Based on nearly 100 randomized controlled trials, fluoride toothpaste reduces dental cavity rates, but what about just adding fluoride to the water supply?
Why Is There Fluoride in Water? Is It Effective?
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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Intro: In this five-part series I look at the history, benefits, and safety of water fluoridation, AND why I changed my mind about it.
A meta-analysis of all the studies on the dental health implications of vegetarian diets showed significantly fewer decayed teeth, missing teeth, and the number of teeth with fillings. One of the studies that bucked the trend and showed that vegetarians had more cavities blamed the excess decay on the fact that vegetarians were significantly less likely to choose fluoride-containing toothpaste, supported by the fact that those who did use toothpaste with fluoride had significantly fewer decayed teeth than those who didn’t.
Fluoride is thought to protect teeth by improving the intrinsic stability of the mineral structure of dental enamel. A recent meta-analysis of nearly 100 randomized controlled trials of fluoride toothpaste involving more than 10,000 people found “high-certainty” evidence that toothpaste containing the typical amount of fluoride reduces tooth decay significantly more than non-fluoride toothpaste in both children and adults. But what about the addition of fluoride to the water supply?
A medical consensus of public health authorities around the world has considered water fluoridation at appropriate levels as a safe and effective means to prevent cavities on a community-wide scale. In fact, the CDC, the US Center of Disease Control and Prevention, deemed fluoridation of drinking water as one of the top ten public health achievements of the 20th century. However, community water fluoridation has long been a flashpoint of polemic and polarization. Anti-fluoridation activists underscore that there is no human dietary requirement for fluoride, and argue that water fluoridation isn’t effective enough to justify the costs, which may include health risks.
First, some background before I dive into the controversy. Fluoride is a mineral element in the Earth’s crust that naturally occurs in most water supplies. This is one of the reasons fluoridation has withstood constitutional challenges. Courts have ruled that rather than an added medication, fluoride can be seen as a nutrient found naturally in some areas but not others, and fluoridation of water supplies is a matter of just leveling the playing field––particularly for poor communities who may have limited access to dental care. Fluoridation can be defined as “the upward or downward adjustment of the level of fluoride content in drinking water to an optimal level just enough to prevent cavities but not enough to cause fluorosis,” or cosmetic changes in the teeth.
It all started in 1901 with an investigation into Colorado Brown Stain, “grotesque” brown stains on the teeth of Colorado Springs residents. At the same time, teeth afflicted by the condition were “surprisingly and inexplicably resistant to decay.” After fluoride was identified as the basis for these changes, a nationwide survey of fluoride levels in drinking water in the 1930s led to the discovery that fluoride could reach levels around one part per million without causing serious fluorosis. Hoping to get the best of both worlds, Grand Rapids, Michigan, in 1945, became the first city in the world to fluoridate its water supply. Within 11 years, cavity rates among children in Grand Rapids were reportedly down more than 60 percent, and a fluoridation movement was born. Today, about two dozen countries fluoridate their drinking water. Dozens of others have naturally fluoridated water, or instead add fluoride to milk or table salt.
Fluoridation pushback started almost immediately in the United States. The obsession of Dr. Strangelove’s Colonel Ripper with the purity of his “precious bodily fluids” was based on real-life right-wing Red Scare conspiracy theories that fluoridation was meant to produce “moronic, atheistic slaves” who would bow to the communists.
Today’s social media is also rife with anti-fluoridation messages. Studies have found that 63 percent of Instagram posts regarding fluoride could be classified as anti-fluoride, 64 percent of tweets on Twitter, 99 percent of YouTube videos, and up to 100 percent of fluoride groups and pages found on Facebook were anti-fluoride. Years before COVID, the anti-fluoridation crusade was considered a case study of “digital pandemics of public health misinformation.” In the year before COVID, the first worldwide survey of the crisis of confidence in science of 140,000 people in 140 countries found that only 18 percent of humanity appeared to have a “high” level of trust in science. To my pleasant surprise though, despite so many institutional failures, a 2020 follow-up of the survey found trust in science actually increased after COVID.
