The truth about water fluoridation

Fluoridation of water is a public health intervention that was started last century. Back then, scientists noticed that people who drank water naturally containing fluoride had 50 percent fewer cavities. Today, fluoridation is a widespread practice around the world. Local governments test water sources and adjust the fluoride amount to a specific range.  Fluoridation has been recognized by the Centers for Disease Control and Prevention as one of the greatest public health achievements of the 20th century.

However, the practice is not without its critics. Opponents claim that it does not prevent cavities and can be harmful to children's health. "The current consensus is that fluoride ingestion does not reduce tooth decay," said Carol Kopf, media director for the Fluoride Action Network.

"Promoters of fluoridation frequently exaggerate the benefits of fluoridation," said Paul Connett, PhD, in an email, a professor of chemistry at St. Lawrence University in Canton, N.Y., and a known leader in the anti-fluoride community.

Yet in looking at 70 years of data, it's hard to understand this stance. "In my opinion, water fluoridation is critically important to help prevent one of the most common and chronic diseases – tooth decay," said Rocio B. Quinonez, DMD, an associate professor at the Department of Pediatric Dentistry and Pediatrics at UNC at Chapel Hill. The majority of data seems to agree with her. Fluoride's ability to prevent cavities is well-documented. Fluoridation's benefits are touted by the vast majority of dentists, physicians and scientists as well as all major health organizations around the globe.

Concerned groups have also claimed that public fluoridation of water causes harmful levels of fluoride, especially in children. Specifically, they focus on possible brain damage, leading to lower IQ. In his email, Dr. Connett referenced a review of foreign fluoridation studies done at Harvard, which seem to show IQ loss in areas where fluoride concentrations were high. Since then, the study has been analyzed, shown to have multiple profound flaws, and debunked as can be seen here. Its authors admitted, "[the studies] reviewed had deficiencies, in some cases rather serious, which limit the conclusions that can be drawn."

Earlier this year, a large study from New Zealand found fluoride did not affect IQ levels. It followed more than 1,000 people who received fluoride supplements over (an impressive) 38 years. The researchers measured IQ levels of people who received the fluoride versus those who did not and found both groups had the same average IQ. This study joins a huge collection of hundreds of studies attesting to fluoride's safety.

The only health problem scientifically proven to be caused by excessive fluoride is a cosmetic condition known as fluorosis. Fluorosis causes staining of teeth in children under eight and is most often mild and reversible. Fluorosis can be prevented by monitoring the total amount of fluoride a child consumes. Total consumed fluoride includes what the child receives from the water supply, from fluoridated toothpaste, and from periodic fluoride treatments at the dentist's office.

In Philly, water fluoride levels are kept around 0.7 parts per million: a very low, but effective level. However, to get an idea of how much total fluoride your child is getting, talk to your dentist or pediatrician.  All together, the levels local children are exposed to are very safe and will help keep their teeth healthy and strong.

The American Academy of Pediatrics and American Dental Association recommend the following for the safe prevention of cavities in children:

Have a question for the Healthy Kids panel? Ask it here. Read more from the Healthy Kids blog »