In reviewing the ZRT Laboratory pamphlet, “Flaws in the Urine Iodine Loading Test Can Lead to High Dose Iodine Therapy and Disrupted Thyroid Function By David T. Zava of ZRT Laboratories several points need clarification.  The iodine project, initiated by Dr. Guy Abraham, MD, goal was to investigate the role of iodine in human health and to propose a systematic approach to evaluate iodine supplementation.  The idea of whole body iodine sufficiency was a new concept that recognized that iodine is necessary for not only the thyroid gland but many other body systems.  When Dr. Zava compares the deBenoist findings of 89% iodine sufficiency in the United States with data showing iodine deficiency reported to be greater than 90% found by the Iodine Project, he is comparing two completely different measures of iodine status.  deBenoist is simply looking at minimal iodine levels that will prevent goiter.  The Iodine Project data looks at whole body iodine status.

We do not believe that this presents confusion when one understands the difference in the two protocols.  The traditional spot iodine test as well at the dry iodine spot test (ZRT Lab) are useful tools that can be used to rule out gross iodine deficiency while the 24 hour collection addresses the need to evaluate whole body iodine status.  The first concern raised by Dr Zava is iodine toxicity.  As with any supplementation there is a potential for side effects in a small fraction of the population.  According to iodine supplementation recommendation in Remington’s Pharmaceutical Sciences 15th Addition, usual adult daily dose of Lugols 5% solution is listed as between 2 drops and 6 drops daily containing between 12.5mg and 37.5mg of iodine.  There are many articles in the medical literature citing the use of gram (1000mg) quantities without adverse side effects.  The confusion about the amount of Iodine in the average Japanese diet was investigated by Dr Abraham in conversations with the authors of the Japanese paper.  The problem was found to be the amount of iodine measured on a dry or wet  basis in seaweed.  Dr. Abraham confirmed the 13.8mg calculation.  The RDA for iodine is 150mcg/day, corresponding to the amount needed to prevent goiter growth.  The detoxification of bromide and fluoride by the body can cause various side effects and should be followed by a trained medical professional.  Many physicians have found that when a patient experiences a detox reaction that decreasing the amount of iodine generally eliminates the problem.  In addition if the patient has been on a complete nutritional protocol (orthoiodosupplementation) that stresses magnesium, zinc, selenium, vitamin C as well as the B vitamins the side effects do not happen.  Laboratory technique is very important when measuring iodine, bromide or fluoride.  The laboratories now testing for these halides use ICP-MS for iodine and bromide.  Fluoride and chloride are measured by the older ISE method.  As a lab scientist Dr Zava should be aware that when high bromide levels are measured by the ISE electrode it is not iodine interference but interference from chloride (urine is very high in chloride).  This was the reason in the original work Dr Abraham’s method used a SAX column to remove chloride before a measurement was made.  It has been our experience that when comparing spot urine bromide values with a  24 hour collection (with a 50mg iodine load) that mg/L bromide levels go up after the 50mg iodine load .  Also, after several months of iodine supplementation bromide levels will go down, and the patients note improvement in general well being.

Question and Answer:


Q: How long do you need to discontinue iodine for an accurate assessment?
A: We recommend 72 hours (3 days), however, when looking at the data after 48 hours the urine iodine is close to baseline.  90% of the 50mg load is excreted in the first 24 hours so that is the reason for 90% being defined as sufficiency. A washout period of 2 days was used for the original research.
Q: Is any iodine lost in feces?
A: The 2% loss in feces is negligible.


Q: Do you use the ion electrode method or ICP-MS for testing?
A: All labs, including Hakala Research, do iodine/bromide analysis using ICP-MS (gold standard for element testing). 
Q: What is the difference between the Hakala Research load test and ZRT test?
A: The ZRT test is a variation on the spot urine test only looking for the amount of iodine required to prevent goiter growth. The Hakala Research loading test looks at whole body iodine sufficiency.

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