Written by Greg Arnold, DC, CSCS. Compared to residents in areas where water samples contained less than 0.3 milligrams of fluoride per liter of water, risk of having hypothyroidism was significantly greater (40%) with fluoride levels were between 0.3 and 0.7 mg/L and 60% greater with fluoride levels greater than 0.7 mg/L.
Hypothyroidism is a condition whereby the thyroid gland, located in the front of the neck surrounding the windpipe, does not produce enough hormones. This can slow down the metabolism, frequently leading to weight gain, fatigue, lethargy, even constipation and decreased quality of life (1). Hypothyroidism is the most common type of gland disorder, affecting about 1 in 22 Americans over the age of 12 (4.6%) (2).
Now a new study out of England (3) suggests excess fluoride intake through water consumption may be adversely affecting thyroid function. Fluoridation of the public water supply was first done in the United States in the 1950s and has been an accepted public dental health intervention (4). A recent Public Health England report concluded that water fluoridation is a safe public health measure (5).
In the study, researchers obtained data on all diagnosed cases of hypothyroidism in 7,935 primary care physician practices in England between April 2012 and March 2013. They then analyzed fluoride concentration in the water supply by taking random samples from chosen consumers’ taps and/or water supply zones based on previous reports of water usage in England (4).
The researchers found that “higher levels of fluoride in drinking water provide a useful contribution for predicting prevalence of hypothyroidism”. Specifically, compared to residents in areas where water samples contained less than 0.3 milligrams of fluoride per liter of water, residents in areas with fluoride levels between 0.3 and 0.7 mg/L had a 40% greater risk of having hypothyroidism while areas with fluoride levels greater than 0.7 mg/L had a 60% greater risk (p < 0.001).
When looking at specific regions of England, they found that practices located in “wholly fluoridated areas” such as an area called the West Midlands were nearly twice as likely to report high hypothyroidism prevalence in comparison to areas whose groundwater had not been fluoridated like Greater Manchester (p < 0.001).
While admitting that their study did not take into account sources of fluoride ingestion other than that in drinking water, as fluoride is found in many dental products and food and drink (5, 6), they believe “drinking water is still the primary source of fluoride in England, particularly in areas with fluoride concentration of 1 mg/L and over” (7).
For the researchers, “hypothyroidism is a major health concern and in addition to other factors—such as iodine deficiency— fluoride exposure should be considered as a contributing factor” and that “The findings of the study raise particular concerns about the validity of community fluoridation as a safe public health measure.”
Source: Peckham, Stephen, David Lowery, and Sarah Spencer. “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.” Journal of epidemiology and community health 69.7 (2015): 619-624.
Click here to read the full text study.
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his website at www.PitchingDoc.com.
References:
- “Hypothyroidism” posted on the National Institutes of Health Website
- Golden SH, Robinson KA, Saldanha I, Anton B, Ladenson PW. Prevalence and incidence of endocrine and metabolic disorders in the United States: a comprehensive review. Journal of Clinical Endocrinology & Metabolism. 2009;94(6):1853–1878
- Peckham 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 Feb 24. pii: jech-2014-204971. doi: 10.1136/jech-2014-204971. [Epub ahead of print]
