{"id":46666,"date":"2024-02-09T10:00:00","date_gmt":"2024-02-09T18:00:00","guid":{"rendered":"https:\/\/foodrevolution.org\/?p=46666"},"modified":"2026-09-14T06:08:23","modified_gmt":"2026-09-14T13:08:23","slug":"how-much-iodine-do-you-need","status":"publish","type":"post","link":"https:\/\/foodrevolution.org\/blog\/how-much-iodine-do-you-need\/","title":{"rendered":"How Much Iodine Do You Need? Sources and Strategies for Optimal Health"},"content":{"rendered":"

It\u2019s the early part of the 19th century. Napoleon is trying to conquer Europe. England is trying to stop him. And everybody needs gunpowder.<\/p>\n

Turns out there\u2019s no such thing as a gunpowder mine (thank heavens for small mercies), so the stuff had to be manufactured. And one of the waste products of this process was giant piles of violet-colored solids.<\/p>\n

A French chemist, Bernard Courtois, whose father was a saltpeter manufacturer, was the first to suspect that this violet stuff was an as-yet-undiscovered chemical element. When this discovery was confirmed, the new element was named iodine<\/a>, after the Greek word for violet: ioeid\u0113s.<\/p>\n

It\u2019s a pretty rare element in the universe and on Earth (which I\u2019m guessing is where most of my readers live), with the greatest concentrations found in the oceans. But it\u2019s crucial for the health of all vertebrates because it\u2019s necessary for the functioning of the gland responsible for energy production: the <\/span>thyroid<\/span><\/a>.<\/span><\/p>\n

Iodine deficiency<\/a> is less of a problem these days because of global public health campaigns to add the nutrient to table salt (that\u2019s what \u201ciodized\u201d means on the label), but it still affects up to 30% of the world\u2019s human population.<\/strong><\/p>\n

If you consume iodized salt, you\u2019re almost certainly getting enough iodine. But a lot of salt sold in natural foods stores, such as Himayalan and Celtic sea salt, only contains trace amounts<\/a> of naturally occurring iodine \u2014 if any. And if you choose to avoid added sodium as part of an \u201cSOS-free<\/a>\u201d diet (that is, free of added salt, oil, and sugar), you may want to consider getting your iodine from other sources.<\/p>\n

The thing is, though, that both too much and too little iodine can be problematic. So how much iodine do you need? What are the best sources? And how can you avoid excess or deficiency?<\/p>\n

What Is Iodine?<\/h2>\n
\"Highlight
iStock.com\/HT Ganzo<\/figcaption><\/figure>\n

Iodine is an essential micronutrient that\u2019s necessary for human health. Even though you only need a small amount, you do need iodine from food or supplements because the body doesn\u2019t make its own.<\/p>\n

The thyroid gland<\/a>, a small, butterfly-shaped organ located in the front of the neck, needs iodine to produce the hormones thyroxine (T4) and triiodothyronine (T3), which play several critical roles in your body.<\/strong><\/p>\n

T4 and T3 are important for metabolism, the body\u2019s process of turning food into energy. They help maintain<\/a> the body\u2019s temperature, heart rate, and energy levels. They\u2019re also necessary<\/a> for proper bone and brain development during pregnancy and infancy.<\/p>\n

Iodine can be the limiting factor in the thyroid\u2019s hormone factory. When you don\u2019t get enough iodine, your thyroid can become underactive, a condition known as hypothyroidism<\/a>. At the same time, too much iodine can cause the thyroid gland to go into overdrive, a condition called hyperthyroidism. We\u2019ll look at both of these conditions in more detail below.<\/p>\n

If you find yourself getting confused about hypo- and hyperthyroidism, here\u2019s a quick Greek lesson. \u201cHypo\u201d means \u201ctoo little\u201d or \u201cunder.\u201d For example, hypothermia means \u201ctoo little heat,\u201d and a hypodermic needle injects \u201cunder the skin.\u201d \u201cHyper,\u201d on the other hand, means \u201ctoo much.\u201d For instance, hyperactivity describes overly active behavior, and a \u201chyperbole\u201d is an exaggeration.<\/p>\n

How Much Iodine Do You Need?<\/h2>\n

Iodine is known as a \u201ctrace\u201d mineral since you need only a small amount. The US Recommended Daily Allowances (RDAs) are considered the \u201cfloor\u201d \u2014 the minimum quantity needed for health. You might think that more is better, but as I mentioned earlier, it\u2019s also easy to get too much. You want just the right amount. (Think \u201cGoldilocks\u201d \u2014 although now that I do, what\u2019s the deal with Papa Bear\u2019s porridge being too hot and Mama Bear\u2019s being too cold? How does that happen?)<\/p>\n

