Minute investigates: is fluoride bad for your health?

Have you received videos, messages and texts talking about fluoride being bad for your health?

If so, be aware that many of them may contain false or inaccurate information about this substance.

The truth is that there are risks related to excessive fluoride consumption, but, contrary to what many people believe, none of them has to do with the reduction of IQ or effects on memory and cognition.

Read the following text to understand more about fluoride, how it started to be used and what we know so far about the benefits and harms of its consumption

What is fluoride?

Fluorine is nothing more than a natural mineral found in different regions of the planet Earth. It is found in abundance in the sea and in minerals, among which we can highlight fluorite (CaF2), fluorapatite (Ca5 (PO4) 3F) and cryolite (Na3AIF6).

It can be found naturally:

  • In the water;
  • Not only;
  • In plants;
  • On stones;
  • No ar.

The substance can be used to control cavities and is present both in treated water from different regions of Brazil and in products such as toothpaste.

Why did they start adding fluoride to the water?

In the 1930s and early 1940s, the US National Institute of Health published several epidemiological studies suggesting that a fluoride concentration of about 1mg / L could substantially decrease the number of cavities in residents.

Until that time, there were no other studies that demonstrated negative effects of fluoride, even in areas where the concentration of fluoride in water was as high as 8mg / L.

For this reason, it was decided to test the hypothesis that adding fluoride to the water would reduce the number of cavities in the population.

Thus, the substance began to be added to the water in an experimental way in 1945, in Grand Rapids, Michigan, in the United States.

The results, published in 1950, showed that the incidence of caries in the population has decreased significantly.

Because of these results, water fluoridation has become an official US policy, being adopted in much of the country.

According to Biochemistry and Conformity Assessment Manager of the Companhia de Saneamento do Paraná (Sanepar), Cynthia Correia Malaghini, in Brazil, the first capital in the country to receive the fluoridation benefit was Curitiba.

“It started here on October 20, 1958, at the Tarumã treatment plant, which was the first in Paraná. From that, in the 1960s, 5 more cities started to have water fluoridation. It started in Cornélio Procópio, then in União da Vitória, Jacarezinho and Umuarama. ”

It was only in 1974, during the government of Ernesto Geisel, that the fluoridation of public water supply became mandatory.

How fluoride fights cavities

According to Dr. Eduardo Karam, dental surgeon, specialist and master in pediatric dentistry and doctor in stomatology, member of the Paraná Dental Association and Professor at PUC-PR, fluorine acts topically, not systemically.

This means that, in order to take effect, the substance simply needs to come into contact with the teeth, unlike other drugs, which need to enter the bloodstream.

“There are some medical colleagues who say that fluoride kills bacteria. No. This is not the purpose of fluoride, it is not an antibacterial agent. Fluorine acts in a process of remineralization, it is a purely biochemical action.

According to Dr Eduardo, for fluoride to have antibacterial action, it would have to be used in high concentrations, only in very specific cases and with topical use, which is definitely not the case for water supply.

In explaining how fluoride works, Dr. Eduardo defines caries as the loss of minerals from the teeth.

“Thus, fluoride sequesters these lost minerals, such as calcium, ‘hindering’ the demineralization process promoted by caries. We can even say that he is doing a remineralization process. ”

The doctor explains that even lesions caused by caries in the early stages can be inactivated by the effect of fluoride, independent of the bacteria and it will be removed by other means, by the toothbrush, the dental floss, but not by fluoride .

Read more: What is oral health? Know your importance and care tips

Arguments in favor of fluoridation

Since it was implemented, fluoridation has been advocated by the scientific community and government official bodies. Here are some entities around the world that are in favor of water fluoridation:

  • Academy of General Dentistry (Academy of General Dentistry);
  • Academia Americana de Medicina Familiar (American Academy of Family Physicians);
  • American Dental Association;
  • Academia Americana de Pediatria (American Academy of Pediatrics);
  • American Association of Public Health (American Association of Public Health);
  • American Council of Science and Health (American Council of Science and Health);
  • Federation of American Teachers (American Federation of Teachers);
  • American Medical Association;
  • American Public Health Association;
  • American Society for Clinical Nutrition (American Society for Clinical Nutrition);
  • Australian Dental Association;
  • British Dental Health Foundation;
  • British Medical Association;
  • Canadian Dental Association;
  • Canadian Public Health Association;
  • Centers for Disease Control and Prevention (Centers for Disease Control and Prevention – CDC).

All of these associations, foundations and collectives have several arguments in favor of the practice. Check out some of them:

Prevents tooth decay

Proponents of water fluoridation argue that this is the most effective way to prevent tooth decay.

Even the Center for Disease Control and Prevention (CDC) has already elected fluoridation of community water as the tenth greatest public health achievement of the 20th century.

Protects the population from cavities

Studies by the American Dental Association have shown that water fluoridation in communities prevents at least 25% of cavities in children and adults.

This occurs even in areas where access to other fluoride sources is easier (places where toothpaste is widely used).

