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Why do we have fluoride in our water?

What is flouride?

Fluoride is a naturally occurring mineral found in soil, fresh water, and in whole foods like eggs, fruit, and milk. It can also be added or fortified to dental products, drinking water, and various other chemical products to improve oral health where fluoride is deficient or lacking. You might recognize fluoride as one of the “active ingredients” on your toothpaste and mouthwash.

Studies have shown that introducing additional fluoride into the water supply in geographical areas where naturally occurring levels are low can help reduce the incidence of tooth decay in the area’s population, so it is often added to municipal water supplies. This fortification helps prevent tooth decay, which is one of the most common health problems affecting children, and reduces the costs of dental care for people around the world.

Adding fluoride to drinking water may seem like a simple solution to bolstering dental health, but it is not without its critics. Some researchers have voiced their concerns about its effect on health, particularly with how it affects the bones, teeth, and neurological development, especially in children. We will go over how fluoride works, its benefits and risks, side effects, and recommended amounts.

Fast facts about fluoride

  • Fluoride is derived from fluorine, an abundant and naturally occurring element.
  • Fluoridation of water reduces the incidence of tooth decay in the general population.
  • Fluoride protects teeth from decay via demineralization by the process of remineralization.
  • Ingesting an excessive amount of fluoride can lead to dental or skeletal fluorosis, which causes damage to bones and joints.

How does it work?

Fluoride prevents tooth decay by providing an environment that allows the formation of better quality enamel by reducing the ability of bacteria in the mouth to produce acid. When the bacteria combine with the sugars we ingest through food and drinks, acid is produced, which erodes tooth enamel and causes cavities and other damage. This process is called demineralization. Fluoride remineralizes the teeth by collecting in the demineralized areas to strengthen the enamel.

How much fluoride is recommended?

The Department of Health and Human Services (DHHS) is responsible for determining the most beneficial level of fluoride for preventing tooth decay and promoting public health. The currently accepted level is 0.7 ppm (parts per million), or 0.7 milligrams (mg) of fluoride in every liter of water. From 1962 to 2015, the previous upper limit was from 0.7 to as high as 1.2 ppm, before the revision to 0.7 ppm.

Who benefits the most?

Studies have shown that most anyone can benefit from added dental protection by fluoride, but the biggest benefits are seen in people who:

  • Snack frequently throughout the day
  • Have poor dental hygiene
  • Are fearful of visiting the dentist
  • Are under-insured or uninsured, and/or have little or no access to a dentist
  • Consume high amounts of sugars and/or carbohydrates
  • Have had extensive dental work performed such as bridges, crowns, braces, or other restorative dental procedures
  • Already have a history of tooth decay or cavities

Most public health authorities and dental associations recommend that both children and adults receive added fluoride as a preventive against tooth decay. Using fluoride is especially effective in children, as it has a demonstrable effect on the structure of developing enamel, particularly in children under the age of 7.


Fluoride is most commonly used as an additive to drinking water in many countries, and is also a star ingredient in the following dental care products:

  • Toothpaste
  • Cements and fillings
  • Gels and mouthwashes
  • Varnishes
  • Some brands of floss
  • Fluoride supplements, recommended in areas where drinking water is not fluoridated

You can also find fluoride in non-dental sources, including:

  • Drugs containing perfluorinated compounds, or PFCs
  • Foods and beverages made with fluoridated water
  • Pesticides
  • Waterproof and stain-resistant items made with PFCs

Excessive fluoride exposure may result from:

  • Public water fluoridation
  • Drinking fresh water in a geographical area that has a naturally occurring high concentration of fluoride, such as southern Asia, the eastern Mediterranean, and Africa.
  • Using fluoridated mouth rinse and toothpaste
  • Drinking untested bottled water
  • Excessive use of fluoride supplements
  • Some foods

Benefits of Fluoride

According to the American Dental Association (ADA), drinking water that is fortified with fluoride is beneficial to communities for the following reasons:

  • It can reduces tooth decay by up to 40 percent
  • Prevents and reduces the incidence of cavities
  • It is a safe and effective method of treating a common health problem
  • It helps people save money on dental treatment
  • It is a naturally derived substance (present in fresh water)

Per the ADA, adding fluoride is like adding vitamin D to milk, adding calcium to orange juice, or fortifying breakfast cereals with B vitamins and folic acid, which are all widely accepted as convenient ways of getting extra vitamins and minerals the human body needs. Studies back up the health benefits of added fluoride. A recent review of multiple studies by Cochrane found that introducing fluoride to water had multiple positive oral health effects on children in particular, including:

  • Children had 35 percent fewer teeth that were decayed, missing, or with cavities that were filled.
  • 15 percent more children did not have any decay found in their baby teeth.
  • 14 percent more children had no decay in their permanent teeth by age 14.

Applying fluoride to children’s teeth (at the dentist) has also been shown to prevent or slow decay. From 2000 to 2014, 449 U.S. communities in 42 states voted to either keep or embrace fluoridation to their municipal water supply.

Side effects

Possible effects of excessive fluoride intake may include:

  • Teeth discoloration
  • Damage to bone or joints

More details about these and other possible side effects can be found under the “Risks” section.

Pros and Cons

The ADA supports the use of fluoride:

  • If used correctly and in the right amounts, fluoride helps prevent or slow dental decay in people of all ages.
  • Adding fluoride is similar to adding essential vitamins and minerals to food and beverages for their health benefits.
  • Using fluoride in water to protect teeth now reduces the need for costly, uncomfortable dental procedures later on in life.
  • Over 100 national and international health or affiliated organizations support the use and promote the benefits of added fluoride.

