Does Fluoride Decrease Testosterone?
Discussing fluoride's influence on testosterone
Regulatory authorities in many nations have defined “safe limits” for fluoride exposure in drinking water and other sources to prevent dental cavities while reducing potential health hazards. These restrictions are coming into question as more independent research is being published. The defined limitations are designed to keep fluoride exposure at acceptable levels that don't have a negative impact on health, including testosterone levels.
Science has looked into the connection between fluoride and testosterone. The hormone testosterone is essential for the growth and operation of the male reproductive system. It also affects muscle strength, overall stamina, and sleep cycles. Here is a summary of studies that looked into the possibility that exposure to fluoride could affect testosterone levels:
Numerous research on animals has investigated how fluoride affects testosterone levels. Some of this research found that animals exposed to high fluoride levels, notably rodents, had lower testosterone levels, like this 2017 study from A & Khan where they found a “significant decrease in the serum (p<0.01) and testis (p<0.0001) levels of testosterone” in male rats. (A et al., 2017) Although critics point out that some of these studies used fluoride levels greater than the World Health Organization (WHO) regulatory limit of 1.5 mg/L (ppm) (The United States EPA top limit is 4mg/L), they do not consider everyday exposures, including “water, air, food, and medication, as well as cosmetic and industrial products. For instance, high amounts of fluoride have been reported in such different foods and beverages as tea (4.97 ppm), sodas (0.28 ppm), juices (0.36 ppm), canned fish (4.57 ppm), shellfish (3.36 ppm), and cooked wheat cereals (1.02 ppm) (ATSDR, 2001).” (Yilmaz et al., 2018) Due to criticism of studies using higher than 1.5mgL, Yilmas et al. ran their study using lower rates. Still, they found, “The data demonstrate that fluoride downregulates the transcription factors involved in [steroidogenesis] by reducing testosterone and cAMP levels.” (Yilmaz et al., 2018) In other words, fluoride decreases testosterone production.
Liu et al. present an example of the use of higher fluoride levels and note in their human research paper on delayed pubescence, “U.S. National Research Council (NRC) review on fluoride toxicity indicated that high fluoride levels in drinking water (≥4 ppm) are associated with increased risk of enamel fluorosis, bone fractures, and joint pain” Liu et al., 2019)
Using some very old data dating back to the 1940s, the regulatory agencies (EPA, FDA, ADA, etc.) state that fluoride is beneficial, especially in preventing dental cavities. Plenty of research after 2016 is tracking and proving the connection between fluoride and multiple health issues; testosterone is just one. It's significant to note that research examining the association between fluoride and testosterone has limitations. Accurately quantifying fluoride exposure levels is difficult. And these studies are not compounded studies combining multiple exposure points, as mentioned in the Yilmaz paper. Skin is the largest organ in the body and is able to absorb materials, such as water, that contain chlorine and fluoride. Think of showers, baths, drinking water, laundry, and washing hands. These everyday exposures are just from water. Add to that all the others, and the levels we are exposed to are much higher than 1.5mg/L. Furthermore, it might be challenging to demonstrate a straight cause-and-effect link since confounding variables, including age, nutrition, lifestyle, and other environmental exposures, can affect testosterone levels.
In conclusion, the connection between testosterone levels and fluoride exposure is complicated. Agencies like the CDC, EPA, FDA, and the American Dental Association (ADA) contend that fluoride benefits teeth. This may change with the ongoing trial contesting that it is a toxin. Perhaps, in the near future, fluoride will be removed from drinking water. Perhaps.
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Resources
Duan L, Zhu J, Wang K, Zhou G, Yang Y, Cui L, Huang H, Cheng X, Ba Y. Does Fluoride Affect Serum Testosterone and Androgen Binding Protein with Age-Specificity? A Population-Based Cross-Sectional Study in Chinese Male Farmers. Biol Trace Elem Res. 2016 Dec;174(2):294-299. doi: 10.1007/s12011-016-0726-z. Epub 2016 May 6. PMID: 27154732.
EPA. Questions & Answers on Fluoride pamphlet. 2015. https://www.epa.gov/sites/default/files/2015-10/documents/2011_fluoride_questionsanswers.pdf
Liu, Y., Téllez-Rojo, M., Hu, H. et al. Fluoride exposure and pubertal development in children living in Mexico City. Environ Health 18, 26 (2019). https://doi.org/10.1186/s12940-019-0465-7.
Dibyendu, Ray1,; Tiasa, Chatterjee1; Das, Monalisha1; Pradip, Panda2; Sandip, Mukherjee1. Folic acid protects against fluoride-induced oxidative stress and testicular damage in rats. Asian Pacific Journal of Reproduction 10(6):p 274-283, November 2021. | DOI: 10.4103/2305-0500.331265. https://journals.lww.com/apjr/Fulltext/2021/10060/Folic_acid_protects_against_fluoride_induced.5.aspx
A, Shashi, and I. Khan. “EFFICACY OF BOERHAAVIA DIFFUSA L. ON DISRUPTION OF GONADOTROPINS AND TESTOSTERONE IN FLUORIDE INTOXICATED MALE RATS.“ Asian Journal of Pharmaceutical and Clinical Research, vol. 10, no. 12. Dec. 2017, pp. 68-73, doi:10.22159/ajpcr.2017.v10i12.20604. https://journals.innovareacademics.in/index.php/ajpcr/article/view/20604
Yilmaz, Banu Orta , Ahu Korkut, Melike Erkan. Sodium fluoride disrupts testosterone biosynthesis by affecting the steroidogenic pathway in TM3 Leydig cells. Chemosphere. Volume 212. 2018. Pages 447-455. ISSN 0045-6535. https://doi.org/10.1016/j.chemosphere.2018.08.112.(https://www.sciencedirect.com/science/article/pii/S0045653518315881)
If you’re interested in reading more on this subject, here is a link to a list of papers:
https://consultations.nhmrc.gov.au/public_consultations/submissions/WFD/6173.html