Here are the iodine RDAs<\/a>:<\/strong><\/p>\n\n\n\n\n\n\n\n\n\n
Age<\/b><\/td>\nRDA<\/b>(mcg\/day)<\/td>\nPregnancy<\/b>(mcg\/day)<\/td>\nLactation<\/b>(mcg\/day)<\/td>\n<\/tr>\n
Birth to 6 months<\/td>\n110<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
7\u201312 months<\/td>\n130<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
1\u20133 years<\/td>\n90<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
4\u20138 years<\/td>\n90<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
9\u201313 years<\/td>\n120<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
14+ years<\/td>\n150<\/td>\n220<\/td>\n290<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

That \u201cmcg\u201d is short for microgram, which is one-millionth of a gram. If you picture cutting a single paperclip (regular size, not a \u201cjumbo\u201d one) into a million pieces, each of those pieces would weigh roughly one microgram. (Fun fact: If each cut took five seconds, you would need nearly two months of nonstop snipping to get the job done.)<\/p>\n

Iodine Deficiency<\/h3>\n
\"Asian
iStock.com\/sasirin pamai<\/figcaption><\/figure>\n

As we\u2019ve seen, not getting enough iodine in the diet results in iodine deficiency, which can cause iodine deficiency disorders<\/a> (IDDs). One of these is goiter<\/a>, or an enlargement of the thyroid. When your pituitary gland notices a shortage of thyroid hormones, it sends a message to the thyroid to increase production. The thyroid gland tries to compensate by increasing its activity.<\/p>\n

In the absence of sufficient iodine, however, this increased activity, instead of bringing the hormones to their proper levels, causes an enlarged thyroid<\/a> <\/strong>that can make it difficult to swallow, cough, and even breathe.<\/p>\n

Even without goiter, not enough iodine can cause the thyroid gland to be underactive, a condition known as hypothyroidism. In this condition, the body\u2019s iodine levels decrease, keeping your thyroid from producing enough thyroid hormones. Your metabolism slows, and accompanying symptoms can include<\/a> fatigue, weight gain, cold intolerance, infertility, and depression.<\/p>\n

Prior to the 1920s, iodine deficiency was prevalent in the Great Lakes, Appalachians, and Northwestern regions of the US, an area that came to be known as the \u201cgoiter belt<\/a>.\u201d A survey conducted in Michigan in 1923 found that in some regions, around 60% of the population<\/a> suffered from goiters, including children.<\/p>\n

This finding led to a concerted public health campaign to add iodine to the food supply. The campaigners hit upon salt as the simplest, most effective delivery mechanism for the mineral.<\/p>\n

The implementation of these salt-iodization programs worldwide has reduced the incidence of iodine deficiency, but 30% of the world\u2019s population is still at risk<\/a>. Mild to moderate iodine deficiency not only remains common but appears to be increasing<\/a>, especially during pregnancy, when needs are the highest.<\/strong><\/p>\n

In pregnancy, iodine deficiency is defined<\/a> as an iodine level in the urine of less than 150 mcg\/L. In those who are not pregnant, it\u2019s less than 100 mcg\/L of urine.<\/p>\n

Iodine Excess<\/h3>\n

So if not enough iodine is a problem, then surely the solution is to consume lots of it, right? Well, not so fast. Too much iodine can also cause problems. Ironically, many of the symptoms of excess iodine are the same as those of deficiency, such as goiter, elevated TSH levels, and hypothyroidism.<\/strong><\/p>\n

And if too much iodine is administered to treat iodine deficiency, that can lead to hyperthyroidism<\/a>, or overactive thyroid. Basically, your body\u2019s metabolism goes into overdrive, producing symptoms such as nervousness and anxiety, mood swings, difficulty sleeping, frequent urination, persistent thirst, muscle weakness, fatigue, and sensitivity to heat.<\/p>\n

Too much iodine intake can cause thyroiditis (inflammation of the thyroid; the Greek suffix \u201citis\u201d means inflammation) and even thyroid papillary cancer, which is the most common form of thyroid cancer.<\/p>\n

Acute iodine poisoning is rare because few foods have enough iodine to cause it, but it is possible through excess supplementation. Symptoms<\/a> include burning of the mouth, throat, and stomach, fever, abdominal pain, and even coma.<\/p>\n

To avoid iodine poisoning when taking supplemental iodine, the US Food and Nutrition Board has identified<\/a> the following safe Upper Limits (ULs) for the mineral:<\/strong><\/p>\n