Why are we Iodine Deficient?
#1 Likely Reason - Presence of goitrogens that compete with iodine for body's receptors
Goitrogens: fluoride, chlorine and bromine, are excessively present today in our food and water
Fluoride, chlorine and bromine all “beat out” iodine. Atomic weight determines which overpowers the other - fluoride is the overall winner, and iodine the loser.
Goiter-countering iodine used to be added to bread, but now goiter-causing bromate is added instead. From 1960-1980, iodine-containing dough conditioners added 150 mcg of iodine to each slice! But over the past 20 years, food processors have substituted this conditioner with bromate, a goitrogenic substance that easily binds to the thyroid gland's iodine receptors and so inhibits iodine activity and contributes to goiters (Too much bromine can also cause impaired thinking and memory, drowsiness, dizziness and irritability). The substitution of bromine for iodine has resulted in nearly universal deficiency of iodine in the U.S..
Iodide in Table Salt is not very Bioavailable
Iodate in bread is very bioavailable, whereas only 10% of iodide in iodized salt is absorbed:
Pittman, et al, measured serum inorganic iodide levels in two groups of subjects:
✔GROUP 1: after iodization of salt, with an estimated daily intake of 750 mcg iodide, and
✔GROUP 2: after iodization of bread, with a similar average intake of iodates.
The expected mean blood level at equilibrium would be 17.2 mcg/L (750 mcg/43.5 L). The mean values observed by Pittman, et al, were 1.7 mcg/L for subjects after iodization of salt, and 18.7 mcg/L for subjects after iodization of bread.
There is 30,000 times more chloride than iodide in iodized salt (on a molar basis). Chloride competes with iodide for absorption in the intestinal tract. The low bioavailability of iodide in iodized table salt (sodium chloride) has not generally been reported.
Pittman JA, et al. "Changing normal values for thyroidal radioiodine uptake." NEJM, 1969; 280:1431-1434. PubMed
To get enough iodine to provide a maintenance dose for whole-body sufficiency (i.e. ~3mg), you would need to consume over an ounce of salt every day.
✔ Iodized salt contains a mere 0.076 mg of iodine / gram of salt.
✔ Sea salt, soy sauce, and Bragg's liquid amino acids are all salty condiments that contain NO iodine. Contrary to instinctive opinion, sea salt has very little iodide compared to iodized table salt. The concentration of iodide/iodate in the oceans is a very dilute 0.05 PPM (compare this to bromide, which is 1400 times more concentrated).
Only ~50% of Americans use iodized salt. Many people are persuaded to reduce salt intake, usually because of high blood pressure concerns.
Some areas of the US, known as the Goiter Belt, simply have a very low iodine content. This includes mountainous regions, the Mississippi River Valley, the Ohio River Valley, and the Great Lakes regions (e.g. 40% of the people living in Michigan suffered from goiter in the 1930's). Also, over-farming has depleted iodine content in soils previously-rich in iodine. All soil containing granite is poor in iodine. E.g. Vermont. Coastal regions have a richer iodine content than inland (Iodide ions in seawater are oxidized to elemental iodine, which is volatilized by UV into the atmosphere and returned to the soil by rain, completing the cycle)
A Biblical Explanation. After the Great Flood, the receding waters washed away the topsoil with all its elements into the oceans and seas. The new topsoil became deficient in iodine and other essential elements. Mountainous areas became the most iodine-deficient because the receding waters were the most rapid over the steep slopes, eroding deeper into the soil and washing it into the seas.
Toxic metal contamination is now abundant in many places and products. Here's just a few examples:
✔ Mercury in fish. Especially high in large tuna, shark and swordfish;
✔ Mercury leaching from dental fillings
✔ Cadmium from tires (in road dust)
Long-term use of these drugs depletes thyroid and tissue iodine levels. This is associated with increased cancer rates. Fluorescent scanning of the thyroid clearly shows how drug and other medical thyroid therapies deplete the gland and body of critical iodine.
Synthroid or other thyroid-destructive therapies should never be taken without iodine therapy to ensure whole body iodine sufficiency
Lithium can block the release of thyroid hormones from the thyroid gland. Occurs in 5-15% of patients on long term therapy.