Iodine as a therapeutic supplement
Iodine is a vital therapeutic supplement primarily recognized for its role in thyroid health. The thyroid gland requires iodine to produce hormones that regulate metabolism in the body. While iodine is abundant in seawater, dietary sources can be scarce in inland areas, leading to deficiencies that historically resulted in conditions like goiter. The addition of iodine to table salt has significantly reduced deficiency rates in developed countries, but certain populations, such as those following a vegan diet, may still be at risk and could benefit from supplementation.
Supplemental iodine has also been suggested for conditions like cyclic mastalgia, characterized by breast pain related to the menstrual cycle. Although some clinical studies indicate potential benefits, the evidence is considered weak. Recommended dosages typically range from 150 to 200 micrograms daily, depending on age and life stage, with higher amounts advised for pregnant and nursing women. While iodine is generally safe at recommended levels, excessive intake can lead to thyroid dysfunction and other health issues. Therefore, it's recommended that individuals consult with healthcare professionals before starting iodine supplementation, especially to avoid interactions with certain medications.
Iodine as a therapeutic supplement
DEFINITION: Natural substance of the human body used as a supplement to treat specific health conditions.
PRINCIPAL PROPOSED USE: Nutritional deficiency
OTHER PROPOSED USE: Cyclic mastalgia
Overview
The thyroid gland, located just above the middle of the collarbone, needs iodine to make thyroid hormone, which maintains normal metabolism in all cells of the body. Principally found in seawater, dietary iodine can be scarce in many inland areas, and deficiencies were common before iodine was added to table salt. Iodine deficiency causes enlargement of the thyroid, a condition known as goiter.
However, if a person is not deficient in iodine, taking extra iodine will not help the thyroid work better, and it might even cause problems. For reasons that are not clear, supplementary iodine might also be helpful for cyclic mastalgia.
Requirements and Sources
The official U.S. recommendations (in micrograms) for daily intake of iodine are as follows:
Infants to six months of age (110) and seven to twelve months (130); children one to eight years (90); children nine to thirteen years (120); children fourteen to eighteen (150); individuals over nineteen (150); pregnant women (220); and nursing women (290).
Individuals who eat a vegan diet are at a greater risk of iodine deficiency and may need to supplement their diet with a vegan-friendly supplement like NOW Kelp.
Iodine deficiency is rare in developed nations because of the use of iodized salt. Seafood and kelp contain very high levels of iodine, as do salty processed foods that use iodized salt. Greek yogurt and other dairy products, eggs, and prunes are also good sources of iodine. Supplements of kelp, a natural source of iodine, are also available. Most iodine is in the form of iodide, but a few studies suggest that a special form of iodine called molecular iodine may be better than iodide.
Therapeutic Dosages
A typical therapeutic dosage of iodide or iodine is sold as potassium iodide or sodium iodide at 200 micrograms daily. Most multivitamins contain around 150 micrograms of iodine.
Therapeutic Uses
Iodine supplements have been proposed as a treatment for cyclic mastalgia. Cyclic mastalgia is characterized by breast pain and lumpiness that usually cycles in relation to the menstrual period.
Other uses for iodine supplements include treating thyroid disorders, protecting the thyroid from radiation exposure, ulcers of the feet, mouth irritation associated with certain cancer treatments, and fibrotic breast disease.
Scientific Evidence
Three clinical studies provide weak evidence that supplements providing iodine may be helpful in treating cyclic mastalgia. These studies suggest that either iodide or iodine (the pure molecular form) might be useful. In one double-blind, placebo-controlled trial among this group, a study that enrolled fifty-six individuals, molecular iodine was found superior to placebo in relieving pain and reducing the number of cysts.
Another of these studies compared molecular iodine to iodide. Molecular iodine was no more effective than iodide but was deemed superior because it induced fewer side effects and did not affect the thyroid.
Iodine supplementation for pregnant women has long been believed to be critical in supporting fetal development. A meta-analysis in the mid-2020s found that this assertion calls for more examination that considers the degree of iodine deficiency and other independent factors that may impact fetal development.
Safety Issues
When taken at the recommended dosage, iodine and iodide are safe nutritional supplements. However, excessive doses of iodide can actually cause thyroid problems, including both hypothyroidism and hyperthyroidism. There is also a speculative link between excessive iodide intake and thyroid cancer. For these reasons, iodide intake above nutritional recommendations is not advised except under physician supervision.
Iodine can interact with several medications, including amiodarone (Cordarone), lithium, and antithyroid drugs like methimazole (Tapazole). Taking iodine with spironolactone (Aldactone) and amiloride (Midamor) or similar medications can cause a spike in potassium levels in the blood.
Bibliography
Croce, Laura, et al. “Iodine Status and Supplementation in Pregnancy: An Overview of the Evidence Provided by Meta-analyses.” Reviews in Endocrine and Metabolic Disorders, vol. 24, no. 2, 2023, pp. 241-250. doi:10.1007/s11154-022-09760-7.
Ghent, W. R., et al. “Iodine Replacement in Fibrocystic Disease of the Breast.” Canadian Journal of Surgery vol. 36, 1993, 453-60.
Hatch-McChesney, Adrienne and Harris R. Lieberman. "Iodine and Iodine Deficiency: A Comprehensive Review of a Re-Emerging Issue." Nutrients, vol. 14, no. 17, 24 Aug. 2022, p. 3474, doi.org/10.3390/nu14173474.
"Iodine - Uses, Side Effects, and More." WebMD, www.webmd.com/vitamins/ai/ingredientmono-35/iodine. Accessed 20 Sept. 2024.
"Iondine." National Institutes of Health (NIH), 1 May 2024, ods.od.nih.gov/factsheets/Iodine-HealthProfessional. Accessed 20 Sept. 2024.