Fundamentals of Human Nutrition/Fluoride

11.9 FluorideEdit

Although Fluoride will not appear on the periodic table, it is a naturally occurring material. This material can be found in water, animals, soil, and even plants. Fluoride protects individuals from cavities while strengthening the outer layers of their teeth; this protection works against acid that causes tooth deterioration.

Fluoride can be obtained through drinking water. “From 1966 to 1994, the percentage of 12 year-olds in the United States with decayed, missing (due to cavities) or filled teeth declined 68% (CDC, 2003).” For the past couple of centuries, there have been additions of fluoride to water supplies to assist in preventing tooth decay. The concentration of fluoride in water was increased to about 0.7 mg per liter of water. Statistics show that before this water fluoridation, children in local areas had about three times as many cavities. Following this introduction to water supplies, the Center for Disease Control ruled that this was one of the top ten advancements of public health of the twentieth century.

In the body, fluoride works with other minerals in mineralizing bones and teeth. However, fluoride takes the role of replacing the hydroxyl bonds of the crystals formed in this process, called flourapatite (which helps to build up the strength in teeth and prevent decay). In dentistry, about 95% of the population have some sort of oral issue. Problems such as deteriorated teeth, missing teeth, or artificial enhanced teeth are incorporated in this number. While these issues may seem to be simple, a simple tooth ache can result in a chain reaction of problems to an individual’s health. Headaches, problems eating, etc., are problems that should never be overlooked. With the introduction of fluoride, these problems will not completely erase. However, the chances for these problems to take place are greatly decreased. (Bi WJ, 2010)

While fluoride can enhance protection of teeth, it can also be a detriment when too much of it is consumed. Fluorosis is the act of damaging teeth with too much fluoride. In patients where there is too much fluoride, there will be a presence of white pecks on the teeth. However, in extreme cases the teeth can be a permanently stained. This condition can only occur doing the development stages of teeth, and is permanent. It is imperative that teeth are well taken care of in the first couple of years in lives of children. Also making sure that children are not swallowing toothpaste or mouthwashes can help prevent this issue.

Fluoride is a natural mineral that helps protect teeth. Everyday, teeth go through mineralization and demineralization; the enamel gets broken down (demineralization) and built back up (mineralization). During mineralization, there are these tiny crystals that are called hydroxyapatite (Whitney & Rolfes, 2013). The teeth become stronger and more resistant to decay due to fluoride, which replaces the hydroxol portions of the hydroxyapatite crystal, forming fluorapatite (Whitney & Rolfes, 2013). With fluoride, teeth can fight acid and other factors that lead to tooth decay, one of the top health problems in the United States. A very large margin of the U.S. population (roughly 95%) has had some sort of dental issue, whether the tooth (or teeth) was decayed, filled, or missing (Whitney & Rolfes, 2013). Stemming from a lack of fluoride is decay, which can lead to a multitude of other issues. Included in these issues is tooth loss and overall mass tooth decay, which can inhibit the ability to chew and consume a variety of different foods.

Anna L. Choi & Guifan Sun & Ying Zhang & Philippe Grandjean Environ Health Perspect. (2012) Retried from Book 120(10): 1362–1368.

Bi WJ, (2010) Analysis on test results of drinking water’s quality in Janan Railway Bureau from 2005–2009.

Centers for Disease Control and Prevention (2003). Recommendations for using fluoride to prevent and control dental caries in the United States.

Whitney, E., & Rolfes, S. (2005). Understanding nutrition (10th ed.). Belmont, CA: Thomson/Wadsworth.

Whitney, E., & Rolfes R. S. (2013). Understanding Nutrition. Stamford, CT: Cengage Learning.

11.9.1 SourcesEdit

Fluoride, an anion of the chemical element fluorine, can be found across the globe. It is a natural component of the earth’s crust (ATSDR, 2003) and it is present in trace amounts as a mineral in soil, although quantities vary depending on the natural characteristics of soil in different areas, and in some rocks. Furthermore, fluoride is present to an extent in natural water sources, including oceans. Plants can absorb fluoride from the surrounding soil when they absorb water through their roots. Animals, including humans, can then gain fluoride by consuming these plants and natural water sources. Additional natural sources of fluoride include seafood and tea (Whitney, 2013).

