Iodine is a chemical element. The body needs iodine but cannot make it. The needed iodine must come from the diet. As a rule, there is very little iodine in food, unless it has been added during processing, which is now the case with salt. Most of the world’s iodine is found in the ocean, where it is concentrated by sea life, especially seaweed.
- The thyroid gland needs iodine to make hormones. If the thyroid doesn’t have enough iodine to do its job, feedback systems in the body cause the thyroid to work harder. This can cause an enlarged thyroid gland (goiter), which becomes evident as a swollen neck.
- Other consequences of not having enough iodine (iodine deficiency) are also serious. Iodine deficiency and the resulting low levels of thyroid hormone can cause women to stop ovulating, leading to infertility. Iodine deficiency can also lead to an autoimmune disease of the thyroid and may increase the risk of getting thyroid cancer. Some researchers think that iodine deficiency might also increase the risk of other cancers such as prostate, breast, endometrial, and ovarian cancer.
- Iodine deficiency during pregnancy is serious for both the mother and the baby. It can lead to high blood pressure during pregnancy for the mother, and mental retardation for the baby. Iodine plays an important role in development of the central nervous system. In extreme cases, iodine deficiency can lead to cretinism, a disorder that involves severely stunted physical and mental growth.
- Iodine deficiency and its consequences, including goiter
- Skin disease caused by a fungus (cutaneous sporotrichosis)
- Fibrocystic breast disease
- Preventing breast cancer
- Eye disease
- Heart disease and stroke
- As an expectorant.
- Radiation emergencies, to protect the thyroid gland against radioactive iodides. Potassium iodide tablets for use in a radiation emergency are available as FDA-approved products (ThyroShield, Iosat) and on the Internet as food supplements. Potassium iodide should only be used in a radiation emergency, not in advance of an emergency to prevent sickness.
- Iodine is applied to the skin to kill germs, prevent soreness inside the mouth (mucositis) caused by chemotherapy, and treat diabetic ulcers.
- Also used for water purification.
- Iodine reduces thyroid hormone and can kill fungus, bacteria, and other microorganisms such as amoebas. A specific kind of iodine called potassium iodide is also used to treat (but not prevent) the effects of a radioactive accident.
- Conditions related to too much thyroid gland activity (hyperthyroidism).
- Radiation emergency associated with the use of radioactive iodides.
- Skin infection caused by the fungus Sporothrix (cutaneous sporotrichosis).
- Iodine deficiency: Taking iodine supplements, including iodized salt, is effective for preventing and treating iodine deficiencies.
- Radiation exposure: Taking iodine by mouth is effective for protecting against exposure to radioactive iodides in a radiation emergency.
- Thyroid conditions: Taking iodine by mouth can improve thyroid storm and hyperthyroidism. Also, taking iodized salt in addition to thyroxine after surgery for thyroid disease appears to reduce the size of the thyroid.
- Iodine is LIKELY SAFE for most people when taken by mouth at recommended amounts or when applied to the skin appropriately using approved products.
- Iodine can cause significant side effects in some people. Common side effects include nausea and stomach pain, runny nose, headache, metallic taste, and diarrhea.
- In sensitive people, iodine can cause side effects including swelling of the lips and face (angioedema), severe bleeding and bruising, fever, joint pain, lymph node enlargement, allergic reactions including hives, and death.
- Large amounts or long-term use of iodine are POSSIBLY UNSAFE. Adults should avoid prolonged use of doses higher than 1100 mcg per day (the upper tolerable limit, UL) without proper medical supervision. In children, doses should not exceed 200 mcg per day for children 1 to 3 years old, 300 mcg per day for children 4 to 8 years old, 600 mcg per day for children 9 to 13 years old, and 900 mcg per day for adolescents. These are the upper tolerable limits (UL).
- In both children and adults, there is concern that higher intake can increase the risk of side effects such as thyroid problems. Iodine in larger amounts can cause metallic taste, soreness of teeth and gums, burning in mouth and throat, increased saliva, throat inflammation, stomach upset, diarrhea, wasting, depression, skin problems, and many other side effects.
- When iodine is used directly on the skin, it can cause skin irritation, stains, allergic reactions, and other side effects. Be careful not to bandage or tightly cover areas that have been treated with iodine to avoid iodine burn.
- Pregnancy and breast-feeding: Iodine is LIKELY SAFE when taken by mouth in recommended amounts or when applied to the skin appropriately using an approved product (2% solution). Iodine is POSSIBLY UNSAFE when taken by mouth in high doses. Do not take more than 1100 mcg of iodine per day if you are over 18 years old; do not take more than 900 mcg of iodine per day if you are 14 to 18 years old. Higher intake might cause thyroid problems.
- Autoimmune thyroid disease: People with autoimmune thyroid disease may be especially sensitive to the harmful side effects of iodine.
- A type of rash called dermatitis herpetiformis: Taking iodine can cause worsening of this rash.
- Thyroid disorders, such as too little thyroid function (hypothyroidism), an enlarged thyroid gland (goiter), or a thyroid tumor: Prolonged use or high doses of iodine might make these conditions worse.
Major Interaction – Do not take this combination
- Medications for an overactive thyroid (Antithyroid drugs) interacts with Iodine. Iodine can affect the thyroid. Taking iodine along with medications for an overactive thyroid might decrease the thyroid too much. Do not take iodine supplements if you are taking medications for an overactive thyroid. Some of these medications include methenamine mandelate (Methimazole), methimazole (Tapazole), potassium iodide (Thyro-Block), and others.
Moderate Interaction – Be cautious with this combination
- Amiodarone (Cordarone) interacts with Iodine. Taking iodine supplements along with amiodarone (Cordarone) might cause too much iodine in the blood. Too much iodine in the blood can cause side effects that affect the thyroid.
- Lithium interacts with Iodine. Lithium can inhibit thyroid function. Concomitant use with iodine may have additive or synergistic hypothyroid effects. Monitor thyroid function.
- Medications for high blood pressure (ACE inhibitors) interacts with Iodine. Some medications for high blood pressure might decrease how quickly the body gets rid of potassium. Most iodide supplements contain potassium. Taking potassium iodide along with some medications for high blood pressure might cause too much potassium in the body. Do not take potassium iodide if you are taking medications for high blood pressure. Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), lisinopril (Prinivil, Zestril), ramipril (Altace), and others.
- Medications for high blood pressure (Angiotensin receptor blockers (ARBs)) interacts with Iodine. Some medications for high blood pressure might decrease how quickly the body gets rid of potassium. Most iodine supplements contain potassium. Taking potassium iodide along with some medications for high blood pressure might cause too much potassium in the body. Do not take potassium iodide if you are taking medications for high blood pressure. The ARBs include losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro), candesartan (Atacand), telmisartan (Micardis), and eprosartan (Teveten).
- Water pills (Potassium-sparing diuretics) interacts with Iodine. Most iodine supplements contain potassium. Some “water pills” might also increase potassium in the body. Taking potassium iodide along with some “water pills” might cause too much potassium to be in the body. Do not take potassium iodide if you are taking “water pills” that increase potassium in the body. Some “water-pills” that increase potassium in the body include spironolactone (Aldactone), triamterene (Dyrenium), and amiloride (Midamor).
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Source: WebMD, “Iodine”, www.webmd.com/vitamins-supplements/