Iodine
Uses
Iodine is a trace mineral needed to make thyroid hormones, which are necessary for maintaining normal metabolism in all cells of the body.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
| Used for | Why |
|---|---|
3 Stars Goiter Use a mouthrinse or toothpaste containing zinc regularly | Iodine supplementation can be an effective treatment of iodine deficiency hypothyroidism and may halt goiter growth and, in early stages, shrink goiters. supplementation can be an effective treatment of iodine deficiency hypothyroidism and can halt the growth of goiter if the cause is not complicated by malnutrition or environmental and dietary goitrogens. Iodine supplements will help to shrink goiters during early stages, but they have no effect in later stages. Ingestion of 2,000 to 6,000 mcg of iodine daily over long periods of time can be toxic to the thyroid and can be a cause of goiter. |
3 Stars Pregnancy and Postpartum Support Refer to label instructions | Iodine is an essential nutrient for the development of the fetal thyroid gland which, in turn, is important for brain development. Iodine is an essential nutrient for the development of the fetal thyroid gland which, in turn, is important for brain development. Even mild iodine deficiency during pregnancy may have an adverse effect on cognitive function of the child. In a preliminary study of women in Italy, iodine deficiency severe enough to cause hypothyroidism during pregnancy was associated with an increased risk of attention deficit-hyperactivity disorder in their children. However, excessive iodine intake can also adversely affect the thyroid gland. Women who are pregnant or planning to become pregnant should ask their healthcare professional whether they should take a prenatal supplement that contains iodine. |
2 Stars Attention Deficit–Hyperactivity Disorder Consult a qualified healthcare practitioner | In one study, iodine deficiency during pregnancy was associated with the babies being born with increased ADHD risk. If you are pregnant or trying to get pregnant, discuss whether you might need iodine supplements with your doctor. In a preliminary study of women in Italy, deficiency severe enough to cause hypothyroidism during pregnancy was associated with an increased risk of ADHD in their children. Women who are contemplating pregnancy or who are pregnant should get adequate amounts of iodine in their diet and should discuss with their healthcare provider whether iodine supplementation is appropriate. |
2 Stars Hypothyroidism Consult a qualified healthcare practitioner | Iodine deficiency and excessive iodine intake can both lead to hypothyroidism, so ask your doctor if supplementing with iodine is right for you. The relationship between and thyroid function is complex. Iodine is required by the body to form thyroid hormone, and iodine deficiency can lead to goiter and hypothyroidism. Severe and prolonged iodine deficiency can potentially lead to serious types of hypothyroidism, such as myxedema or cretinism. It is estimated that one and a half billion people living in 118 countries around the world are at risk for developing iodine deficiency. Today, most cases of iodine deficiency occur in developing nations. In industrialized countries where iodized salt is used, iodine deficiency has become extremely rare. On the other hand, iodine toxicity has become a concern in some of these countries. Excessive iodine intake can result in either hypothyroidism or hyperthyroidism (overactive thyroid). Sources of iodine include foods (iodized salt, milk, water, seaweed, ground beef), dietary supplements (multiple vitamin-mineral formulas, seaweed extracts), drugs (potassium iodide, amiodarone, topical antiseptics), and iodine-containing solutions used in certain laboratory tests. Many nutritional supplements contain 150 mcg of iodine. While that amount of iodine should prevent a deficiency, it is not clear whether supplementing with iodine is necessary or desirable for most people. Those wishing to take a nutritional supplement containing iodine should consult a doctor. |
2 Stars Pregnancy Consult a qualified healthcare practitioner | In one study, iodine deficiency during pregnancy was associated with the babies being born with increased ADHD risk. If you are pregnant or trying to get pregnant, discuss whether you might need iodine supplements with your doctor. In a preliminary study of women in Italy, deficiency severe enough to cause hypothyroidism during pregnancy was associated with an increased risk of ADHD in their children. Women who are contemplating pregnancy or who are pregnant should get adequate amounts of iodine in their diet and should discuss with their healthcare provider whether iodine supplementation is appropriate. |
1 Star Fibrocystic Breast Disease Refer to label instructions | Iodine appears to be helpful in treating FBD, it should be taken only under the guidance of a healthcare practitioner. Some doctors use to treat FBD symptoms. In animals, iodine deficiency can cause the equivalent of FBD. What appears to be the most effective form—diatomic iodine—is not readily available, however. Some people are sensitive to iodine and high amounts can interfere with thyroid function. Therefore, supplemental iodine should only be taken with the guidance of a healthcare practitioner. |
How to Use It
Since the introduction of iodized salt, iodine supplements are unnecessary and not recommended for most people. For strict vegetarians who avoid salt and sea vegetables, 150 mcg per day is commonly supplemented. This amount is adequate to prevent a deficiency and higher amounts are not necessary.
Where to Find It
Seafood, iodized salt, and sea vegetables—for example, kelp—are high in iodine. Processed food may contain added iodized salt. Iodine is frequently found in dairy products. Vegetables grown in iodine-rich soil also contain this mineral.
Possible Deficiencies
People who avoid dairy, seafood, processed food, and iodized salt can become deficient. Iodine deficiency can cause low thyroid function, goiter, and cretinism. Although iodine deficiencies are now uncommon in Western societies, the U.S. population has shown a trend of significantly decreasing iodine intake from 1988–1994.1 If this trend continues, iodine deficiency diseases may become more common.