With an adequate intake (“adequate intake” is a recommended value for nutrient intake created when a recommended daily allowance cannot be calculated (Whitney, 2013)) set at 4 milligrams per day (mg/day) for men and 3 mg/day for women, it is virtually impossible to meet daily recommendations for fluoride through only consuming these natural sources. This is evident when one looks at a 2005 USDA report that catalogued the average fluoride content for some common sources; the fresh fruit with the highest fluoride concentration was grapes at only 8 micrograms per 100 grams and the majority of vegetables came in under 10 micrograms per 100 grams (Nutrient, 2005). The primary source of fluoride, particularly in American diets, is artificial water fluoridation. This is supported by the 2005 USDA report.

Public water supply has been artificially fluoridated (having fluoride added) in the United States to some extent since 1945, after researchers concluded that increased fluoride levels resulted in fewer dental caries and better overall teeth and oral health. Fluoridation spread throughout the country and is now commonplace. In 2004, 67% of those individuals that utilized a public water system received artificially fluoridated water (Tiemann, 2008). The optimal fluoridation level recommended by the U.S. Public Health Service is between 0.7 and 1.2 milligrams per liter. The lower end of this range is recommended for warmer climates, where more water is expected to be consumed on average, and the upper end is recommended for colder climates, where less water is consumed on average (Committee, 2006). Artificial fluoridation is also supported by the World Health Organization for areas where natural fluoride levels are low (Tiemann, 2008).

Depending on the bottler and water source, fluoride may or may not be present in bottled water (Nutrient, 2005).

Another major source of fluoride is toothpaste. Fluoride toothpaste is used by over 90% of the United States’ population. Toothpaste, as a source of fluoride, differs from other sources because it applies the fluoride topically, directly to the teeth, rather than through ingestion. This has been shown to be a more effective manner of preventing dental caries, however public water remains an integral source of fluoride and a major contributor to dental health. A 2010 study concluded that primarily using non-fluoridated water was one of the top three factors associated with dental problems in teens (Campaign, 2015).

In summary, fluoride can be found in trace amounts in many foods (including fruits, vegetables, and beef) as well as natural water sources, but the primary source is artificially fluoridated public water. Other than fluoridated water, the top sources for fluoride are tea, seafood, and toothpaste.


Agency for Toxic Substances and Disease Registry (ATSDR). (2003). Toxicological Profile for Fluorides, Hydrogen Fluoride, and Fluorine. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Campaign for Dental Health, American Academy of Pediatrics. (2015). The Debate over Fluoridated Water. Retrieved from

Committee on Fluoride in Drinking Water, National Research Council of the National Academies. (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. Washington, D.C.: The National Academies Press

Nutrient Data Laboratory, Agricultural Research Service, US Department of Agriculture. (2005). USDA National Fluoride Database of Selected Beverages and Foods, Release 2.

Tiemann, M. R. (2008). Fluoride in Drinking Water: Review of Fluoridation and Regulation Issues.

Whitney, E., & Rolfes S. R.. (2013). Understanding Nutrition, 14th Edition. Stamford, CT: Cengage Learning

“How does one get fluoride?” someone may ask. The most common source of fluoride is actually found in drinking water. According to the American Dental Association, the Centers for Disease Control and Prevention has proclaimed community water fluoridation one of the ten greatest public health achievements of the 20th Century (“Fluoride”, n.d.). Oddly enough though, fluoridated water is more easily found in tap water than bottled water, as traditional bottled water is not fluorinated unless specified (Whitney & Rolfes, 2013). According to the CDC, the goal by 2020 is to have 79.6% of people on public water to have access to fluorinated water (“Water Fluoridation Data & Statistics”, 2015). There are various maps and websites online that can show by state and even by county the level of fluoridation in the water. In addition to water, fluoride can also be found in another everyday usage. As obvious as it may seem, brushing with fluoridated toothpaste has dropped the number of cavities drastically over the years. When one sees a product with the ADA Seal of Approval, they can be sure they are getting a product that comes from a safe and effective lab, uses FDA-approved ingredients, comes from a company that uses scientifically based ads and packaging, and comes from the highest manufacturing standards (“ADA Seal of Acceptance Program and Products”, n.d.). While brushing, one can actually get two sources of fluoride at once with the toothpaste and the water. Mouthwashes also contain fluoride, which are another essential part to the dental hygiene regime to keep one’s mouth happy and healthy. If a child has serious risk of developing cavities due to lack of fluoride in the water supply and through poor dental hygiene, a doctor may prescribe a fluoride supplement if needed (“Fluoride”, n.d.). This is why it is important to start children young when it comes to dental hygiene. It has been shown that fluoride toothpastes can reduce the number of cavities in children by 15%-30% and the fluoridation of water can reduce the risk by up to another 40% (Zissu, 2014)!

