Fluoride (F)

What is fluoride?

Fluoride is a mineral that helps us maintain healthy teeth and bones. It is a form of the chemical element fluorine. We cannot produce fluoride in our bodies, so we instead get it through our diet. Fluoride is not technically an essential nutrient (meaning we can survive without it), but it is still important for our health.

Why we need it

Fluoride helps protect our teeth against cavities. It does so by reducing demineralization, which is a process by which acid can break down tooth enamel. Specifically, when fluoride is incorporated into tooth enamel, it forms fluorapatite, a crystalline substance that provides resistance against demineralization.¹ In other words, fluoride helps prevent the breakdown of tooth enamel, thus protecting against cavities.

Fluoride also supports our bone health. This is because fluoride can stimulate osteoblasts, which are cells that build new bone, and it can inhibit osteoclasts, which are cells that break down bone.² Thus, fluoride not only helps us form new bone, but it helps us maintain strong bones over time.

Where it’s found

Most of the fluoride we consume is from water. This is because fluoride is often added to drinking water as a public health measure (to prevent dental caries). Fluoride is also found in black tea, since these tea leaves have the ability to take up fluoride from soil. Some foods contain fluoride, but in small amounts. These include canned fish, raisins, potatoes, and oatmeal. We can also get fluoride topically, from fluoride-containing toothpastes or mouth rinses.

Daily requirements

There is not enough evidence to establish a firm dietary recommendation (i.e., a Recommended Dietary Allowance) for fluoride, so an Adequate Intake (AI) is used instead. The AI is the daily amount of a nutrient that is assumed to be sufficient for most people.

The AI for fluoride is 0.7-1 milligrams (mg) for children aged 1-8 years, 2 mg for children aged 9-13 years, 3 mg for adolescents aged 14-18 years, 3 mg for women over the age of 19, and 4 mg for men over the age of 19.³

Fluoride deficiency

Not getting enough of fluoride may increase your risk of cavities and tooth decay. This is because when fluoride is not present in adequate amounts, demineralization (i.e., the breakdown of tooth enamel) may become more likely. Fluoride deficiency may negatively affect bone health as well, making the bones more brittle and susceptible to fractures. These consequences are seen in communities where fluoride is not added to drinking water. For example, the risk of dental caries has been shown to be significantly higher among non-fluoridated areas compared to fluoridated areas.⁴

Can you get too much fluoride?

Excessive fluoride consumption can be harmful. Acute (short term) fluoride toxicity can cause nausea and vomiting, as well as more serious issues like seizures or heart arrhythmia. Chronic (long term) fluoride toxicity, also known as fluorosis, can cause issues with our bones and teeth. For example, fluorosis can cause our joints to become stiff and painful, and can increase our risk of bone fractures.⁴ Fluorosis can also cause visible changes in our teeth, including white streaks or brown staining.⁵

To prevent toxicity, a Tolerable Upper Intake Level (UL) has been established for fluoride. The UL for fluoride, which represents the maximum daily amount that is considered safe, is 1.3 mg for children aged 1-3 years, 2.2 mg for children aged 4-8 years, and 10 mg for adults and children over the age of 9.³

Fun facts

Compared to all the other vitamins and minerals we get through our diet, fluoride is unique in that we don’t get much from food. In fact, it’s estimated that 75% of our fluoride intake comes from water and processed beverages (e.g., soda and fruit juice).⁶

Fluoridation (the addition of fluoride to water) is considered one of the greatest public health achievements. Specifically, it was recognized by the Centers for Disease Control as one of the “Ten Great Public Health Achievements” of the twentieth century.⁷