Where does the science land on water fluoridation? First, let me address efficacy. The CDC attributes the steep decline in dental decay in the United States in the latter half of the 20th century to water fluoridation. But similar declines were noted in non-fluoridated countries––attributed in large part to the widespread global distribution of fluoride toothpaste. The best evidence we have comes from prospective studies with concurrent controls, comparing cavity rates over time in fluoridated versus non-fluoridated populations. There have been more than 100 such studies to date, and overall, fluoridation results in 35 percent fewer decayed, missing, or filled baby teeth, and 26 percent fewer decayed, missing, or filled permanent teeth. So, community fluoridation does indeed help to cut down on cavities. The question then becomes, at what cost?––which we’ll discuss next.
Please consider volunteering to help out on the site.
- Smits KPJ, Listl S, Jevdjevic M. Vegetarian diet and its possible influence on dental health: A systematic literature review. Community Dent Oral Epidemiol. 2020;48(1):7-13.
- Staufenbiel I, Adam K, Deac A, Geurtsen W, Günay H. Influence of fruit consumption and fluoride application on the prevalence of caries and erosion in vegetarians--a controlled clinical trial. Eur J Clin Nutr. 2015;69(10):1156-1160.
- Simmer JP, Hardy NC, Chinoy AF, Bartlett JD, Hu JCC. How fluoride protects dental enamel from demineralization. J Int Soc Prev Community Dent. 2020;10(2):134-141.
- Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database Syst Rev. 2019;3(3):CD007868.
- Unde MP, Patil RU, Dastoor PP. The untold story of fluoridation: revisiting the changing perspectives. Indian J Occup Environ Med. 2018;22(3):121-127.
- Centers for Disease Control and Prevention (CDC). Ten great public health achievements—United States, 1900-1999. MMWR Morb Mortal Wkly Rep. 1999;48(12):241-243.
- Curiel JA, Sanders AE, Christian TML, et al. Fluoridation advocacy in referenda where media coverage is balanced yet biased. J Am Dent Assoc. 2018;149(4):273-280.e3.
- Spencer KF, Limeback H. Blood is thicker than water: Flaws in a National Toxicology Program study. Med Hypotheses. 2018;121:160-163.
- Block LE. Antifluoridationists persist: the constitutional basis for fluoridation. J Public Health Dent. 1986;46(4):188-198.
- Palmer CA, Gilbert JA. Position of the Academy of Nutrition and Dietetics: the impact of fluoride on health. J Acad Nutr Diet. 2012;112(9):1443-1453.
- Bánóczy J, Rugg-Gunn A, Woodward M. Milk fluoridation for the prevention of dental caries. Acta Med Acad. 2013;42(2):156-167.
- Guth S, Hüser S, Roth A, et al. Toxicity of fluoride: critical evaluation of evidence for human developmental neurotoxicity in epidemiological studies, animal experiments and in vitro analyses. Arch Toxicol. 2020;94(5):1375-1415.
- Newbrun E. The fluoridation war: a scientific dispute or a religious argument? J Public Health Dent. 1996;56(5 Spec No):246-252.
- Basch CH, Milano N, Hillyer GC. An assessment of fluoride related posts on Instagram. Health Promot Perspect. 2019;9(1):85-88.
- Mertz A, Allukian M. Community water fluoridation on the Internet and social media. J Mass Dent Soc. 2014;63(2):32-36.
- Seymour B, Getman R, Saraf A, Zhang LH, Kalenderian E. When advocacy obscures accuracy online: digital pandemics of public health misinformation through an antifluoride case study. Am J Public Health. 2015;105(3):517-523.
- Feine J, Jakubovics N. Science in the spotlight: a crisis of confidence? J Dent Res. 2021;100(1):5-7.
- Wellcome Global Monitor 2020: Covid-19. Wellcome. Published November 29, 2021.
- Neurath C. Tooth decay trends for 12 year olds in nonfluoridated and fluoridated countries. Fluoride. 2005; 38(4).
- Iheozor-Ejiofor Z, Worthington HV, Walsh T, et al. Water fluoridation for the prevention of dental caries. Cochrane Database Syst Rev. 2015;2015(6):CD010856.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Intro: In this five-part series I look at the history, benefits, and safety of water fluoridation, AND why I changed my mind about it.
