The most common argument against fluoridation is pretty simple: In excessive doses, fluoride causes health problems -- so why risk it? Fluoride can cause discoloration or corrosion of teeth (dental fluorosis) and it can possibly weaken bones (skeletal fluorosis). In the 1990s, the U.S. Public Health Service noted an increase in dental fluorosis in fluoridated areas since the 1940s, when water fluoridation began. But the evidence is considered inconclusive because lots of products (like toothpaste, mouthwash and dietary supplements) now contain fluoride that didn't 60 years ago. So it's hard to know where the fluoride overdose is coming from -- the water or the toothpaste.
But in March 2006, the National Research Council declared that the U.S. EPA is allowing levels of fluoride in drinking water that could damage children's teeth. At water-fluoride levels at or above 4 ppm (or 4 mg/L), there is evidence to suggest that consumption could increase the risk of serious fluorosis [source: Prevention].
The National Academy of Sciences estimates that as of 1992, more than 200,000 people in the U.S. were drinking water with fluoride levels above 4 ppm. The NAS states that levels above 2 ppm can cause cosmetic dental issues like white spots on teeth, a very mild form of dental fluorosis [source: NAS]. This may seem like a cut-and-dry case for discontinuing water fluoridation, but the ADA points out that while these levels surpass the optimal fluoridation level for dental benefits, they're still safe -- 4 ppm is what the EPA has set as the maximum amount of naturally occurring fluoride. Above that level, cities are supposed to remove fluoride before the water is considered safe.
It's proven that ingesting high levels of fluoride can cause health problems, and the EPA has been regulating fluoride as a drinking-water contaminant for decades. But from there, the case gets hazy, since so many experts set forth the case that adding small amounts of fluoride to the public water supply can safely decrease the incidence of dental problems. Organizations like the U.S. Public Health Service, the Centers for Disease Control and Prevention, the National Cancer Institute, the International Dental Federation and the World Health Organization all believe that water fluoridation is a health benefit. In 1999, the CDC actually named water fluoridation on the top 10 list of 20th century health achievements.
The debate about the risks and benefits of fluoride will continue until not only the scientific community but also the general public can agree on the matter. The biggest argument against fluoride is that it damages children's teeth, and there's some evidence to that effect.
Many countries, including the U.S., Canada, Ireland, Australia and New Zealand, still fluoridate drinking water (and about 10 percent of the British population drinks fluoridated water). Germany, France, Belgium and Switzerland do not -- although some of those countries do fluoridate their table salt.
Most organizations and countries agree, however, that infants shouldn't ingest extra fluoride. In November 2006, the American Dental Association recommended against giving fluoride-enhanced products to children less than one year old. Studies have shown that infants who drink fluoridated water are at significant risk for dental fluorosis. For decades, parents have been warned to supervise young children brushing with fluoride toothpaste so they don't swallow a mouthful of the stuff.
Clearly, there are risks associated with fluoride consumption. What people can't seem to agree on is whether fluoridated water carries risks for adults and whether those risks outweigh the possible benefits to oral health.
To learn more about fluoride, look over the links below.
Related HowStuffWorks Articles
More Great Links
- Bender, David A. "Bender's Dictionary of Nutrition and Food Technology (8th Edition)." Woodhead Publishing.
- Fluoride. National Institute of Dental and Craniofacial Research. http://www.nidcr.nih.gov/HealthInformation/DiseasesAndConditions/Fluoride/
- Fluoride in Drinking Water: A Scientific Review of EPA's Standards. The National Academy of Science. http://dels.nas.edu/dels/rpt_briefs/fluoride_brief_final.pdf
- Fluoride Toxicity. eMedicine. http://www.emedicine.com/emerg/topic181.htm
- Gower, Timothy. The Danger in Your Water. Prevention.com. http://www.prevention.com/cda/article/the-danger-in-your-water/319972e50d803110VgnVCM10000013281eac____/health/healthy.lifestyle/wellness
- "National Research Council Issues Report on EPA Standards for Fluoride in Drinking Water." American Dental Association. http://www.ada.org/prof/resources/topics/science_fluoride_water.asp
- New Fluoride Warning for Infants. Mothering Magazine. November 2006. http://www.mothering.com/sections/news_bulletins/november2006.html#fluoride
- Oral Health. Rhode Island Department of Health. http://www.health.ri.gov/disease/primarycare/oralhealth/prevention-fluoridation-map.php
- Prevention Magazine Looks at Water Fluoridation. ADA.org. http://www.ada.org/prof/resources/topics/science_fluoridation_prevention.asp
- Review of Fluoride: Benefits and Risks. Public health Service. http://health.gov/environment/ReviewofFluoride/
- "Sodium Fluoride (Systemic).Drugs.com. http://www.drugs.com/cons/sodium-fluoride.html
- Water Fluoridation: Questions and Answers. Ireland Dental Health Foundation. http://www.dentalhealth.ie/information/index.tmpl?secid=20020822160750&subid=20020828150540
- Ziegelbecker, Rudolf. International Society for Fluoride Research. http://www.fluoride-journal.com/98-31-3/313-171.htm