When you think of iodine, what comes to mind? Is it a brown bottle of antiseptic that stains your skin? Is it a container of table salt that doesn’t explain why it’s being iodized is a good thing? Or, maybe, it’s another face of this enigmatic chemical: the trace element in our bodies that does so much with so little.

What Is It?

Iodine is a chemical element, denoted using the ‘I’ symbol on the periodic table of elements. Rarely occurring naturally in foods [1], iodine is required by the body for proper function. Our bodies cannot make their own iodine; they must get all they need from outside sources.

What Is Its Biological Role?

Iodine’s primary role is to support thyroid function [2]. The thyroid is a very small but very important gland in the base of your neck. This gland produce hormones that have an effect on your body’s metabolism, energy levels, menstrual cycle, ovulation, weight, cognitive function, and more.

The thyroid uses these hormones to help you wake up and get going in the morning, digest your breakfast, keep you alert and focused, help regulate ovulation and menstruation, and prevent you from accumulating more fat than you should. Thyroid hormones cannot be produced without iodine.

If there is not enough iodine, the thyroid will typically swell in an attempt to glean for iodine from the rest of the body so that it can restore proper function. This is a condition known as goiter that typically presents itself as a swollen neck along with other symptoms.

In pregnant women, iodine also plays a major part in the neural development of the fetus. Iodine deficiencies in pregnant women have been linked to problems with cognitive development, sometimes severe.

How Can it Help Bodybuilders and People Who Work Out?

While most Americans are not clinically iodine deficient, many do barely scrape by in terms of adequate intake. As a result, they may experience minor symptoms of iodine deficiency and sub-optimal thyroid function that may hamper an intensive gym routine or reduce your results.

For instance, it may sap you of the energy you need to really give it your all in the gym. Or, it may prevent you from seeing results even if you do go all in when you work out. This is because part of the thyroid’s job is to prevent accumulation of body fat and water retention.

If you are barely getting enough iodine you may be experiencing these effects and simply mistaking them for a plateau in your fitness regime.

What Foods Contain It?

Certain foods specifically have iodine added to them, because it can be difficult to find a significant dietary source of iodine. A major example of this practice is iodized table salt. Not all table salt is iodized, only those varieties labelled as such.

Generally, however, most Americans will get almost all their iodine from using iodized salt. Some example of foods that naturally contain iodine are eggs, fish, and sea vegetables such as kelp.

How Much Of It Do You Need?

The recommended daily intake [3] for children varies as they age. For adults, the daily recommended amount is about 150mcg per day. For women who are pregnant or breastfeeding that number doubles, as a preventive measure to ensure the child receives an adequate supply of iodine for proper development in this sensitive stage.

Are There Risks Associated With Consuming Too Much Of It?

High levels of iodine in the body can negatively affect the thyroid just as much as low levels. This can result in goiter, and occasionally thyroid cancer.

Consuming very high doses of iodine all at once can also produce its own set of unpleasant symptoms, such as: burning of the mouth, throat, and stomach; nausea, vomiting, or other digestive discomforts; as well as a weak pulse or coma.

Are There Risks Associated With Consuming Too Little Of It?

Low levels of iodine in the body can cause hypothyroidism because the thyroid is unable to synthesize enough thyroid hormone. Symptoms of this can include fatigue, goiter, anxiety, brain fog, dry skin, and more.

It is also possible for low iodine levels to cause an autoimmune form of thyroid disease that causes the body’s immune system to attack and destroy the thyroid. Iodine deficiency in embryos or infants can cause stunted physical, cognitive, and sexual development.

It really is surprising how widespread the effects of iodine are within our bodies, especially for a substance our bodies are incapable of producing for themselves. Luckily, iodine deficiencies are becoming less common as more and more foods are being fortified with iodine to offset it’s relatively rarity in whole foods we would normally consume.

Dietary supplements of iodine are sometimes difficult to dose, but between increasing your intake of iodine-rich foods and choosing processed foods with iodine when available, you should have no problem reaping the benefits of this particular part of human physiology.


[1] Dr. Axe, Josh. Are You Eating Enough Iodine-Rich Foods?., 2016.

[2] Medline Plus. Iodine In Diet. National Library of Medicine, 2015.

[3] Office of Dietary Supplements, National Institute Of Health. Iodine- Consumer Fact Sheet. US Department of Health and Human Services, 2016.