A meta-analysis of all the studies on the dental health implications of vegetarian diets showed significantly fewer decayed teeth, missing teeth, and the number of teeth with fillings. One of the studies that bucked the trend and showed that vegetarians had more cavities blamed the excess decay on the fact that vegetarians were significantly less likely to choose fluoride-containing toothpaste, supported by the fact that those who did use toothpaste with fluoride had significantly fewer decayed teeth than those who didn’t.
Fluoride is thought to protect teeth by improving the intrinsic stability of the mineral structure of dental enamel. A recent meta-analysis of nearly 100 randomized controlled trials of fluoride toothpaste involving more than 10,000 people found “high-certainty” evidence that toothpaste containing the typical amount of fluoride reduces tooth decay significantly more than non-fluoride toothpaste in both children and adults. But what about the addition of fluoride to the water supply?
A medical consensus of public health authorities around the world has considered water fluoridation at appropriate levels as a safe and effective means to prevent cavities on a community-wide scale. In fact, the CDC, the US Center of Disease Control and Prevention, deemed fluoridation of drinking water as one of the top ten public health achievements of the 20th century. However, community water fluoridation has long been a flashpoint of polemic and polarization. Anti-fluoridation activists underscore that there is no human dietary requirement for fluoride, and argue that water fluoridation isn’t effective enough to justify the costs, which may include health risks.
First, some background before I dive into the controversy. Fluoride is a mineral element in the Earth’s crust that naturally occurs in most water supplies. This is one of the reasons fluoridation has withstood constitutional challenges. Courts have ruled that rather than an added medication, fluoride can be seen as a nutrient found naturally in some areas but not others, and fluoridation of water supplies is a matter of just leveling the playing field––particularly for poor communities who may have limited access to dental care. Fluoridation can be defined as “the upward or downward adjustment of the level of fluoride content in drinking water to an optimal level just enough to prevent cavities but not enough to cause fluorosis,” or cosmetic changes in the teeth.
It all started in 1901 with an investigation into Colorado Brown Stain, “grotesque” brown stains on the teeth of Colorado Springs residents. At the same time, teeth afflicted by the condition were “surprisingly and inexplicably resistant to decay.” After fluoride was identified as the basis for these changes, a nationwide survey of fluoride levels in drinking water in the 1930s led to the discovery that fluoride could reach levels around one part per million without causing serious fluorosis. Hoping to get the best of both worlds, Grand Rapids, Michigan, in 1945, became the first city in the world to fluoridate its water supply. Within 11 years, cavity rates among children in Grand Rapids were reportedly down more than 60 percent, and a fluoridation movement was born. Today, about two dozen countries fluoridate their drinking water. Dozens of others have naturally fluoridated water, or instead add fluoride to milk or table salt.
Fluoridation pushback started almost immediately in the United States. The obsession of Dr. Strangelove’s Colonel Ripper with the purity of his “precious bodily fluids” was based on real-life right-wing Red Scare conspiracy theories that fluoridation was meant to produce “moronic, atheistic slaves” who would bow to the communists.
Today’s social media is also rife with anti-fluoridation messages. Studies have found that 63 percent of Instagram posts regarding fluoride could be classified as anti-fluoride, 64 percent of tweets on Twitter, 99 percent of YouTube videos, and up to 100 percent of fluoride groups and pages found on Facebook were anti-fluoride. Years before COVID, the anti-fluoridation crusade was considered a case study of “digital pandemics of public health misinformation.” In the year before COVID, the first worldwide survey of the crisis of confidence in science of 140,000 people in 140 countries found that only 18 percent of humanity appeared to have a “high” level of trust in science. To my pleasant surprise though, despite so many institutional failures, a 2020 follow-up of the survey found trust in science actually increased after COVID.
Where does the science land on water fluoridation? First, let me address efficacy. The CDC attributes the steep decline in dental decay in the United States in the latter half of the 20th century to water fluoridation. But similar declines were noted in non-fluoridated countries––attributed in large part to the widespread global distribution of fluoride toothpaste. The best evidence we have comes from prospective studies with concurrent controls, comparing cavity rates over time in fluoridated versus non-fluoridated populations. There have been more than 100 such studies to date, and overall, fluoridation results in 35 percent fewer decayed, missing, or filled baby teeth, and 26 percent fewer decayed, missing, or filled permanent teeth. So, community fluoridation does indeed help to cut down on cavities. The question then becomes, at what cost?––which we’ll discuss next.