However, according to the International Academy of Oral Medicine and Toxicology, or IAOMT, widespread use of fluoride poses significant risks to the public. They have argued against its use:

  • Fluoride may be a potential neurotoxin and can be harmful if consumed in large amounts.
  • Too much fluoride can lead to tooth discoloration and more serious bone problems.
  • Fluoride from natural water sources is sufficient to help fight tooth decay for most people.
  • Adding fluoride to water deprives people of the right to choose whether or not they want to consume it.
  • Not everyone needs the same amount of a substance – adding one amount to water and dental products doesn’t take people’s different needs into consideration.
  • We have oversaturated the water supply with fluoride, which may not be safe.
  • Adding fluoride to water and other products may be negatively affecting the environment and could lead to more negative environmental outcomes in the future.


Consuming or using too much fluoride has been linked to a number of health problems:

Dental fluorosis

Dental fluorosis results from exposure to high concentrations of fluoride during childhood, when teeth are still developing. Dental fluorosis causes discoloration of the enamel, which presents as small white streaks or specks on the tooth. These discolorations are not harmful, but their appearance may bother people. You can reduce the incidence of fluorosis in children by supervising children under 6 while they brush their teeth to ensure they do not swallow the toothpaste, and not allowing them to use mouthwashes containing fluoride. If you are currently breastfeeding, consuming fluoride-free water (if possible) or making up infant formula with fluoride-free water can help guard against fluorosis.

Skeletal fluorosis

People can develop a bone disease called skeletal fluorosis as a result of excessive consumption of fluoride. Over the years, skeletal fluorosis can cause pain and damage to the bones and joints by decreasing their elasticity, increasing the risk of fractures. Bone thickening can also occur. Accumulation of excess bone tissue can affect the movement of the joints, impairing mobility.

Thyroid problems

A less common but quite serious condition called hyperparathyroidism can result from consuming too much fluoride. It damages the parathyroid gland, causing it to secrete too many hormones. This imbalance depletes the calcium stores in the bones and increases calcium in the blood, throwing off the blood’s normal concentration and causing symptoms. Low amounts of calcium in the bones can increase the risk of fractures, especially in older women, who are more susceptible to mineral loss.

Neurological problems

A 2014 study on developmental neurotoxicity placed fluoride in the same category as lead, arsenic, toluene, and methylmercury, which are infamous industrial chemicals that can cause serious adverse effects on child development. In addition, a report published in 2017 found a link between prenatal fluoride exposure and decreased cognitive ability in children. The fluoride levels of 299 women were measured during their pregnancies. Researchers then tested the children’s cognitive abilities at age 4, and then again between 6 and 12 years. The higher levels of fluoride the mothers got during pregnancy, the lower the scores their children received on IQ tests.

Other health problems

The IAOMT has also asserted that fluoride use is linked to other serious conditions and many common health problems, including:

  • Acne and other skin disorders
  • Cardiovascular disorders, such as arteriosclerosis, arterial calcification, high blood pressure, heart muscle damage, and heart failure
  • Reproductive disorders, such as decreased fertility and early-onset puberty in young girls
  • Thyroid disorders
  • Disorders affecting the joints and bones, such as osteoarthritis, cancer, and temporomandibular joint disorder (TMJ)
  • Adverse neurological effects and syndromes, such as ADHD

A review of the latest studies in fluoride use, published by the Toxicology Division of the Independent Research Foundation condemned fluoride as an “extreme electron scavenger” with an “insatiable appetite for calcium.” The author of this review called for a comprehensive re-evaluation of the risks versus the benefits of fluoride use.

Fluoride poisoning

Fluoride poisoning can occur from excessive intake of fluoride. The symptoms of a fluoride overdose include:

  • Abdominal pain
  • Excessive saliva
  • Nausea and vomiting
  • Seizures and muscle spasms

Fluoride poisoning often occurs as a side effect of an event such as an industrial fire or explosion that has contaminated the supply of drinking water. You cannot overdose on fluoride from drinking tap water.


There’s two sides to a story, and there is a lot of important information and many facts to consider on both sides of the fluoride debate. Most of the disagreement between proponents and their opponents rests on whether fluoride should be added to drinking water supplies.

According to a German study published in 2000, the rates of tooth decay actually declined in cities that stopped adding fluoride to their water supply. The researchers did note that other factors could have contributed to the change, such as improves access to dental products and dental care, as well as greater awareness of and more positive attitudes towards dental health. Overall, however, their research did link a decrease in cavities to reducing fluoride concentration from 1 ppm to below 0.2 ppm.

What does the WHO say?

According to the World Health Organization (WHO), consuming drinking water that contains more than 1.5 ppm of fluoride can lead to adverse health effects over time. Their recommended upper limit is currently set at 1.5 ppm for this reason.

How much does the EPA allow?

The Environmental Protection Agency (EPA), has set a maximum level of 4 ppm, with a secondary maximum level of 2 ppm. Per the EPA’s rules, levels above 4 ppm can be harmful to human health. The EPA has asked that if you find a level of 2 ppm or above, that you notify them immediately. Because some areas have a water supply that naturally contains a higher level of fluoride, municipal water systems must constantly monitor fluoride levels to make sure it does not go above 4 ppm.


  • There are many substances that can be harmful in large doses but helpful or neutral in small quantities. You should never consume any substance in excessive amounts, and fluoride is no exception – too much can harm you.
  • If you are pregnant, breastfeeding, or planning to become pregnant, you should consider decreasing or eliminating fluoridated water and products containing fluoride for an appropriate amount of time.
  • Consult your dentist before incorporating any fluoride supplements into your diet and/or oral care routine.

If you are concerned about excessive fluoride use or consumption, you can purchase a range of fluoride-free dental care products online, in health food stores, or in some drugstores.