Iodine is an essential trace mineral, meaning the body needs it to function properly. The body can’t produce it on its own – you must consume this mineral through the food you eat or as a supplement. While iodine is present in foods, the amounts present in food are hard to identify. Many people need to frequently use salt that’s enriched with iodine to get enough dietary doses.[i]
In the United States, iodized salt is the main source of this essential mineral. Iodine deficiency causes low levels of the thyroid hormone, which could lead to hypothyroidism. This isn’t a common problem, but it might occur in young children and infants. Lack of enough iodine is the leading cause of development and cognitive disabilities in different parts of the world.[ii] Also, apart from thyroid hormone production, iodine might play a significant role in other physical functions, but there is no enough evidence.
Iodine is an important part of thyroid hormones, which is the elements well-understood and most crucial function. The thyroid gland makes hormones triiodothyronine (T3) and thyroxine (T4), both contain iodine.[v]
Iodine is ingested orally and is quickly absorbed in the small intestine and stomach. It travels via the bloodstream, where iodine receptors bind to it. Following is a list of the ways through which iodine can benefit the body.
Promoting Thyroid Health
Iodine is known to play a significant role in improving thyroid health. The thyroid gland is located at the base of the neck, helps control hormone production. These are the hormones that control your heart health, metabolism, and more. Without sufficient iodine, your body can’t produce thyroid hormone.
Decreased Risk Of Goiter
Goiter is a swollen thyroid gland. The thyroid might become distended because of hyperthyroidism or hypothyroidism. Also, noncancerous thyroid nodules cause the enlargement of thyroid glands. Iodine deficiency is the most common cause of goiter around the world. However, it isn’t a common cause in the US and other nations with sufficient access to foods rich in iodine.[vi]
Improved Cognitive Function
The benefits of iodine during pregnancy might extend to a healthy brain for the children. It also includes decreased risks of intellectual disability.
Thyroid Cancer Treatment
Radioiodine might also be a great treatment option for thyroid cancer. This works similarly to the hyperthyroid treatment. If you take iodine orally, the drug destroys thyroid cells, including the cancerous ones. This might be used as a treatment after thyroid surgery to ensure all the cancerous cells have been eliminated from the human body. Other health benefits of iodine include:
- Protection from the nuclear fallout
- Disinfecting water
- It might help in the treatment of fibrocystic breast disease
- Improved birth weight
- Improved cognitive function
- Neurodevelopment during pregnancy
The most substantial effects of iodine deficiency involve problems in thyroid hormone production that ultimately causes symptoms of thyroid disease. If your body lacks enough iodine, signs of thyroid defects can develop within a few days and includes different health problems.
Insufficient iodine prevents the body from producing adequate thyroid hormones. This might cause a wide range of symptoms, including problems with blood sugar, menstrual irregularities, feeling cold regularly, depression, constipation, trouble concentrating, sleepiness, diminished energy, and weight gain.[iii]
Young children who lack enough iodine might experience similar consequences as adults and experience additional symptoms. These effects might be gradual and subtle, including learning difficulties, trouble concentrating, mood problems, and slow physical growth.
When lack of enough deficiency leads to low thyroid hormone levels, the pituitary gland makes more (TSH) thyroid-stimulating hormones to compensate for the reduced levels of thyroid hormones. The thyroid-stimulating hormone stimulates the thyroid gland to make and release T3 and T4. Excess thyroid-stimulating hormone over triggers the thyroid gland. As a result, the thyroid gland becomes more enlarged but cannot adequately function in iodine deficiency, a change known as goiter.
Newborn screening tests help detect iodine deficiency in newborns. This condition might cause infants to experience heart problems, weak muscle tone, and trouble eating.[iv]
Possible Side Effects
Generally, moderate consumption of iodine through dietary iodine consumption in food or iodized salt should not be an issue since iodine is easily removed through the urine. Nevertheless, you can ingest more iodine than the body can hold through supplements that contain higher iodine doses. Studies have associated iodine overdose with thyroid cancer, thyroiditis, hyperthyroidism, and goiter.[vii]
Children who consume an entire bottle of pills or adults with kidney disease who utilize supplements cannot properly remove excess iodine. Symptoms might include diarrhea, vomiting, and stomach upset.[viii]
Iodine Sensitivity And Allergies
Some studies have reported Sensitivities and allergies to iodine. The three iodine reactions include allergies to injected iodine, allergies to ingested iodine, and skin sensitivity.[ix]
Topical iodine that’s directly used on the skin can cause skin pain and redness. The reaction is self-limited and ultimately resolves itself within few hours.[x]
The allergic reactions to iodine are still a controversial subject. Seafood allergies have in the past been attributed to iodine, but today medical experts believe seafood allergies are caused by other components of seafood, but not necessarily iodine.
