4
4.44
6
Consuming too much iodine is unlikely from dietary sources alone; most cases of iodine toxicity are linked to excessive intake of certain drugs, nutritional supplements or environmental exposure .
In the US, the RDA (Recommended Dietary Allowance) for iodine is 150 micrograms daily for individuals who are not pregnant or lactating. Acute iodine toxicity is rare and only occurs when taking doses hundreds of times greater than the RDA.
According to 2014 research, “excess iodine exposure generally does not result in any apparent clinical consequences”. [1] In cases of iodine poisoning, mild symptoms can develop including a burning sensation in the throat and stomach, fever, nausea, vomiting or diarrhea.
In sensitive people with specific risk factors, excessive iodine intake or exposure can cause thyroid dysfunction, a weak pulse, cyanosis or coma. Groups at highest risk for iodine toxicity include those with thyroid disease, the elderly, newborns and developing babies.
Brain Power
Thyroid Function
Weight Loss- Important for thyroid hormones & metabolism
- Supports mental function & immunity
- Essential nutrient with multiple roles in the body
Top Iodine Products* ❯How Much is Too Much Iodine?
The human body requires iodine for thyroid function, supporting development and for metabolic function.
However, getting too much of this element is possible and can cause serious side effects.
Most people will not get too much iodine in their diets if relying exclusively on food sources for this mineral.
Sea vegetables like kelp contain the highest known concentrations of iodine
Some other good sources of iodine include unrefined sea salt, green leafy vegetables, potatoes, raw cheese, yogurt, strawberries, cranberries and navy beans.
While the RDA established by the Food and Drug Administration is 150 micrograms per day, people consume many times more than this amount without experiencing adverse effects.
The average woman in Japan is said to consume between 5280 mcg to 13,800 mcg of iodine daily; an intake amount which is not associated with negative effects.
According to the Natural Medicines Comprehensive Database (NMCD), iodine is Likely Safe in amounts that do not exceed 1100 mcg per day. This is considered to be the Upper Tolerable Intake level.
More than one study shows that iodine is also likely safe if administered at higher doses in patients monitored by medical professionals.
However, consuming more than this amount is not associated with any medicinal benefits for the typical person and should be avoided.
NMCD states that iodine is Possibly Unsafe in high doses over long periods of time. Chronic doses over 1100 mcg daily may increase the risk of thyroid dysfunction, thyroid papillary cancer, thyroiditis, thyrotoxicosis and/or atrial fibrillation.
Acute iodine overdoses typically involve ingestion of significantly larger dosages.
Iodine poisoning could be caused by use of Lugol’s solution, Pima syrup, Cordarone (amiodarone HCl), potassium iodide supplements or radioactive iodine.
Too Much Iodine Side Effects
The primary negative effect of consuming too much supplemental iodine is thyroid dysfunction.
Excessive intake of this mineral in the form of a dietary supplement can lead to iodine-induced hyperthyroidism (IIH). This has been observed in patients with a deficiency who were given supplements to improve their iodine-status.
IIH can lead to symptoms including excess weight loss, muscle weakness, increased body temperature, tachycardia or fast heart beat.
Other possible side effects of iodine toxicity include nausea, abdominal pain, rhinorrhea (excessive mucus in nasal cavity), headache and diarrhea.
Chronic or excessive topical application of iodine solutions may cause mouth burns, soreness in teeth and gums, sneezing, eyelid swelling and fever.
Iodine may also interact with certain medications and herbal supplements, especially those with anti-thyroid properties. Some of these include warfarin, aspirin and lithium.
Severe cases of iodine poisoning linked to an acute overdose can also result in seizures, shock, stupor, delirium, coma, no urinary output, vomiting and bloody diarrhea.
If Iodine toxicity is suspected, the Milton S. Hershey Medical Center at Penn State says to immediately seek medical help by calling the national Poison Help hotline in the United States 1-800-222-1222
Other side effects and interactions are possible if taking too much iodine. It is best to seek medical advice before beginning to increase your iodine intake, either by diet or supplementation.
Iodine Toxicity in Children
In children, iodine is rated as Likely Safe in the following amounts per age group:
- 200 mcg daily for ages 1 to 3 years;
- 300 mcg daily for ages 4 to 8 years;
- 600 mcg daily for ages 9 to 13 years;
- 900 mcg daily for adolescents;
Higher doses than those above may cause thyroid dysfunction.
