From the Guidelines
Fluoride exposure does not cause thyroid cancer, as extensive research has shown that fluorides do not increase cancer risk. Fluorine is a naturally occurring element that, in its ionic form as fluoride, is used in small amounts in drinking water and dental products to prevent tooth decay. There is no scientific evidence linking appropriate fluoride exposure to thyroid cancer, as stated by the American Cancer Society in their guidelines on nutrition and physical activity for cancer prevention 1. The thyroid does concentrate iodine (not fluorine) for hormone production, and excessive exposure to radioactive iodine can increase thyroid cancer risk. Some people confuse fluoride with other substances or have concerns about its safety, but major health organizations worldwide have extensively studied fluoride and found it safe at recommended levels.
- Key points to consider:
- Fluoride is used to prevent tooth decay and is safe at recommended levels
- There is no scientific evidence linking fluoride exposure to thyroid cancer
- Established risk factors for thyroid cancer include radiation exposure, family history, and iodine deficiency or excess
- Regular medical check-ups are important if you have thyroid concerns, but avoiding fluoride in water or toothpaste is not necessary for thyroid cancer prevention, as supported by the Centers for Disease Control and Prevention's recommendations for using fluoride to prevent and control dental caries 1.
- In terms of morbidity, mortality, and quality of life, it is essential to focus on established risk factors for thyroid cancer and not avoid fluoride in water or toothpaste, as this can lead to unnecessary anxiety and decreased quality of life.
From the Research
Fluoride Exposure and Thyroid Cancer
- There is no direct evidence to suggest that fluoride exposure causes thyroid cancer, as the studies primarily focus on the relationship between fluoride and thyroid function or disease [ 2, 3,4,5,6 ].
- However, some studies have investigated the potential effects of fluoride on thyroid function and disease, which may be relevant to understanding the broader relationship between fluoride and thyroid health.
Effects of Fluoride on Thyroid Function
- A systematic review and dose-response meta-analysis found that high-fluoride drinking water may non-linearly affect thyroid function and increase thyroid-stimulating hormone (TSH) release in children, starting above a threshold of exposure 3.
- Another study found a positive correlation between excess fluoride and hypothyroidism, suggesting a potential link between fluoride exposure and thyroid function 2.
- However, other studies have found no significant association between fluoride exposure and thyroid function or disease, including a study of the Canadian population 4 and a review of the literature on fluorine and thyroid gland function 5.
Fluoride and Thyroid Disease
- Some studies have suggested a positive association between fluoride exposure and certain thyroid diseases, such as goiter and hypothyroidism 3, 6.
- However, the evidence is not consistent, and more research is needed to fully understand the potential relationship between fluoride and thyroid disease.
Animal Studies
- Animal studies have investigated the effects of excess fluoride and iodide on thyroid function and morphology, with some findings suggesting that fluoride can promote specific changes in the function and morphology of the thyroid, either alone or in combination with iodide 6.