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How much fluoride is too much?

Yep, lots of toothpaste contains fluoride, but who knew that juice does, too?
Yep, lots of toothpaste contains fluoride, but who knew that juice does, too?
iStockphoto/Thinkstock

In the early part of the 20th century, researchers concluded that adding up to 1.0 parts part million (ppm) of fluoride to drinking water had the desired effect of inhibiting tooth decay while minimizing undesirable effects, such as dental fluorosis (staining and pitting of tooth enamel). In 1945, the city of Grand Rapids, Michigan became the first city in the world to fluoridate its drinking water and to study the effects of drinking water fluoridation on tooth decay. After studying Grand Rapids school children for 11 years, the National Institute for Dental Research announced that rates of tooth decay had decreased by more than 60 percent [source: NIDCR]. Over the next several decades, more and more communities in the U.S. began adding fluoride to their drinking water. Today, drinking water fluoridation is a common, though not universal practice.

Opponents of fluoridation have long argued that the policy subjects US citizens to unknown health risks and smacks of nothing less than government mandated medication. They point out that ingesting excess fluoride over a long period of time can cause increased likelihood of bone fractures and bone pain. Furthermore, children 8 years old and younger who are exposed to fluoride are at increased risk for developing dental fluorosis [source: CDC]. On the other hand, fluoridation has inarguably lowered rates of tooth decay, and the Centers for Disease Control (CDC) cite water fluoridation as one of the 10 great public health achievements of the 20th century [source: CDC].

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With everyone from the Environmental Protection Agency (EPA) to the American Dental Association lauding the benefits of fluoride, it's no surprise that manufacturers began to add fluoride to consumer products besides drinking water. Today, fluoride can be found in many products including toothpaste, mouthwash, juice, soda, dietary supplements and even certain pesticides. With all these additional sources of fluoride available to us, the time has come to ask how much fluoride is too much. Get the facts on fluoride on the next page.

Children are most at risk from excessive amounts of fluoride.
Children are most at risk from excessive amounts of fluoride.
John Moore/News/Getty Images

In January 2011, the Department of Health and Human Services (HHS) and the EPA announced that they were proposing decreasing the recommended level from .7 - 1.2 milligrams per liter (mg/L) to .7 mg/L [source: HHS]. Reasons cited for the change include new science (presumably on rising rates of dental fluorosis among children) and prevalence of fluoride in other sources. Let's look at these and other factors affecting how much fluoride might be too much:

  • Children 8 Years and Younger: In the U.S., the main health risk of too much fluoride is dental fluorosis (staining and pitting of tooth enamel). Children are especially susceptible because dental fluorosis only affects developing teeth. For this reason, the CDC recommends limiting fluoride containing products and using an alternative source of water for children 8 years and younger if public water supplies contain more than 2 mg/L of fluoride [source: CDC].
  • Naturally Occurring Fluoride: The EPA's MCLG (maximum contaminant level goal) for fluoride is 4 mg/L. In some communities, such as the Rocky Mountains, naturally occurring fluoride exceeds this level and water bureaus are actually required to defluoridate public drinking water. Check your water's fluoride level at this site.
  • Products Containing Fluoride: The CDC estimates that people get up to 75% of their fluoride intake from drinking water and processed beverages like juice and soda [source: CDC]. Since food, dental products and pesticides may also contain fluoride, it can be relatively easy to exceed the recommended levels of fluoride, especially if you accidentally swallow your toothpaste!

In moderate amounts (.7 to 1.2 mg/L), fluoride helps prevent tooth decay. However, in excess (the level that constitutes excess ranges from more than 1.5 mg/L, according to the World Health Organization, to more than 4 mg/L according to the EPA), dental fluorosis, bone deposits and more serious conditions like skeletal fluorosis can occur [source: WHO]. In places like the United States where fluoride levels are regulated should not exceed the EPA MCLG of 4 mg/L, mild dental fluorosis is the main health risk.

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Since dental fluorosis only affects children whose permanent teeth haven't come in yet, parents of children 8 and under should take special care to limit the amount of fluoride their kids ingest. People living in areas with lots of naturally occurring fluoride should also monitor their consumption of fluoride-containing products.

Find lots more fluoride facts on the next page.

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More Great Links

Sources

  • American Dental Association. "Fluoride & Fluoridation." (September 6, 2011). http://www.ada.org/fluoride.aspx
  • Environmental Protection Agency. "Basic Information about Fluoride in Drinking Water." July 1, 2011. (Sept. 6, 2011) http://water.epa.gov/drink/contaminants/basicinformation/fluoride.cfm
  • Centers for Disease Control."Community Water Fluoridation." July 11, 2011. (Sept. 6, 2011) http://www.cdc.gov/fluoridation/
  • "Centers for Disease Control."Prevalence and Severity of Dental Fluorosis in the United States, 1999-2004." November 2010. (Sept. 12, 2011) http://www.cdc.gov/nchs/data/databriefs/db53.htm
  • Centers for Disease Control. "Ten Great Public Health Achievements." April 2, 1999. (Sept. 6, 2011) http://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm
  • Chandler, David L. "How Much Fluoride is Too Much?" Boston Globe. Nov. 25, 1985. (Sept. 6, 2011) http://www.fluoridealert.org/health/epa/media/bglobe851125.html
  • Department of Health and Human Services. "HHS and EPA Announce New Scientific Assessments and Actions on Fluoride." Jan. 7, 2011. (Sept. 6, 2011) http://www.hhs.gov/news/press/2011pres/01/20110107a.html
  • Marthaler, T.M. and P.E. Petersen. "Salt Fluoridation - An Alternative in Automatic Prevention of Dental Caries." International Dental Journal. 2005. (Sept. 6, 2011) http://www.who.int/oral_health/publications/orh_IDJ_salt_fluoration.pdf
  • Martin, Brian. "The Sociology of the Fluoridation Controversy: A Reexamination." UOW.EDU.AU (originally published in Sociology Quarterly, Vol. 30, No. 1,1989). 1989. (Sept. 6, 2011) http://www.uow.edu.au/~bmartin/pubs/89sq.html
  • National Institute of Dental and Craniofacial Research. "The Story of Fluoridation." March 25, 2011. (Sept. 6, 2011) http://www.nidcr.nih.gov/oralhealth/topics/fluoride/thestoryoffluoridation.htm
  • USA Today. "U.S. Says Too Much Fluoride In Water." Jan. 7, 2011. (Sept. 6, 2011) http://www.usatoday.com/yourlife/health/medical/2011-01-07-too-much-fluoride_N.htm
  • World Health Organization. "Fluoride." 2011. (Sept. 12, 2011) http://www.who.int/water_sanitation_health/naturalhazards/en/index2.html

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