Fluoride is a common element found naturally in most of the world's water sources. It is the 13th most abundant element in the Earth’s crust. As water flows through the various layers of rock it is generally imparted somewhere between near zero and 10 parts per million of fluoride.
The element has been lauded in recent decades for its ability to prevent tooth decay. Acids and bacteria can eat away at enamel over time. However, enamel that has been exposed to fluoride at appropriate concentrations forms molecules of fluorapatite, which is less acid soluble, and thus helps prevent cavities. Most public water systems and bottled waters in the United States are infused with fluoride to the concentration of 0.7 - 1.2 parts per million (Main, 2015). While fluoride may prevent cavities at certain levels it also can have negative dental effects at higher levels.
Dental fluorosis occurs when teeth are exposed to too much fluoride. The effects can range from mild white streaks to severe, brown stains, pits and broken enamel. As of 2010, 41 percent of kids ages 12 to 15 had some form of dental fluorosis, according to the CDC (Main, 2015). A comprehensive report on fluoride was published in 2006 by the National Research Council, and found that the upper limit for fluoride, at 4 ppm, was too high to prevent kids from developing severe dental fluorosis and recommended the EPA lower this limit (Committee on Fluoride in Drinking Water, 2006) Additionally, skeletal fluorosis can occur when fluoride becomes concentrated in the bone inciting increased bone growth, altering tissue structure, and weakening the skeleton (Davis, n.d.).
In June 2015, the Cochrane Collaboration, a global network of researchers and health care professionals, published a report that analyzed 20 past studies on water fluoridation. They found that while water fluoridation is effective at reducing tooth decay in children, “no studies that aimed to determine the effectiveness of water fluoridation for preventing caries [cavities] in adults met the review’s inclusion criteria” (Davis, n.d.).
Additionally, preliminary research in laboratory animals suggests that high levels of fluoride may be toxic to brain and nerve cells. Studies on humans have identified possible links to learning, memory, and cognition deficits (Davis, n.d.). A study published in 2012 found a link between high fluoride levels, and lower IQs in children. The paper looked at the results of 27 different studies, 26 of which found a link between high-fluoride drinking water and lower IQ (Choi et al., 2012). Additionally we see an effect of fluoride on the pineal gland. The pineal gland is an endocrine gland whose main function is the biosynthesis and secretion of melatonin, a hormone responsible for regulating circadian rhythms. The pineal gland may accumulate significant amounts of calcium and fluoride, making it the most fluoride-saturated organ of the human body. Both the calcification and accumulation of fluoride may result in melatonin deficiency (Chlubek & Sikora, 2020).
Thus we see that beyond childhood fluoride exposure has limited dental effects and quite far reaching physiological effects. Fluoride may help with the prevention of cavities, but beyond its topical application to enamel, the ingestion and absorption of fluoride presents itself only as a toxin. Something to consider when eating, drinking, or buying that next tube of toothpaste.
Chlubek, D., & Sikora, M. (2020, April 22). Fluoride and Pineal Gland. Applied Sciences. https://www.mdpi.com/2076-3417/10/8/2885/pdfFluoride and Pineal Gland Dariusz Chlubek 1,* and Maciej Sikora
Choi, A., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis. Environmental Health Perspectives, 120(10), 1362–1368. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/
Committee on Fluoride in Drinking Water. (2006). FLUORIDE IN DRINKING WATER. THE NATIONAL ACADEMIES PRESS. https://www.nap.edu/read/11571
Davis, N. (n.d.). Is Fluoridated Drinking Water Safe? Harvard Public Health. https://www.hsph.harvard.edu/magazine/magazine_article/fluoridated-drinking-water/
Main, D. (2015, 5 1). Facts About Fluoridation. Live Science. https://www.livescience.com/37123-fluoridation.html
Staff at Mission Health & Wellness regularly contribute to this blog including Nick Carlo, Hannah Roeter, Courtney Mohr Taylor, and Dr. Kristen Acesta