Please consider volunteering to help out on the site.
- Smits KPJ, Listl S, Jevdjevic M. Vegetarian diet and its possible influence on dental health: A systematic literature review. Community Dent Oral Epidemiol. 2020;48(1):7-13.
- Staufenbiel I, Adam K, Deac A, Geurtsen W, Günay H. Influence of fruit consumption and fluoride application on the prevalence of caries and erosion in vegetarians--a controlled clinical trial. Eur J Clin Nutr. 2015;69(10):1156-1160.
- Simmer JP, Hardy NC, Chinoy AF, Bartlett JD, Hu JCC. How fluoride protects dental enamel from demineralization. J Int Soc Prev Community Dent. 2020;10(2):134-141.
- Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database Syst Rev. 2019;3(3):CD007868.
- Unde MP, Patil RU, Dastoor PP. The untold story of fluoridation: revisiting the changing perspectives. Indian J Occup Environ Med. 2018;22(3):121-127.
- Centers for Disease Control and Prevention (CDC). Ten great public health achievements—United States, 1900-1999. MMWR Morb Mortal Wkly Rep. 1999;48(12):241-243.
- Curiel JA, Sanders AE, Christian TML, et al. Fluoridation advocacy in referenda where media coverage is balanced yet biased. J Am Dent Assoc. 2018;149(4):273-280.e3.
- Spencer KF, Limeback H. Blood is thicker than water: Flaws in a National Toxicology Program study. Med Hypotheses. 2018;121:160-163.
- Block LE. Antifluoridationists persist: the constitutional basis for fluoridation. J Public Health Dent. 1986;46(4):188-198.
- Palmer CA, Gilbert JA. Position of the Academy of Nutrition and Dietetics: the impact of fluoride on health. J Acad Nutr Diet. 2012;112(9):1443-1453.
- Bánóczy J, Rugg-Gunn A, Woodward M. Milk fluoridation for the prevention of dental caries. Acta Med Acad. 2013;42(2):156-167.
- Guth S, Hüser S, Roth A, et al. Toxicity of fluoride: critical evaluation of evidence for human developmental neurotoxicity in epidemiological studies, animal experiments and in vitro analyses. Arch Toxicol. 2020;94(5):1375-1415.
- Newbrun E. The fluoridation war: a scientific dispute or a religious argument? J Public Health Dent. 1996;56(5 Spec No):246-252.
- Basch CH, Milano N, Hillyer GC. An assessment of fluoride related posts on Instagram. Health Promot Perspect. 2019;9(1):85-88.
- Mertz A, Allukian M. Community water fluoridation on the Internet and social media. J Mass Dent Soc. 2014;63(2):32-36.
- Seymour B, Getman R, Saraf A, Zhang LH, Kalenderian E. When advocacy obscures accuracy online: digital pandemics of public health misinformation through an antifluoride case study. Am J Public Health. 2015;105(3):517-523.
- Feine J, Jakubovics N. Science in the spotlight: a crisis of confidence? J Dent Res. 2021;100(1):5-7.
- Wellcome Global Monitor 2020: Covid-19. Wellcome. Published November 29, 2021.
- Neurath C. Tooth decay trends for 12 year olds in nonfluoridated and fluoridated countries. Fluoride. 2005; 38(4).
- Iheozor-Ejiofor Z, Worthington HV, Walsh T, et al. Water fluoridation for the prevention of dental caries. Cochrane Database Syst Rev. 2015;2015(6):CD010856.
Motion graphics by Avo Media
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Title
Why Is There Fluoride in Water? Is It Effective?
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
Like everything in medicine, it’s a matter of balancing the risks and benefits.
This is the first video in a five-part series on water fluoridation. Stay tuned for:
- Side Effects of Water Fluoridation: Dental Fluorosis
- Is Water Fluoridation Safe?
- Why I Changed My Mind on Water Fluoridation
- Medicine’s Response to the Changing Science on Fluoride Safety
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