It would be quite a skill to avoid fluoride these days. Most water supplies have it, as do some toothpastes, non-stick pans, and many medications such as Prozac (flouxetine). It is estimated that the average American gets somewhere between 1.6 to 6.6 mg/day of fluoride each day.
What most people don’t know is that fluoride was used through the 1950’s to suppress thyroid function in cases of hyperthyroidism in South America and Europe (1).
The thyroid needs iodine to make a thyroid hormone called T3 (triiodothyronine). Iodine is in a class of minerals called halogens, along with Bromine, Chlorine, and Fluorine, the element of which fluoride is the negative ion. When iodine is low in the body – which the World Health Organization claims effects up to 72% of the world’s population – the other available halogens can uptake into and block the thyroid gland.
Since fluoride has become a ubiquitous part of our food and environment, low iodine levels in the body in combination with excess environmental fluorides may cause fluoride to uptake into the thyroid gland. From there, it may compete with iodine and act as an effective thyroid suppressant, just like it did in the 1950’s.
Research in the fifties showed that all that was needed to suppress the thyroid was just 2-5 mg of fluoride per day for a couple of months (2). Most Americans are easily exposed to these levels, putting the thyroid at risk.
Research has indicated that the current RDA for iodine, at 150 mcg per day, may be too low. The new levels that I reported on in my article, Protect Your Breasts, indicated the need for 3-6mg per day to inhibit toxic estrogens from absorbing into the breast, which may be linked to breast cancer (3).
To help support optimal function of your thyroid, consider limiting fluoride exposure (more to come on this) and adding iodine into your diet as a food or supplement.