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Fluoride in Water
by Josh Holcombe
Physical Geology
Spring 2015

                                                                                Fluoride: Adverse Effects on Human Health

             In modern day America, there is an increasing amount of issues that we are recently becoming aware of.  Many of these issues are regarding different everyday practices, and how they could possibly be having a major negative effect on our health.  Everyday new research comes out about how various chemicals that have been continuously put into our air, water, and food are having a negative impact on our health and the developing minds and bodies of our children.  One of the major issues, currently facing our nation today, is the use of fluoride.  Fluoride has been, and is currently being pumped into a very large majority of the countries clean water supply because it has apparent positive effects on dental hygiene.  But is there a possibility that the amount of fluoride continuously being consumed is having a negative effect on the body and the mind?  More and more studies coming out show that fluoride may play a huge role in negatively effecting the development of the brains and bodies of those who drink it. 


Fluoride is a non-organic ion of the chemical fluorine. It is a mineral that can be found naturally in the earth.  Fluoride is released into the water, air, and soil from rocks, and is found in small amounts in every human being.  One of the major ways that fluoride is utilized today is in dental practices.  Fluoride helps in the prevention of tooth decay.  When teeth are exposed to sugar, the sugar creates an acid that eats away at tooth enamel.  Fluoride aids in the rebuilding of tooth enamel, and helps in further prevention of tooth decay (Center for Disease Control).  In certain parts of the world there is a lot of naturally occurring fluoride in the ground water, but in places like the United States, the governments adds fluoride to the water to reduce the amount of dental problems, by continuously exposing a majority of the population to fluoride, through the water system.  This is called fluoridation.  


Water fluoridation first began in the United States in 1962.  Currently 39 states are participating in the water fluoridation program.  The Public Health Service guidelines for the optimal amount of fluoride in the drinking water is 0.7 mg per liter, recently brought down from 1.5mg per liter (U.S. Department for Health and Human Services).  The Environmental Protection Agency’s gives sets the naturally occurring water fluoride limit to 4mg per Liter (Center for Disease Control: Community Water Fluoridation: FAQ).  Just as there is benefits to having a controlled amount of fluoride, there are also serious negative effects of ingesting an excess amount of fluoride.  One of the major concerns about the countries fluoridation system is dosage control.  Some people drink more water than another, like people that play sports and people that work on farms (Campbell, 2013).  If just a small excess amount has been ingested, there is a risk of dental fluorosis.  At higher excess rates of ingested fluoride, there is a high risk for fluoride poisoning, which can develop into issues later in life.

Fluoride Poisoning

Fluoride poisoning is caused by exposure to excess amounts of fluoride.  Acute symptoms of fluoride poisoning can be recognized in levels as low as 1mg per kg of body weight (World Health Organization).  Fluoride can be extremely toxic, an article on MedScape about fluoride toxicity states “Ingested fluoride can form hydrofluoric acid in the stomach, which leads to GI irritation or corrosive effects.” (MedScape).  Symptoms of fluoride intoxication include hyper salivation, vomiting, and diarrhea.  The main effects of fluoride poisoning are gastral intestinal. In more extreme cases it may cause seizures and even death, mainly due to respiratory and cardiac problems.  If there is even a small amount of fluoride poisoning happening in the body for prolonged periods of time, it can have a long term negative effects on bones and teeth, causing dental and skeletal fluorosis.

Dental and Skeletal Fluorosis

During development of the teeth, fluoride helps create the crystalline structure that makes up the inside of the teeth.  Depending of the concentration of fluoride the structure of the tooth becomes more porous the more fluoride is in the tissue during development.  Dental fluorosis is when there is an excess amount of fluoride and the teeth becomes increasingly more porous as the severity of the condition increases (Mascarenhas, 2000).  Dental fluorosis in mild and moderate forms is white streaking and spotting on the surface of the teeth, and in more severe forms teeth with have brown spots and pitting.  Dental fluorosis can begin from anywhere between 0.9 and 1.2 mg per liter of water when being ingested on a regular basic (World Health Organization).

           In addition to tooth enamel, even higher amounts of fluoride can start to negatively affect skeletal tissue by slowly making fluoride deposits in the bone.  This is called skeletal fluorosis, and can begin to be seen in levels of about 3 to 6mg per liter of drinking water.  Extreme forms of skeletal fluorosis begin at 10 mg per liter, these forms of skeletal fluorosis can be crippling (World Health Organization).  Fluorosis is the long term effect of consistent exposure to excess levels of fluoride that take place in the human body. In the United States the currents recommendations for water fluorination in order to prevent dental problems is .7mg Liter of drinking water.  Take into considerations this recommendation was just recently brought down from .7mg – 1.2 mg per Liter just in 2015. (Mascarenhas, 2000).

Adverse Effects on Children’s Intelligence Quotient (IQ)

            One large theory is that fluoridation of the water is having an adverse effects on children’s Intelligence quotient.  However, no known studies have been done on American children.  Most of the studies done are done on the correlation between water fluoridation and the IQ level of children in places in China and India where the water is being fluoridated naturally.  Studies cannot be conducted in the United States because there is no way to know how much fluoride each of the population has ingested, or if there is even anybody at all that is not ingesting it.  Several meta-analyses confirm that there is definitely a positive correlation between fluoride intake and low IQ level in these countries where natural fluoride is occurring compared to similar cities in the same area that have no water in the fluoride at all. (Cheng, H., & Lynn, R., 2013., Sebastian, S., & Sunitha, S., 2015., Saxena, S., Sahay, A., & Goel, P., 2012). 


After reviewing several studies, and many different articles on the possible toxic effects of fluoride, it is evident that fluoride can, and does have a negative effect on people on a short term level and a long term level.  This should be a huge eye opener for any city that decides to participate in adding fluoride to the public’s supply of drinking water.



Campbell, A. W., M.D. (2013). Fluoride: What are the facts? Alternative Therapies in Health and Medicine , 19(5), 8-10. Retrieved from the ProQuest database.

Cheng, H., & Lynn, R. (2013). The adverse effect of fluoride on children's intelligence: A systematic review. Mankind Quarterly, 53(3), 306-347. Retrieved from the ProQuest database.

Center for Disease Control. (2013, July 25). Fluoridation Basics. U.S. Department of Heath and Human Services. Retrieved from

Center for Disease Control. (2015, April 20). Community Water Fluoridation: FAQ. U.S. Department of Health and Human Services. Retrieved from

Mascarenhas, K., Anna, BDS, DrPH. (2000). Risk Factors for Dental Fluorosis: A review of the recent literature. American Academy of Pediatric Dentistry. 22:4. 269-277.  

Sebastian, S., & Sunitha, S. (2015). A cross-sectional study to assess the intelligence quotient (IQ) of school going children aged 10-12 years in villages of Mysore district, India with different fluoride levels. Journal of the Indian Society of Pedodontics and Preventive Dentistry, 33(4), 307-311. doi:
Saxena, S., Sahay, A., & Goel, P. (2012). Effect of fluoride exposure on the intelligence of school children in Madhya Pradesh, India. Journal of Neurosciences in Rural Practice, 3(2), 144-149. doi:
Shin, D., Richard. (2016, Feb. 7). Fluoride Toxicity. Medscape. Retrieved from  

U.S. Department for Health and Human Services Federal Panel of Community Water Fluoridation.(2015). U.S. Health Public Service Recommendation for Fluoride Concentration in Drinking Water for the Prevention of Dental Caries. Public Health Reports, 130, 1-14.  

World Health Organization. (2004). Fluoride in Drinking-water: Background Document of Development of WHO Guidelines for Drinking-water Quality. Retrieved from