Why Is Iodine Important and How Should I Test It?
Iodine is a main mineral that supports the body’s metabolism. From estrogen regulation, cell division, body temperature regulation, energy levels, and thyroid health, iodine is involved. Even though a blood (serum) test for iodine exists, this value is not the most efficient at measuring elevations or depletions. Serum is not where the steady-state biochemistry for iodine takes place. Iodine is concentrated in various tissues in the body, therefore these tissues can be depleted while the serum may show a normal range. The thyroid concentrates about 75% of the body’s iodine. Other tissues that sequester iodine to a lesser extent are gastric mucosa, salivary glands, the choroid plexus, and breast tissue.
The 24-hour urinary iodine test is also available. A measurable amount of iodine is excreted in urine, however, the problem with this test has always been the procedure for collection, which is logistically difficult for most people. Upwards of 40% of people who collect urine over 24 hours miss collections or do not store the urine appropriately. In addition, iodine levels in both the serum and urine are both heavily individualized based upon specific thyroid metabolism. Testing levels for comparison have not been established with reliability.
Easily absorbed from the intestines, iodine is stored in the thyroid and is used mainly to manufacture the thyroid hormones T3 and T4. The number represents the amount of iodine molecules attached on the thyroglobulin backbone. The enzyme Thyroid Peroxidase requires selenium to cleave (remove) one iodine from T4 to create the final T3, a bioavailable, readily absorbed thyroid hormone that regulates cellular metabolism.
The relationship between iodine deficiency and thyroid disease have been established since the early 20th century. Iodine is actually the rate-limiting element for the synthesis of thyroid hormones, so its supplementation with low-functioning thyroid is important.
Iodine is involved with estrogen regulation in breast tissue, especially during breastfeeding. Numerous studies show molecular iodine inhibits cell growth in both breast tumor and fibrocystic breast tissue. Fibroids in uterine, breast, and thyroid tissue strongly indicate tissue-level iodine depletion.
The Iodine Patch Test
The iodine patch test proves itself to be the most useful ballpark measurement for iodine status. The method involves painting a 2 inch x 2 inch square of 5% Strong Lugol's Iodine solution on the skin. Lugols does not denote a brand name, but rather the ratio of iodine/iodide in the formula. Not just any topical iodine can be used; both the concentration and form of iodine solution are important. If the 5% Lugols iodine patch quickly fades within 12 hours, the individual is deficient. If the patch remains after 12 hours, iodine is sufficient.
Often people observe the patch every 2-3 hours. Supplementation of iodine will depend upon how fast the patch disappears. Most people do fine with iodine supplementation, but certain individuals will need to be guided by a healthcare professional who is educated in iodine supplementation methods.
Iodine Patch Testing Procedure:
Observe your patch every 2-3 hours to notice how quickly it fades. Often, people take a picture on their phone of the initial patch for comparison. Try to avoid showering, bathing, swimming, or heavily sweating while wearing the patch. Do not wash the patch off. You may want to set an alarm on your phone to be reminded to observe the patch.
Degree of fading:
0 = no fading (red-orange)
1= slightly faded (dark orange)
2 = half-faded (lighter orange)
3 = significantly faded (dark yellow)
4 = almost or completely gone (yellow to flesh colored)
Make the following observations:
2-3 Hours Later - Degree of Fading:
4-5 Hours Later - Degree of Fading:
6-7 Hours Later - Degree of Fading:
8-9 Hours Later - Degree of Fading:
10-11 Hours Later - Degree of Fading:
*12 Hours Later - Degree of Fading: This final reading is the main determinant for iodine dosing.