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Fluoride in the body
Last reviewed: 03.07.2025
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Fluorine is the 17th element in the periodic table of chemical elements. Its name comes from the Latin word "fluorescence" - flow. Fluorine is naturally found in many sources - in water, food, soil and several minerals such as fluorite and fluorapatite. But it can also be synthesized in the laboratory, where fluorine is added to drinking water and used in various chemical products. When is fluorine good for the body, and when does it become harmful?
What increases the amount of fluoride?
The concentration of fluorine in our food products increases significantly with the addition of superphosphate to the soil - a fertilizer that contains significant concentrations of fluorine (1-3%). A recent study shows that due to the use of large amounts of phosphorus fertilizers, plants absorb excess amounts of fluorine.
The level of fluoride in food depends on the fluoride content of water used in soil preparation or cultivation.
The concentration of fluoride in unwashed or unprocessed products grown in the vicinity of industrial sources (emissions) may be higher than in the same products grown in ecologically clean areas. Therefore, when buying products, pay attention to their labeling. Now there are special stores of eco-products that are healthier than products of unknown origin.
Who needs fluoride?
Many doctors recommend a certain level of fluoride for both children and adults. Children need fluoride to protect their teeth while they are forming. Adults need fluoride to protect their teeth from decay.
Fluoride treatment is needed for people in such circumstances
- Caries
- Lack of or limited access to dentists
- Poor oral hygiene
- A diet high in sugar or carbohydrates
- Smoking
- Alcohol abuse
- Braces, crowns, bridges and other dental restoration objects
- Lack of saliva or dry mouth
[ Sources of fluoride in the body
Fluoride can enter the body with food. If you eat food containing fluoride (such as meat, fish, eggs, tea and green salad leaves), fluoride enters the blood, then it is absorbed by the teeth and bones.
Most people have access to fluoride to strengthen their tooth enamel, either through treated drinking water or through oral hygiene products such as toothpaste and mouthwash.
Fluoride can also be applied directly to your teeth at the dentist's office. Teeth absorb fluoride well and it stays in your mouth for several hours.
Absorption of fluoride by the body
When ingested, fluoride enters the bloodstream and is retained mainly in the stomach and intestines. Its absorption depends on its solubility in water and the dose consumed. Soluble fluorides are almost completely absorbed by the walls of the gastrointestinal tract, but the degree of fluoride absorption can be reduced by elements such as aluminum, phosphorus, magnesium, or calcium. Fluoride can be absorbed partially or completely from the respiratory tract as a gas or in solid form (e.g., toothpaste).
Fluoride is rapidly distributed from tissues through the systemic circulation to extracellular fluid, but in humans and laboratory animals about 99% of fluoride accumulates in bones and teeth.
In a pregnant woman, fluoride crosses the placenta and is transferred from mother to fetus.
The concentration of fluoride in bones depends on age, gender and bone condition.
Its absorption is also determined by the efficiency of the kidneys, which excrete fluoride.
Fluoride is excreted from the body mainly through urine. In children, about 80-90% of the fluoride dose is retained, while in adults this figure is about 60%.
Daily dose of fluoride
It ranges from 1.5 to 2 mg per day.
What are the benefits of fluoride?
Fluoride protects teeth from decay and their enamel from damage. When bacteria in the mouth interact with sugars, acid is produced that can break down tooth enamel and damage teeth. This process is called demineralization. When teeth are already damaged by acid, fluoride accumulates in the demineralized areas and begins the process of rebuilding the enamel - a process called remineralization. Fluoride is very useful in preventing decay and strengthening teeth, but its effectiveness is much weaker if the tooth cavity is already damaged.
Why is the effect of fluoride so controversial?
Although scientific studies confirm the benefits of fluoride in preventing tooth decay, scientists have concerns about its safety. The increase in dental fluorosis due to elevated fluoride concentrations in water that exceed the optimal level requires immediate cessation of fluoridated drinking water. Some scientists believe that fluoride treatment is unnecessary.
Adding fluoride to drinking water was first introduced in the 1940s to prevent tooth decay. Studies have shown that fluoride causes dental fluorosis in 10% of the population.
Scientific studies have also linked fluoride to increased risk of cancer (especially bone cancer), gene mutations, and reproductive neurotoxicity (such as hyper-depression). In 1999, the EPA's Union of Scientists headquarters took a position against fluoridation of drinking water.
According to the EPA, fluoride is used to fluoridate water as an "unapproved drug." To use this drug correctly, you need to understand how optimal its doses are. Since fluoride is already present in many foods and drinks, scientists estimate that the total daily dose of fluoride as a pharmaceutical drug may be excessive. Research shows that, according to the American Dental Association, artificial fluoridation is not necessary for humans, since we already receive 300% or more of the recommended daily dose of fluoride from food and brushing our teeth.
Excess fluoride
Proper use of fluoride is considered safe and effective in preventing tooth decay. However, high levels of fluoride can cause harm to a person when exposed to teeth over a long period of time. For example, too much fluoride can cause dental fluorosis - a change in enamel color, fragility, and chipping.
More extreme, toxic effects of fluoride can even lead to death if a person consumes too much of the element. Fluoride overdose is possible, for example, if a small child eats an entire pack of toothpaste. And then the following symptoms are evident: nausea, vomiting of blood, diarrhea, abdominal pain, salivation, lacrimation, general weakness, shallow breathing, increased fatigue, convulsions.
In addition, exposure to high concentrations of fluoride leads to weakening of bones and skeletal fluorosis (stiffness and pain in the joints). In high doses, fluoride disrupts collagen synthesis and leads to the destruction of collagen in bones, tendons, muscles, skin, cartilage, lungs, kidneys and trachea, and also leads to early wrinkles on the skin.
At high doses, fluoride disrupts the immune system and causes it to attack the body's own tissues, and also increases the rate of tumor growth in those prone to cancer.
Fluoride can cause allergic reactions in a wide range of chronic diseases, including dermatitis, eczema, and urticaria. Fluoride in large quantities causes birth defects and genetic disorders. Fluoride can worsen kidney disease, diabetes, and hypothyroidism.
How much fluoride is in toothpaste?
Toothpastes and gels for adults typically contain fluoride at concentrations of 1000 to 1500 mcg/g, while hygiene pastes and gels intended for children contain lower levels of fluoride, from 250 to 500 mcg/g.
Mouthwashes for daily home use typically contain 230 to 500 mg fluoride/L, while weekly or biweekly mouthwashes may contain even more fluoride, ranging from 900 to 1000 mg/L. These are all potent sources of fluoride.