How to counteract too much iodine?

In this brief article, we will answer the question, “How to counteract too much iodine?”. We will further elaborate on the symptoms and causes of too much iodine in the body as well as the risk factors for iodine poisoning. 

How to counteract too much iodine? 

The thyroid gland of human adults secretes about 80 mg thyroxine per day, corresponding to 52 mg iodine, an amount of iodine the gland must take up daily in order to remain in balance. It is generally assumed that in adults this is the case at a dietary iodine intake between 100 and 150 mg per day. Excessive iodine can lead either to hyperthyroidism or hypothyroidism, depending on the patient (1).

If your blood tests report high levels of iodine in your body, and you are searching for ways to counteract it, do not worry, here in this article we have prepared a list of ways that can help you counteract too much iodine. Try the approaches below:

  • Avoid iodine-rich foods
  • Stop taking multivitamins 
  • Stop taking thyroid hormones

Avoid iodine-rich foods 

People with too much iodine are recommended to avoid using salt fortified with iodine and to limit their consumption of foods containing iodine, for instance, cheddar cheese, seafood, baked cod, seaweed, yogurt, milk, egg, and white-enriched bread. Seaweed preparations containing up to 2 mg iodine per gram in protein-bound form available in dried form in health-food shops and popular parts of the diet in coastal regions of Japan. Erythrosine (food additive E127) contains 57% iodine and is used, for example, to improve the color of canned cherries or of candies. These should be avoided (1).

Stop taking supplements 

Supplements often consist of iodine in the form of KI or NaI. Supplements that contain kelp are rich in iodine. If you are taking any such supplements quit taking them right away and only proceed with your doctor’s advice.  

Stop taking thyroid hormones

If an individual has hypothyroidism because of the consumption of too much iodine, taking less iodine often counteracts the problem, however, some people have to take thyroid hormones throughout their entire life.

Role of iodine in the human body 

Iodine is a nutrient that is required by the body to help the thyroid work effectively.

Thyroid hormones play a crucial part in a variety of body processes, such as metabolic reactions, bone strength, immunity, and the growth of the central nervous system.

Iodine aids to transform thyroid-stimulating hormone (TSH) into triiodothyronine (T-3) and thyroxine (T-4). This reaction is important for the thyroid to work effectively.

The imbalance of iodine can result in hyperthyroidism and hypothyroidism. Around 70-80 percent of iodine is present in the thyroid gland located in the neck. While the remainder is present in the blood, muscles, ovaries, and other regions of the body.

Extrathyroidal iodine also has other functions. It removes toxic chemicals and biological toxins; suppresses autoimmunity; strengthens the T-cell adaptive immune system; and protects against abnormal growth of bacteria in the stomach, Helicobacter pylori in particular. It is also claimed to prevent breast cancer. Epidemiological studies show that a high intake of iodine is associated with a low incidence of breast cancer, and a low intake with a high incidence of breast cancer (4).

Other investigators have shown that iodide is a specific scavenger of hydroxyl radicals, and that it, like vitamin C, increases the antioxidant status of human serum. Iodine defends brain cells in rats from lipid peroxidation, attaching to the double bonds of polyunsaturated fatty acids in cellular membranes, rendering them less susceptible to free radicals (4).

Too much intake of iodine is rare. It typically occurs from taking iodine supplements to treat a long-term iodine insufficiency. 

Occasionally people who reside close to the sea ingest too much iodine as they eat more amounts of seafood and seaweed and drink water that has increased iodine levels.

The recommended dose of iodine 

The recommended dose of iodine, when a person turns 14, is 150 µg for both males and females.

Symptoms of too much iodine 

Iodine in excess can cause hypothyroidism or hyperthyroidism with or without goiter, euthyroid goiter and silent or manifest autoimmune thyroid disease (1).

The symptoms of iodine toxicity range from relatively benign to extreme, based upon the amount of iodine that is in the body. Most persons tolerate a chronic excess of 30 mg up to 2 g iodide per day, without clinical symptoms, but a detailed analysis reveals a persistent drop of serum T4 and T3 of 25% and 15%, respectively, and a rise of TSH of 2 mUl1; all values, though, remain well within the normal range, and  there are no clinical signs of thyroid dysfunction or goiter, even though sonographic thyroid volume is slightly increased (1).

The lethal dose varies from 200 mg to > 20 g. Mild symptoms of iodine toxicity are as follows (2):

  • Burning sensation in the mouth
  • Diarrhea
  • Nausea and/or vomiting

Severe symptoms of iodine toxicity are as follows: 

  • Weak pulse
  • Inflammation of the airways
  • Cyanosis
  • Coma

Excess consumption of iodine can also result in a condition known as iodine-induced hyperthyroidism. This typically occurs when a person takes iodine supplements to promote thyroid function.

Symptoms of hyperthyroidism are as follows (3):

  • Rapid heart rate
  • Weak muscles
  • Warm skin
  • Unexplained weight loss

Hyperthyroidism is extremely risky if you have an underlying heart problem as it affects the heart rate.

Causes of too much iodine 

Iodine toxicity typically develops from taking a lot of iodine supplements. It is very rare to get iodine toxicity solely from food. It must be noted that adults can tolerate around 1100 µg per day.

Large epidemiologic studies performed in the past decade in China, Turkey and Denmark suggest that supplementation with iodised salt increases the prevalence of autoimmune thyroid disease, be it clinical or subclinical hypothyroidism or autoimmune hyperthyroidism or both. These studies suggest that there should not be unnecessary supplementation with iodine (1).

Taking a single large dose of iodine usually does not result in iodine toxicity. However, the risk grows if a person constantly takes an excessive amount of iodine, the excess iodine confuses the thyroid, causing it to make excess thyroid hormone. 

This results in a drop in the secretion of thyroid hormone that typically prevails for almost 7 days.

Topical disinfectants, radiographic contrast agents and certain drugs contain large amounts of iodine in organic form. They have potentially the same effects as inorganic iodine, such as hyper- and hypothyroidism (1).

Particular medications can also increase the levels of iodine in the body. Amiodarone, a drug used to control heart rate and rhythm, consists of 75 mg of iodine in every 200 mg tablet. This is almost 100x higher than the standard recommended daily dose of 150 µg.

Older asthma syrups (may contain potassium iodide as a secretolytic). Iodpovidone, used for topical disinfection contains large amounts of iodine and may cause intoxication (1).

Risk factors for iodine toxicity

Even if a person does not take iodine supplements, some factors can make him more susceptible to iodine, which raises the chance of developing iodine toxicity. These include thyroid disorders, like:

If a person has undergone thyroidectomy, which removes all or part of the thyroid gland, he could become more susceptible to iodine, raising the chance of iodine toxicity.


In this brief article, we will answer the question, “How to counteract too much iodine?”. We will further elaborate on the symptoms and causes of too much iodine in the body as well as the risk factors for iodine poisoning. 


  1. Bürgi, Hans. Iodine excess. Best Pract Res Clin Endoc Metab, 2010, 24, 107-115.
  2. Liang, Han‐Yang, et al. Hypoxia, hypotension, and bradycardia induced by povidone‐iodine ingestion: A pediatric case report and literature review. J Am Coll Emerg Phys Open, 2020, 1, 1527-1529.  
  3. Okafor, Edwin Nkemjika, et al. Prevalence and pattern of thyroid disorders among patients attending University of Nigeria Teaching Hospital, Enugu, Southeastern Nigeria. Nig Med J: J Nig Med Assoc, 2019, 60, 62.
  4. Miller, D. W. Extrathyroidal benefits of iodine. J Am Phys Surg, 2006, 11, 106.