Severe iodine deficiency during critical periods of brain development can lead to physical abnormalities and profound mental impairment. Little is known about the effects of mild iodine deficiency on neurological development and cognitive function. Iodine deficiency has become more common in New Zealand because if the lower concentration of iodine in milk resulting from the discontinuation of the use of iodine-containing sanitizers in the dairy industry and because of the declining use of iodized salt along with increasing consumption of processed foods made with non-iodized salt. 184 children (aged 10 to 13 years) in Dunedin, New Zealand, were randomly assigned to receive, in double-blind fashion, 150 mcg/day of iodine or placebo for 28 weeks. At baseline, children were mildly iodine-deficient (median urinary iodine concentration, 63 mcg/L; thyroglobulin concentration, 16.4 mcg/L). After 28 weeks, iodine status improved in the supplemented group (urinary iodine concentration, 145 mcg/L; thyroglobulin, 8.5 mcg/L), whereas the placebo group remained iodine-deficient. Iodine supplementation significantly improved scores on 2 of 4 tests of cognitive function assessed. The overall cognitive score was significantly greater in the iodine group than in the placebo group (p = 0.011). Iodine supplementation had no significant effect on the serum total T4 level. It is concluded that iodine supplementation improved cognitive function in mildly iodine-deficient children, and that mild iodine deficiency could prevent children from attaining their full intellectual potential.
Best Form to Take
Common iodine supplement preparations include potassium iodide, potassium iodate, and a combination of iodine and potassium iodide, otherwise known as Lugol’s solution.2
Interactions with Supplements, Foods, & Other Compounds
Children with iodine deficiency may also have iron-deficiency anaemia, and this anaemia may interfere with the therapeutic action of iodine supplementation.3 Correcting iron deficiency in such children with iron supplements has been shown to improve the efficacy of oral iodine in treating goitre.4
Interactions with Medicines
Side Effects
High amounts (several milligrams per day) of iodine can interfere with normal thyroid function and should not be taken without consulting a doctor.5 Although potassium iodide supplementation (prescribed for some skin disorders) is usually well-tolerated, it has been known to produce adverse reactions such as rashes, itching or lesions on the skin, gastro-intestinal symptoms, or hypothyroidism, especially in people with a prior history of thyroid problems.6 Because of such potential problems, the use of potassium iodide therapy should be supervised by a doctor. The average diet provides about four times the recommended amount of iodine. For susceptible people, that amount of iodine may be enough to cause health problems.7 A possible link to thyroid cancer has been observed in areas where an iodine-rich diet is consumed,8, 9 and among populations that supplement with iodine.10, 11 However, there is insufficient evidence to conclude that iodine supplementation is responsible for the increased incidence of thyroid cancer. Some people react to supplemental iodine, the first symptom of which is usually an acne-like rash.
When people with small, nontoxic goitre (living in areas not deficient in iodine) received iodine injections, they had a higher incidence of abnormal antibodies suggestive of the early stages of autoimmune thyroid disease.12
1. Hollowell JG, Staehling NW, Hannon WH, et al. Iodine nutrition in the United States. Trends and public health implications: iodine excretion data from National Health and Nutrition Examination Surveys I and III (1971-1974 and 1988-1994). J Clin Endocrinol Metab 1998;83:3401-8.
2. Gaby, AR. Nutritional Medicine. Concord, NH: Fritz Perlberg Publishing, 2011.
3. Zimmermann M, Adou P, Torresani T, et al. Persistence of goiter despite oral iodine supplementation in goitrous children with iron deficiency anemia in Cote d'Ivoire. Am J Clin Nutr 2000;71:88-93.
4. Zimmermann M, Adou P, Torresani T, et al. Iron supplementation in goitrous, iron-deficient children improves their response to oral iodized oil. Eur J Endocrinol 2000;142:217-23.
5. Mu L, Derun L, Chengyi Q, et al. Endemic goiter in central China caused by excessive iodine intake. Lancet 1987;2:257-9.
6. Heymann WR. Potassium iodide and the Wolff-Chaikoff effect: Relevance for the dermatologist. J Am Acad Dermatol. 2000 Mar;42:490-2.
7. Pennington JA. A review of iodine toxicity reports. J Am Diet Assoc 1990;90:1571-81.
8. Williams ED, Doniach I, Bjarnason O, et al. Thyroid cancer in an iodide rich area. Cancer 1977;39:215-22.
9. Kim JY, Kim KR. Dietary iodine intake and urinary iodine excretion in patients with thyroid diseases. Yonsei Med J. 2000;41:22-8.
10. Harach HR, Williams ED. Thyroid cancer and thyroiditis in the goitrous region of Salta, Argentina, before and after iodine prophylaxis. Clin Endocrinol (Oxf) 1995;43:701-6.
11. Harach HR, Escalante DA, Onativia A, et al. Thyroid carcinoma and thyroiditis in an endemic goitre region before and after iodine prophylaxis. Acta Endocrinol (Copenh) 1985;108:55-60.
12. Papanastasiou L, Alevizaki M, Piperingos G, et al. The effect of iodine administration on the development of thyroid autoimmunity in patients with nontoxic goiter. Thyroid 2000;10:493-7.
Last Review: 06-01-2015
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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2024.
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