It is safe and effective

More than 100 health organizations in the United States, many of them mentioned above, recognize the effectiveness and safety of fluoridation for preventing cavities and dental problems.

It’s economical

Treating the population through fluoridation is cheaper than offering dental treatments to every person who has problems that can be avoided with a lack of fluoride.

The estimate is that in most US cities, every $ 1 invested in the practice saves, on average, $ 38 in dental care costs.

It’s natural

Fluoride is naturally present in rivers, lakes, groundwater and in the oceans. Fluoridation only adjusts the amounts of the substance present in the water to be consumed in order to prevent the appearance of cavities.

For those in favor of fluoridation, the practice is similar to adding vitamins and other nutrients to foods and drinks – an example is the addition of vitamin D to milk, the addition of calcium to orange juice and the addition of folic acid to bread.

Arguments against fluoridation

Although official bodies, such as the CDC, recognize that fluoridation is important to maintain the oral health of populations, there are several groups that resist the idea of ​​adding fluoride to water.

To address the issue in a more organized manner, we will focus on the arguments used by the Fluoride Action Network (FAN), an American organization that challenges the effectiveness and safety of water fluoridation.

FAN lists, on its website, several reasons why water fluoridation is no longer carried out by government agencies. Check out:

Fluoridation causes dental and bone fluorosis

Dental fluorosis is a discoloration of the teeth caused by excessive fluoride intake. This statement is reiterated by a study done in 2006 by the US National Research Council (NRC).

Fluoridation may increase the risk of bone fractures

According to the same study by the NRC, water fluoridation can increase the risk of bone fractures in adults and possibly skeletal fluorosis, a disease that causes joint stiffness.

Excess fluoride in the body can cause serious health problems

The same NRC report also found that excess fluoride in the body can be harmful to health and can cause problems such as bone cancer , as well as damage to the brain and thyroid.

Is fluoride good or bad?

As with all other substances on planet Earth, the answer is: it depends .

According to the pediatric dentist, Dr. Eduardo Karam, everything depends on the dose.

“ Fluorine is a chemical element and all chemical elements can be ‘good’ or not. The truth is that the difference between the poison and the medicine is the dosage. The same element can be a medicine or a poison. And fluorine is no different. 

The same opinion is shared by Cynthia Magahlini, who says that “ fluorine is only good within limits. If you exceed the permitted limit [by the international technical standards defined by WHO] it can cause an overload ” .

Biochemistry explains that there is a whole calculation taking into account the other sources of fluoride, such as toothpaste and food (such as crackers), made in the treatment plants before the process was started just to avoid overloads.

“We carry out daily analyzes at the treatment plants. Depending on the situation, these analyzes are made every hour to check that this fluorine is in a minimum condition. ”

The control is so thorough, explains Cynthia, that the fluoride concentration in the water should vary depending on the temperature of the environment.

In Paraná, for example, one works with a concentration of 0.6mg / L or 1.1mg / L depending on the ambient temperature. In the northeast, on the other hand, the concentrations used are lower, as people tend to drink more water.

According to the manager of Sanepar, this is done to avoid health problems, as prolonged consumption of water with a concentration above 2mg / L can cause fluorosis, which is the accumulation of fluoride in bones and teeth.

Perhaps it is for this reason that the controversy surrounding fluorine has existed for so long.

Dr. Eduardo Karam himself reveals that he has heard “strange conversations” about fluoride since his academic training. “Since I did dentistry, more than 30 years ago, this issue has been talked about.”

Even so, the dental surgeon remains optimistic. “The more controversial there is, I think it is a better opportunity for us to clarify to the population.”

This optimism, however, does not exempt him from being categorical by stating that “fluorine is beneficial in the water supply. I would say it is the best preventive agent. It is even better than the dentists themselves, because it alone reduces the prevalence of caries by more than 50%. ”

What can we conclude?

After researching the subject and consulting experts, we can say that fluoride in the water supply is not harmful, except in cases where there is a concentration higher than that recommended by international bodies.

The claims that fluoride in the drinking water would be a risk, then, cannot be sustained. After all, it is as Dr. Eduardo Karam told me:

“Do you think that the main entities responsible for health, including WHO, would not all have taken action if there were problems in the use of fluoride in dentistry?”

It is a valid question and should be asked by those who, even with all the explanations, are still not convinced of the safety of fluoride.

But even so, it is possible that doubts may arise regarding the science behind the use of fluoride. For those who raise this question, Dr. Eduardo’s speech is worth again:

“Science is evolving. It is dynamic. It may be that 15 years from now we will change our position, but today we can safely say that fluoride has benefits in relation to the prevalence and incidence of caries in all places where it is well administered. ”


Today you learned more about fluoride and answered your questions about the safety of this substance in public water supply.

If you liked it, send this text to that friend who is spreading false news about this subject.

More texts investigating the veracity of statements about health can be found in the Minuto Investiga, by Hickey solution!

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