Too Much Iodine in Pregnancy
The US RDA for pregnant women is 220 mcg per day. For those women who are breastfeeding, the RDA is 290 mcg daily.
However, some doctors believe that pregnant and nursing women should increase their intake between two to three times more than the dosage recommended to women who are not pregnant or lactating.
Iodine deficiency is the leading cause of mental retardation in babies and it is important to get enough of this mineral to support normal development.
If you are pregnant or nursing, then ask your doctor about the best iodine dosage level for you and your baby.
Lab Testing for Iodine Levels
According to the World Health Organization (WHO), about 40% of the world’s population is likely deficient in iodine.
Some medical doctors believe that iodine deficiencies are very common and tend to go underdiagnosed.
According to Dr. David Brownstein, 19 out of 20 patients he treats are iodine deficient. He bases this on more than 6000 patients he and his colleagues have tested over the years.
If you think you may have signs of low iodine levels, there is a simple to perform at-home test to determine if a supplement might be helpful.
Purchase a USP iodine tincture from a local drug store. Using a cotton ball, apply some of the tincture to your inner upper arm between the tricep and bicep. Rub on a spot about the size of a silver dollar.
If the brown/orange stain of the iodine tincture disappears within 2 to 4 hours, then you may be deficient and should consider further testing with your doctor.
Note that USP iodine tinctures are not intended to be ingested and should only be applied topically. Do not use this product as a dietary supplement.
Elemental iodine is toxic to human tissues and damages them on contact. However, you will probably never be exposed to elemental iodine.
The most popular form of iodine used as a supplement is sodium iodide.
Nascent iodine is believed to be safer and significantly more bioavailable, which means it is better absorbed and utilized by the body’s cells.
Consult with a doctor or qualified health care provider to determine which form of this supplement is best for you and which dosage to take so you can avoid iodine toxicity symptoms.
- Leung, Angela M., and Lewis E. Braverman. “Consequences of Excess Iodine.” Nature reviews. Endocrinology 10.3 (2014): 136–142. PMC. Web. 11 July 2016.
- Fabian Rohner,5,6,15 Michael Zimmermann,7,8,15 Pieter Jooste,9,10,15 Chandrakant Pandav,11,12,15 Kathleen Caldwell,13,15 Ramkripa Raghavan,14 and Daniel J. Raiten14,* Biomarkers of Nutrition for Development—Iodine Review1,2,3,4 J Nutr. 2014 Aug; 144(8): 1322S–1342S.
- Vermeulen H1, Westerbos SJ, Ubbink DT. Benefit and harm of iodine in wound care: a systematic review. J Hosp Infect. 2010 Nov;76(3):191-9. doi: 10.1016/j.jhin.2010.04.026. Epub 2010 Aug 12.
- RS1, Witt KL, Alden CJ, Cockerham LG. Toxicology of methyl bromide. Rev Environ Contam Toxicol. 1995;142:65-85.
- Kapil U1. Health consequences of iodine deficiency. Sultan Qaboos Univ Med J. 2007 Dec;7(3):267-72.
- Ahad, Farhana, and Shaiq A. Ganie. “Iodine, Iodine Metabolism and Iodine Deficiency Disorders Revisited.” Indian Journal of Endocrinology and Metabolism 14.1 (2010): 13–17. Print.
- Sterling JB1, Heymann WR. Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications. J Am Acad Dermatol. 2000 Oct;43(4):691-7.
Article last updated on: July 22nd, 2018 by Nootriment
4 Comments
Bonjour je suis en hyperhyroïdie Hashimoto mon médecin me donne de l’iode, depuis quelques jours j’avais les yeux gonflés, des palpitations et des vertiges
C’est du fucus, pensez vous que c’est à cause de ça ?? Merci
Hypothyroïdie pardon
In East Asia they eat certain foods to prevent excessive iodine absorption. So they can eat more than a small amount of seaweed usually without any problem.
Such as cabbage, spinach, broccoli, cauliflower and brussels sprouts which all contain a lot of goitrogens that help to inhibit iodine absorption. Many other foods can do it as well.
No, it’s not wise to eat a seaweed salad by itself every day. Pair it with a side dish of something to help prevent excessive iodine absorption if you eat seaweed a lot.
I think green tea may also have goitrogens… so it may actually cause thyroid problems if you don’t ever eat seaweed. Green tea perhaps needs some iodine containing food so there is a balance? I’m not sure.