Iodine: Not Enough, Too Much, and Why You Need to Regulate Your Supplements

by Jana Bounds

Like most things in life, there can't be a one-size-fits-all approach to iodine consumption. The levels needed depend on a number of variables, including age, gender, the supplements you take, if you double dose those supplements (we’re talking to our HBP Electrolyte Supplement double dosers) and if you have certain autoimmune diseases that impact the thyroid gland, like Graves’ disease or Hashimoto’s disease.  

Looking back into American history, iodine gained attention in the early 1920s. Children residing near the Great Lakes and in the Pacific Northwest experienced goiters (swollen necks) due to iodine deficiency, which was attributed to insufficient iodine levels in the soil of those regions. Moreover, these children often suffered from compromised brain development. 

The introduction of iodized salt brought about a significant change for most of the American population. In 1924, Morton developed iodized salt and made it available in stores, aiming to enhance the health of Americans. Subsequently, the Food and Drug Administration mandated that the salt packaging include the message: "This salt provides iodine, a necessary nutrient." 

Now, iodine deficiency only impacts around 5% of the U.S. population, although that number has been marginally increasing since 1950, influenced by dietary changes. Meanwhile, it remains one of the most common and most easily and inexpensively resolved nutrient deficiencies in the world, impacting around 2.2 billion people.  

Where Does Iodine Come From?  

Iodine can be found naturally in soil and seawater, and is present in fish, shellfish, dairy products, eggs, beef liver, chicken, fortified infant formula and foods like fortified breads and cereals. However, diets in many areas—particularly in Europe and Third World countries where the soil and food supply have low iodine levels—can’t provide adequate iodine without offering salt fortified with iodine.  

“It is estimated that about 2 billion people suffer from iodine deficiency in the world, and the real tragedy is that the condition is so readily preventable. Addition of potassium iodate to salt is the simple solution,” according to McGill Office for Science and Society, noting how it can be accomplished inexpensively.  

Why is Iodine So Important? 

Iodine is an indispensable nutrient with profound implications for thyroid gland function. The thyroid gland, responsible for synthesizing thyroxine (T4) and triiodothyronine (T3), relies on iodine as an essential component in the production of these hormones. In fact, T4 is actually a molecule with four iodine in it and T3 is the same molecule with three iodine in it. The thyroid reduces T4 to T3 under normal healthy conditions.  

The rate at which T4 is converted to T3 helps us see if the thyroid is healthy and can maintain proper metabolic rate, ensuring the correct functioning of many organs in the body.  

Iodine is important for everyone, but people with certain conditions and those supplementing with iodine should carefully manage and monitor their intake. We will discuss the specifics below.  

Iodine Deficiency and Toxicity 

Inadequate dietary iodine intake gives rise to iodine deficiency. This is especially concerning during pregnancy and early childhood where insufficient iodine can adversely affect neurodevelopment, leading to cognitive impairments and developmental delays.  

In adults, iodine deficiency manifests as hypothyroidism, characterized by symptoms such as fatigue, weight gain, cold intolerance, and cognitive impairment. It may also be represented by breast pain, a rather frequent complaint of many women. 

Iodine excess, or toxicity, can lead to thyroid glands producing too much T4 and T3, leading to hyperthyroidism.  

Diseases That Increase Iodine Sensitivity 

Is it Possible to Get Iodine Poisoning?  

Yes, it typically affects people who take too many iodine supplements, or a number of supplements that contain iodine, or those who have a hyperthyroid condition. Adults without thyroid conditions can tolerate up to 1,100 mcg of iodine per day.  

Iodine poisoning is serious, typically resulting in a hospital visit where the physicians may make the person vomit or take activated charcoal to prevent the body from absorbing more iodine. If the iodine poisoning is severe, the breathing can be impacted until the iodine levels decrease, which may take some time, during which the person may have to be on a ventilator. Mild cases of iodine poisoning can typically be resolved without lasting issues, particularly with expedient medical treatment. Still, some cases can have lasting implications, like a permanent narrowing of the windpipe.  

Look at the Labels and Talk to Your Doctor 

It’s important to be mindful of the supplements you take, and how much of them you are taking, to make sure you aren’t ingesting too much iodine. Although iodine is an essential nutrient, too much can disrupt your thyroid function and cause an imbalance. Be mindful that some multivitamins contain iodine. And don’t forget that you likely already have iodine in your diet, especially if you consume iodized salt.  

Consult with a healthcare professional or registered dietitian if you are taking iodine supplements or any supplements that contain iodine, so they can give you more personalized guidance on the levels you need.