March 30th, 2011
By: Melissa Keith
Last year Health Canada released Fluoride in Drinking Water, a document for public inspection and comment, prepared by the Federal-Provincial-Territorial Committee on Drinking Water.
A panel of six experts, four of them dentists, investigated fluoride exposure data with the intent of “revising the current drinking-water guideline” for Canada, while explicitly stating that their objective was not to dictate municipal fluoridation practices.
Fluoridated water is a tough mouthful to swallow for the increasing number of Canadians questioning its impact on their bodies and the environment. Critics have questioned the lengthy report on multiple fronts, including failure to rigorously assess the role of fluoride in a globally pervasive health condition—thyroid disease.
The Health Canada study did not seriously consider thyroid health when it put forward a maximum acceptable concentration (MAC) level of 1.5 mg of fluoride per litre of tap water, according to a response from Carole Clinch, research coordinator with People for Safe Drinking Water.
Why focus on thyroid function?
For starters, the thyroid gland is a repository where fluoride accumulates throughout one’s lifetime.
Fluoride is a very small, chemically reactive particle that tends to displace other minerals in certain storage sites within the body. For this reason, it has been used in osteoporosis treatment—fluoride reinforces bone where calcium has been depleted—and dentistry to replace minerals lost from the teeth.
It should be remembered that the World Health Organization (WHO) treats fluoride more like a drug than an essential nutrient. Fluoridation of a municipal water supply is, in effect, administration of a substance that can create “chemical hazards with clearly defined health effects” for all users of that water, according to WHO.
Unless reverse osmosis, distillation, or activated alumina systems are used, you are not able to remove the fluoride. As Paul Connett, PhD, professor emeritus of environmental chemistry at St. Lawrence University in Canton, New York, declares in his critique of Health Canada’s proposed MAC level for fluoride, “Once fluoride has been added to the water it is no longer possible to control the dose that people get. There will be literally millions of people who will get a higher dose of fluoride drinking water at 0.8 ppm [parts per million] than people would get drinking water at 1.5 ppm.”
How fluoride affects the thyroid
Evidence that fluoride accumulates in the thyroid dates back to the early 1900s, where its presence in the glandular tissue first came to light because of obvious goitres (swollen, enlarged thyroid glands).
In the thyroid gland, fluoride can prevent iodine from playing its proper role in synthesizing two hormones critical for normal metabolic activity throughout the body—T3 (triiodothyronine) and T4 (thyroxine).
The names of these hormones allude to the number of iodide particles the thyroid needs to build them. When fluoride—a more reactive substance from the same chemical family as iodine (the halides)—enters the picture, it can interfere with the T3 and T4 manufacture by blocking iodide receptors.