Hi Reader,

in light of recent discussions, particularly as President Trump takes office and his Health Secretary brings fluoride back into focus, it is time to examine this topic that has seen a resurgence in debate. Fluoride, a mineral salt often associated with dental health, polarizes scientists, medical professionals, and the public alike. But what does the science actually say? Let us delve into the facts, dispel myths, and uncover the truth about fluoride.

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Fluoride makes you dumb!
Does it ?

What Is Fluoride?

Fluoride is the ionic form of the element fluorine (essentially the salt of fluorine), found abundantly in nature. It is present in rocks, water, and even many foods. About 99% of the fluoride absorbed by our bodies is stored in calcified tissues like teeth and bones, making it an essential player in the human body—at least in moderate amounts.

The History of Fluoride in Medicine

The beneficial effects of fluoride on dental health were first discovered in the 19th century, sparked by an unusual observation in Colorado. In one region, residents exhibited a peculiar brown discoloration of their teeth, termed the "Colorado brown stain." Despite the color, their teeth were unusually resistant to decay. This led researchers to investigate environmental factors, and the high fluoride levels in the local water supply were identified as the cause.

Building on these findings, the German physician Carl Eckardt proposed in 1874 the use of fluoride tablets to prevent dental issues. A landmark experiment in 1945 in Grand Rapids, Michigan (USA) further cemented fluoride’s benefits. By adding fluoride to the local water supply, researchers observed a significant reduction in cavities among the population.

Since the 1960s, fluoride has been routinely added to water supplies in many countries, including the United States. In Europe, however, fluoride is more commonly added to milk or salt rather than water.

Why Is Fluoride Important?

Fluoride plays a key role in protecting teeth. It strengthens enamel by preventing demineralization and promoting remineralization. Fluoride reacts with the apatite in enamel to form fluorapatite, an extremely durable protective layer resistant to acids. Additionally, fluoride inhibits the growth of cavity-causing bacteria and indirectly supports both dental and bone health.

A 2019 Cochrane meta-analysis of 96 studies found that fluoride toothpaste provides significantly better protection against cavities than fluoride-free alternatives, which showed no benefits beyond cleaning and a placebo effect.

How Is Fluoride Absorbed?

Most fluoride intake comes from drinking water, food, and toothpaste. Initially, it works locally on the tooth enamel. Additionally, fluoride is absorbed in the small intestine. About half of it is excreted through the kidneys, while the rest binds to bones and teeth, where it forms the more resilient fluorapatite.

Side Effects and Risks

As with many substances, the dosage of fluoride determines its effects. In Europe, the recommended intake is 0.05 mg per kilogram of body weight daily.

Exceeding 5–6 mg per day can lead to dental fluorosis, visible as white or brown spots on teeth. If combined with iodine deficiency, there is a risk of triggering or exacerbating hypothyroidism. Higher doses (above 10 mg per day) can cause skeletal fluorosis, resulting in hardened but brittle bones, joint stiffness, and kidney damage.

Chronic exposure to more than 20 mg per day can lead to fluoride toxicity, with symptoms such as coughing, shortness of breath, and cardiac complications.

One contentious topic is the potential for fluoride to cause neural damage or developmental issues in children. Concerns have arisen about whether prolonged exposure to high fluoride levels during development might reduce intelligence.

A meta-analysis of eight cohort studies found no clear correlation between children’s IQ and fluoride levels in artificially fluoridated water supplies in the U.S.

However, studies in China and India identified a link between naturally high fluoride levels in groundwater (3.7 mg/L) and lower IQ scores compared to areas with lower fluoride levels (0.7 mg/L). No differences were found between regions with low (0.9 mg/L) and very low (0.3 mg/L) fluoride levels.

Another Chinese meta-analysis of 26 observational studies indicated a linear relationship between water fluoride levels and IQ. However, these studies are criticized for poor data quality and failing to account for variables like education, socioeconomic status, and exposure to other environmental toxins.

Such alarming fluoride concentrations far exceed levels typically found in Europe, and the methodological flaws of these studies warrant caution in interpreting their findings.

Conclusion

The benefits of fluoride for dental health are well-established. It effectively prevents cavities by strengthening enamel and inhibiting bacterial growth. Fluoride toothpaste is a reliable tool for maintaining good dental health in Germany and Europe, where water fluoridation is unnecessary.

However, moderation is key: use toothpaste sparingly (pea-sized amounts) and avoid swallowing it. Toothpaste fluoride content is usually labeled in parts per million (ppm), with 1,000 ppm equating to approximately 1 mg/mL.

Although fluoride overdoses are rare in Europe, prevention remains the best strategy. By staying informed and practicing mindful fluoride use, you can safeguard your health and enjoy its proven benefits.

Sources:

1. Featherstone JD. Prevention and reversal of dental caries: role of low level fluoride. Community Dent Oral Epidemiol. 1999 Feb;27(1):31-40. doi: 10.1111/j.1600-0528.1999.tb01989.x. PMID: 10086924.

2. Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database Syst Rev. 2019 Mar 4;3(3):CD007868. doi: 10.1002/14651858.CD007868.pub3. PMID: 30829399; PMCID: PMC6398117.

3. Berger MM, Shenkin A, Schweinlin A, Amrein K, Augsburger M, Biesalski HK, Bischoff SC, Casaer MP, Gundogan K, Lepp HL, de Man AME, Muscogiuri G, Pietka M, Pironi L, Rezzi S, Cuerda C. ESPEN micronutrient guideline. Clin Nutr. 2022 Jun;41(6):1357-1424. doi: 10.1016/j.clnu.2022.02.015. Epub 2022 Feb 26. Erratum in: Clin Nutr. 2024 Apr;43(4):1024. doi: 10.1016/j.clnu.2024.03.004. PMID: 35365361.

4. Duan Q, Jiao J, Chen X, Wang X. Association between water fluoride and the level of children's intelligence: a dose-response meta-analysis. Public Health. 2018 Jan;154:87-97. doi: 10.1016/j.puhe.2017.08.013. Epub 2017 Dec 22. PMID: 29220711.

5. Kumar JV, Moss ME, Liu H, Fisher-Owens S. Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation. Public Health. 2023 Jun;219:73-84. doi: 10.1016/j.puhe.2023.03.011. Epub 2023 Apr 28. PMID: 37120936

6. Chaitanya, Nallan CSK; Karunakar, P1; Allam, Neeharika Satya Jyothi; Priya, M Hima; Alekhya, B; Nauseen, Shaguftha. A Systematic Analysis on Possibility of Water Fluoridation Causing Hypothyroidism. Indian Journal of Dental Research 29(3):p 358-363, May–Jun 2018. | DOI: 10.4103/ijdr.IJDR_505_16

7. Peckham S, Lowery D, Spencer S; Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water; J Epidemiol Community Health 2015;69:619-624.

8. Eckardt [sic] (1874). "Kali fluoratum zur Erhaltung der Zähne". Der Praktische Arzt (in German). 15 (3): 69–70

9. Dean HT, Arnold FA, Jay P, Knutson JW (October 1950). "Studies on mass control of dental caries through fluoridation of the public water supply". Public Health Reports. 65 (43): 1403–1408. doi:10.2307/4587515.

Stay curious and healthy! If you have any questions or would like to learn more about specific topics, feel free to reach out. I look forward to hearing from you.

Warm regards,

Karsten