Fluoride. (n.d.). Retrieved December 1, 2015, from

ADA Seal of Acceptance Program and Products. (n.d.). Retrieved December 2, 2015, from

Water Fluoridation Data & Statistics. (2015, July 29). Retrieved December 2, 2015, from

Whitney, E., & Rolfes R. S. (2013). Understanding Nutrition. Stamford, CT: Cengage Learning.

Zissu, A. (2014, February 4). The Fluoride Conundrum: Is Fluoride Safe For Kids? Retrieved December 2, 2015, from fluoride-safe-for-kids/

11.9.2 FunctionsEdit

11.9.3 RequirementsEdit

11.9.4 ImbalanceEdit

In 1945 the United States government issued the process of community water fluoridation (Long & Zhang 2009). Since then fluoride has been added to toothpaste, food items, dental treatment, dental implants, and many antibiotics. This increase in the consumption of fluoride has led many to observe the biological effects of fluoride imbalance in relation to the human body. In taking an excess amount of fluoride presents a numerous amount of potential problems, but seems to have a noticeably negative effect on hormones.

Studies have shown that excess fluoride can negatively affect both male and female sex hormones. Researchers in China developed study in which some men were exposed to high doses of fluoride each day, while others obtained a regular amount each day. Those who consumed more fluoride than required expressed significantly lower levels of testosterone, decreased sperm levels, reduced fertility rates, and physical changes in the reproductive system (Long & Zhang). In relation to the effects of excess fluoride on the sexual hormones in women, studies have shown drastic decreases in fertility rates, as well as decreased in progesterone, testosterone, estradiol, luteinizing hormone, and follicle stimulating hormone (Freni 1994).

Increased fluoride consumption can also be correlated to an increase in occurrences of underactive thyroid. Although no cause and effect relationship has been proven, researchers advise caution when consuming fluoride. A study led by Stephen Peckham was created to find scientific evidence that fluoride indeed has an opposing effect on the thyroid gland. The study revealed that cities with tap water that exceeded 0.3 milligrams of fluoride per liter, were 30% more likely to experience underactive thyroid glands compared to other residents (Mezitis 2015).

Children are at a greater risk of fluoride imbalance due to their disproportionate body size. Children between the age of one and seven cannot drink more than one liter of water that has went through fluoridation, without receiving excess fluoride (Caries 1993). It is essentially to inhibit children of these ages from using fluoride based toothpaste in order to avoid any thyroid defects, and reproductive alterations.

Because there is no essential requirement for fluoride in the body, it is easy to intake more than necessary. If there is a zero intake of fluoride in the body, no deficiency state will occur. The only true need presented to us by toothpaste commercials, and dentist is the need to fight cavities, and build stronger, cleaner, and more sustainable teeth. With this in mind, it is important for individuals to know that fluoride is not a necessity, but an option. When consuming fluoride, it is important to monitor the amounts, and take caution.

1. Hu Long, Liang Zhang, “Fluoride Toxicity In The Male Reproductive System.” Study Review Fluoride 42(4)260–76, Oct-Dec 2009. 2. Freni SC. “Exposure to Excess Fluoride and Fertility Rates.” Journal of Toxicology and Environmental Health 1994 May;42(1):109–21. 3. Spyros Mezitis, M.D., endocrinologist, New York City, 2015, Journal of Epidemiology & Community Health 4. W. Künzel, et al. “Decline of caries prevalence with water fluoridation.” Community Dentistry and Oral Epidemiology Vol 28, Issue 5, pages 382–9, October 2000. 5. Kalsbeek H. Caries “Experience of Children after Discontinuation of Water Fluoridation.” Caries Res 1993;27:201–5.