Do not become iodine toxic

A follower of the Wheat Belly 10-Day Grain Detox Facebook page posted this concerning comment:

“We have been on the Wheat Belly lifestyle since October 16. We have been taking the supplements and eating right – no cheating. I had a routine doctor visit on October 30th, and they took blood. My results came back showing my thyroid level was elevated. I’ve never had thyroid issues in the past. Is it possible the tri-iodine, 12.5 mg, that I’m taking is effecting my thyroid? Also, my husband has lost over 10 pounds and I had lost 5 and now gained back 3. We are doing the exact same things! It’s a bit frustrating. I have no energy and horrible mental fog. My boss has been very concerned. At this moment I’m wearing a heart monitor because I thought I might be dying!”

In other words, she is taking 12,500 micrograms of iodine, far more than the 350-500 mcg I recommend.

This is a toxic dose, even though there are a number of commercially-available iodine preparations such as Tri-Iodine, Iodoral, and Lugol’s solution, that deliver such large doses. The result of taking this much iodine for even a few weeks is a rise in thyroid stimulating hormone, TSH, that signals hypothyroidism—the thyroid stops producing thyroid hormones. I’ve seen this happen many times in which such high toxic doses of iodine yield TSH values of 12, 20, or 30 mIU/L, values (recall that we aim to keep TSH at 2.0 mIU/L or less) well into the hypothyroid range and are associated with fatigue, feeling cold, weight gain, along with markedly increased risk for heart disease in various forms (coronary disease, congestive heart failure). In short, high doses of iodine yield hypothyroidism and, if not recognized and corrected, can be fatal. It is not clear why such high doses of iodine cause hypothyroidism, but this is an effect that has been observed many times over the past century since iodine’s role in thyroid health has been recognized.

This is why I am very specific about the dose of iodine we use. Unfortunately, there are some doctors and social media conversations in which such high iodine doses are advocated with claims of extravagant results. But note that in these situations iodine status is tracked over time with reduced intake when absorption declines. Also, it makes no sense that a supra physiologic dose of this essential mineral would yield the effects they claim unless it eradicated SIBO. Recall that iodine is an effective antibacterial agent—this is why topical iodine is used on wounds and is used in the hospital to prep skin for surgery. High doses of oral iodine therefore act as an antibiotic against the pathogenic microorganisms that have ascended up the gastrointestinal tract in small intestinal bacterial overgrowth, SIBO, thereby yielding apparent health benefits. It is not the action of iodine on the human body per se, but on the pathogenic microorganisms that populate so many people today.

The key with iodine is to take a dose that is physiologic. Though it is above the RDA of 150 mcg per day, the dose required to not have a goiter (enlarged thyroid gland), the 350-500 mcg range I advocate is the range I believe that is ideal, not just adequate, and never yields toxicity or hypothyroidism. Around 20-30% of people who start out on the Wheat Belly lifestyle begin with some degree of iodine deficiency, typically manifested as fatigue, feeling cold, and inability to lose weight, reversed with iodine supplementation. (Iodine deficiency is most common in inland areas such as the American midwest and other interior regions away from the coasts, as the iodine of the earth is concentrated in the oceans.) But you can CAUSE hypothyroidism also by taking toxic doses of iodine, as this person posting her experience did.

Iodine toxicity can also be observed in coastal populations such as those in Japan who enthusiastically consume seaweed, people receiving repeated doses of iodine-containing x-ray contrast for CT scans and other tests, and people taking the toxic anti-arrhythmic drug amiodarone that contains large quantities of iodine. But you should not expose yourself to toxic doses of iodine in the hopes that, if a little bit is good, a lot more is better—not in this case.