women 14-18 years: 900 μg;
•Lactating women 19 years and older: 1100 μg.
CONCLUDING REMARKS
Proponents of Pharmacologic Iodine
Revisionist claims have been made over the last few years regarding ideal iodine intake. An argument has been put forth that since iodine has various pharmacologic effects at dose well above established levels for optimal thyroid function, then these very high doses must be physiologically essential. The proponents call on results from iodine challenge tests as proof of a deficiency existing in all or nearly all who are tested. The proposed doses are contained in a product called Lodoral®, which ranges in potency from 12500-50000 μg of iodine per tablet. These levels are 12.5-50-fold above the 1000-1100 μg. safe UL established by the WHO and the International Council on Iodine Deficiency Diseases.
Numerous problems exist with the premises of this position. Firstly, whilst it is true that nutrients may have medically useful effects when used in doses above amounts needed to fulfill their physiologic role; this does not mean that such doses are safe or appropriate for long-term use. Secondly, urinary iodine is not expected to reach a steady state for several months after iodine ingestion is raised or lowered. Therefore a 24-hour urine collection post iodine-loading dose would not reflect iodine status. Finally, the toxicology of iodine is well established. Some can manifest latent antithyroid antibodies when raising iodine intake by even a few hundred micrograms.
Whilst it is plausible that Lodoral® can help with fatigue, as many doctors have reported, this is hardly an argument to justify its use since iodine has long been known to cause stimulant like side effects early on in its toxicity. It is certainly possible to hear patients claim positive benefits from a treatment, and a clinician may not see side effects even with a high number of observations. Statistically, one could prescribe lovastatin to 6490 patients prior to seeing a single case of hepatocellular damage. Yet we take it as a given that liver damage is a risk patients face when taking statin drugs and we factor such risk into the risk/benefit assessment prior to prescribing. The risks with mega-dose iodine are quite clear. The benefits are vague and nebulous at best and there is no evidence to support putting a patient at risk for life-long thyroid disease or possibly lethal thyroid storm for the poorly substantiated possible benefits claimed by its proponents.
Relevance of Iodine to the Integrative Physician
In the context of discussions on diet and micronutrient intake, physicians should counsel patients on optimal iodine intake. Since iodine is readily absorbed, human iodine requirements are not variable and its status is predictable based on intake. Iodine assessment is not a useful part of medical screening due to its poor reliability. Since nearly all Americans consume sodium well in excess of 2500 mg daily and since processed foods are made with non-iodized salt, patients should be advised to minimize their salt intake from restaurant foods and pre-made groceries. Instead, their prime sodium intake should be from home cooked foods made with conservative use of iodized table salt or iodized sea salt. Along with iodized salt, consuming a variety of fruits, vegetables, meats, sea foods and grains can provide a basal amount of iodine. Additionally, pregnant and lactating women should be advised to consume a multivitamin containing 50-100 μg of iodine daily.
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