignited as new studies find that fluoride is toxic to the developing brain.

Last week, the U.S. National Toxicology Program released a systematic review of all published studies evaluating the potential neurotoxicity of fluoride; the benefits of fluoride with respect to reducing tooth decay were not addressed. A committee of the National Academy of Science, Medicine, and Engineering will review it this fall. This comprehensive report scrutinized hundreds of human and animal studies on the impact of fluoride on brain and cognitive function. Most, but not all, of the high-quality studies evaluated fluoride concentrations that were about twice the level added to drinking water or higher. However, when considering all the evidence, their conclusion was “fluoride is presumed to be a cognitive developmental hazard to humans.”

The National Toxicology Program’s conclusion was strengthened by a synthesis of high-quality studies showing that children who were exposed to higher amounts of fluoride during early brain development scored about 3 to 7 points lower on their IQ tests.

Their conclusion is consequential as about 75% of Americans on community water systems have fluoride in their tap water. Water is the main source of fluoride for people who live in communities with water fluoridation.

When do we know enough to revise long-held beliefs? We are reminded of the discovery of neurotoxic effects of lead that led to the successful banning of lead in gasoline and paint. Despite early warnings of lead toxicity, regulatory actions to reduce childhood lead exposures were not taken until decades of research had elapsed and millions more children were poisoned.

We know that the developing brain is exquisitely sensitive to minute concentrations of lead and other toxic chemicals. Moreover, toxic chemicals’ irreversible effects on children’s rapidly growing brains emphasize the need for prevention.

Failing to act on accumulated evidence raises deep and unsettling questions. Why are beliefs about the safety of fluoride so intransigent in the face of consistent evidence to the contrary?..........................................