Despite public fluoridation being such a heavily debated topic, a 2015 paper out of the Journal of Epidemiology & Community Health represents one of the rare well-designed, -controlled, and -analysed peer-reviewed research studies on the topic.
While it is difficult to manage control groups in the US where over 2/3 of our population consumes fluoridated water, it is much easier in Western Europe where fluoridation is headed towards extinction. This observational study looked at hyperthyroidism prevalence in 2 neighboring cities and the results were not good for fluoride drinkers' thyroids.
"We found that higher levels of fluoride in drinking water provide a useful contribution for predicting prevalence of hypothyroidism. We found that practices located in the West Midlands (a wholly fluoridated area) are nearly twice as likely to report high hypothyroidism prevalence in comparison to Greater Manchester (non-fluoridated area)." (Peckham, 2015)
The writers go on to conclude that Fluoride exposure should be considered a contributing factor to Hyperthyroidism. In the United States, where Fluoride is added to our water without our permission or control, anyone attempting to reduce their risk of Hyperthyroidism should consider a water filter like the REVIVAL Ultra filter that can filter Fluoride.
Science behind the study
If we know that fluoride may be increasing the risk of hyperthyroidism, the logical question to ask is "Why?".
The thyroid gland plays a critical role in the bodies health by regulating its metabolic rate. Because all metabolically active cells require thyroid hormone for proper functioning, thyroid disruption can have a wide range of effects on virtually every system of the body and chemicals that interfere with thyroid function must be treated with great concern. According to the U.S. National Research Council, there is substantial evidence that fluoride exposure can impact thyroid function. Fluoride was historically used as a thyroid suppressant by doctors. The fluoride dose capable of reducing thyroid function was notably low — just 2 to 5 mg per day over several months. This dose is well within the range of what individuals living in fluoridated communities are now estimated to receive on a regular basis. Based on fluoride’s anti-thyroid effects, concerns have arisen about whether current fluoride exposures could be contributing to the increased prevalence of under-active thyroid.
Hypothyroidism entails the thyroid gland failing to produce sufficient quantities of the thyroid hormones, T3 and T4. These hormones are required by all metabolically active cells and their reduced presence produces a range of ill effects, including fatigue, muscle/joint pain, depression, weight gain, menstrual disturbances, impaired fertility, impaired memory, and inability to concentrate. When T3 and T4 levels begin to fall, the pituitary gland responds by increasing production of “Thyroid Stimulating Hormone” (TSH) as a means of getting the thyroid to produce more T3 and T4. The most common thyroid effect associated with fluoride exposure appears to be an increase in TSH levels without the reciprocating increase in T3 and T4.
In short, fluoride is a known thyroid inhibitor. One of the most important functions of the thyroid is to product hormones that spur along the metabolism. When they can't be produced, a cascade of health effects result that compromise our health.
The abstract of the study is available here.