Many contrast materials injected for different imaging studies usually contain iodine. In most cases, people experience some allergic reactions to the contrast injection.[xi]
Dosage And Preparation
Iodized salt is salt with added iodine. Because thyroid hormones are continuously produced, all adults and children should regularly consume iodine. Nursing and pregnant women need high amounts of iodine to fully support the growing infant. The US Institute of Medicine produced the recommendations for the iodine amounts that a person should consume per day.[xii]
Recommended Daily Allowance
- Children – 90 mcg to 130 mcg
- Adults – 150 mcg
- Pregnant women – 220 mcg
Where To Get Your Iodine
Since salt is well enriched with iodine and the mineral is found in a wide variety of foods. You can also get your RDA for iodine from supplements. However, we don’t recommend using iodine supplements unless you have iodine deficiency diagnosed by a health physician.
Essentially, a low iodine diet is usually recommended for people with a thyroid disorder. If you are following low salt issues because of other health problems, you might have to take iodine supplements.
Iodine is an essential mineral that’s available in many types of food. The thyroid gland needs iodine to make thyroid hormones, which has numerous responsibilities in the body. Following are some of the foods that are rich in iodine.
- Seaweed: Seaweeds are great sources of minerals, vitamins, and antioxidants. Nonetheless, the amount significantly varies based on the type of seaweed, the region where it grew, and how it was prepared. The three most popular types of seaweed include nori, wakame, and Kombu kelp.
- Cod: Cod is a type of fish with a delicate texture and mild flavor. For example, 3 ounces of cod has about 63mcg-99mcg, or 42 – 66% of the RDA for iodine
- Dairy: One cup of milk provides between 59% and 112% of the RDA for iodine.
- Iodized Salt: Both uniodized and iodized salt are available in the United States. One ¼ teaspoon of iodized salt contains 71 mcg of iodine.
- Shrimp: Three ounces of shrimp has approximately 35 micrograms of iodine, which is about 23% RDA for iodine.
- Tuna: Tuna is a good iodine source; 3 ounces offer 17 micrograms, about 11% of RDA for iodine.
- Eggs: One egg contains a wide range of minerals and vitamins. It’s also a great source of healthy fats and protein. One egg contains 24 micrograms or 16% RDA for iodine.
When choosing an iodine supplement, there are different factors you should consider, including the dosage, ingredient content, quality, and price. Some supplement brands are pricier than others, but price should not necessarily be an indicator of the quality. In some countries, such as the US, supplements are not as thoroughly regulated as medications.
The best thing you can do is stick to options with supplements produced by renowned companies, which maintain higher manufacturing standards and regularly test their supplement’s potency and purity. It’s also important to inspect the label. If you find some products that you are avoiding, such as allergens, artificial sweeteners, animal products, or added sugars, ensure you check the list of supplement ingredients before buying.
What’s the main benefit of iodine?
Is iodine bad for you?
Why do doctors utilize iodine?
Does iodine kill infections?
Should I take iodine supplements?
- [i] American Thyroid Association. Iodine Deficiency. 2020.
- [ii] Eastman CJ, Zimmermann MB. The iodine deficiency disorders. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext. South Dartmouth, MA: MDText.com, Inc. Updated February 6, 2018.
- [iii] Kostoglou-athanassiou I, Ntalles K. Hypothyroidism – new aspects of an old disease. Hippokratia. 2010;14(2):82-87.
- [iv] U.S. National Library of Medicine. Congenital hypothyroidism. Updated February 11, 2020.
- [v] Ahad F, Ganie SA. Iodine, Iodine metabolism and Iodine deficiency disorders revisited. Indian J Endocrinol Metab. 2010;14(1):13-17.
- [vi] National Institutes of Health, Office of Dietary Supplements. Iodine. Updated July 9, 2019.
- [vii] Johnson LE. Iodine. Merck Manual Professional Version. Updated October 2018.
- [viii] Johnson LE. Iodine. Merck Manual Professional Version. Updated October 2018.
- [ix] Puchalski AR, Chopra IJ. Radioiodine treatment of differentiated thyroid cancer despite history of ‘iodine allergy’. Endocrinol Diabetes Metab Case Rep. 2014;2014:130084. doi:10.1530/EDM-13-0084
- [x] Murthy MB, Krishnamurthy B. Severe irritant contact dermatitis induced by povidone iodine solution. Indian J Pharmacol. 2009;41(4):199-200. doi:10.4103/0253-7613.56069
- [xi] Schabelman E, Witting M. The relationship of radiocontrast, iodine, and seafood allergies: a medical myth exposed. J Emerg Med. 2010;39(5):701-707. doi:10.1016/j.jemermed.2009.10.014
- [xii] National Institutes of Health, Office of Dietary Supplements. Iodine. Updated July 9, 2019.