How Much Iodine is Too Much?

How Much Iodine is Too Much?

Do you know how much iodine you’re getting daily? While most of us get enough of this mineral from eating a balanced diet, there are a few groups who run a higher risk of developing an iodine deficiency than others. For this reason, it’s important to know where we fall in terms of how much we need to keep our bodies healthy. 

The amount of iodine our bodies need depends on our age and stage of life. The average adult needs 150mcg of iodine, while certain demographics such as pregnant women need more.

In this article, we’ll break down exactly how much iodine you need depending on who you are. For an in-depth explanation of why some of us need more than others, including a breakdown of which groups may experience more serious symptoms from a deficiency than others, we’ve got everything you need to know. 

Are you getting enough iodine?

The table below provides answers as to how much iodine the following groups should be intaking daily:

Life Stage

Recommended Amount of Iodine (per day)

Birth to 6 months

110 mcg

Infants 7-12 months

130 mcg

Children 1-8 years

90 mcg

Children 9-13 years

120 mcg

Teens 14-18 years

150 mcg


150 mcg

Pregnant teens and women

220 mcg

Breastfeeding teens and women

290 mcg

Data from the National Institutes of Health 

While this table tells us how many mcg of iodine we need based on the above factors, let’s take it one step further and discuss why these discrepancies exist.

Why do infants need iodine?

From the time of birth to about 12 months, infants need between 110-130mcg of iodine per day. This makes them one of the groups with the highest daily recommended intake.

Why? Iodine is necessary to ensure healthy growth and development. Newborns are constantly growing, and those who are not receiving the recommended intake of iodine could experience the following symptoms:

  • Hypothyroidism
  • Damaged nervous system
  • Impaired neurodevelopment
  • Death  

For infants, the long-term side effects of an iodine deficiency can be permanent, making this group one of the most important to be receiving the right amount. 

So where does their iodine intake come from? Infants can receive iodine from their mother’s breast milk or through special formula. 

Why do children need iodine?

Children between the ages of one to eight years need 90mcg of iodine while children between the ages of nine need 120mcg. 

Much like infants, children need iodine in their diets to support their growth and development. 

Children failing to receive their recommended daily intake of iodine could experience the following symptoms:

  • Swelling of the neck (goiter)
  • Fatigue
  • Weight gain
  • Hair loss
  • Cognitive impairment
  • Reduced motor function
  • Hypothyroidism

If children are unable to receive the right amount of iodine for a long time, symptoms like cognitive impairment can become permanent.

Why do teens and adults need iodine?

Teens and adults need a daily intake of 150mcg of iodine for optimal brain and bone health.

In the case of a deficiency, the thyroid gland is unable to produce hormones that support these functions. 

Teens and adults are prey to the same symptoms children experience if less than the recommended amount of iodine is being consumed, including long-term effects like cognitive impairment.

Why do pregnant women need iodine?

Pregnant women need 220mcg of iodine daily to support their bodies and developing fetuses. 

This category has one of the highest recommended amounts of daily intake because a pregnant woman’s thyroid gland is working overtime - it needs to produce enough hormones for two.

Therefore, pregnant women are considered a higher risk category for developing an iodine deficiency. 

Some risks of an iodine deficiency in pregnant women include not only the same symptoms as any other adult but also:

  • Maternal and fetal hypothyroidism
  • Maternal and fetal goiter
  • Congenital anomalies
  • Cretinism

Why do breastfeeding teens and women need iodine?

Breastfeeding teens and women need 290mcg of iodine, making them the category with the highest recommended intake. Why is this?

We already mentioned that infants receive their iodine intake from breast milk - this is why mothers must provide their infants a concentration of breast milk with higher maternal iodine levels.

One study concluded that based on how much iodine infants need in conjunction with the volume of breast milk they typically drink, almost half of women are not providing their infants with enough iodine.

This exemplifies why breastfeeding teens and women are the groups in need of the most daily iodine intake - they need enough to support not only the functioning of their thyroid but the growth and development of their infants too.

Other groups at risk of an iodine deficiency

Vegans and vegetarians

Because there are very few plant-based sources rich in iodine, vegans and vegetarians are at risk of not consuming enough. This demographic may need to take vegan iodine supplements to get their recommended daily amount.

Anyone choosing sea salt vs iodized salt

One way many of us increase our daily intake of iodine is through our consumption of iodized salt or everyday table salt. If anyone chooses to use sea salt instead and fails to get enough iodine from other food sources, he or she may be more likely to suffer from an iodine deficiency. 

For more information on how at-risk groups can increase their intake of iodine, check out our guide to iodine and thyroid health: Are You Getting Enough Iodine? A guide to thyroid health

What happens if we get too much iodine?

While it’s important to make sure we’re getting enough iodine every day, it can be equally as important to make sure we aren’t getting too much.

Overconsumption of iodine can result in the following:

  • Thyroid gland inflammation
  • Thyroid cancer
  • Stomach pain
  • Nausea 
  • Vomiting
  • Diarrhea

How to test for an iodine deficiency 

If you’re concerned you may be suffering from an iodine deficiency, there are various tests your doctor can perform.

These tests can be done via a urine sample, blood sample, or an iodine patch test.

Parting thoughts on iodine intake

Because the amount of iodine we’re meant to consume daily depends on several factors, the best we can do is stay informed regarding how much we need and why. 

If you are in any of the at-risk categories for an iodine deficiency, it’s time to make sure you’re doing everything you can to keep your thyroid glands healthy and happy.

Trusted Sources

  1. Iodine. Fact Sheet for Consumers. National Institutes of Health. Office of Dietary Supplements.
  2. Pearce, EN, Leung AM, Blount BC, Bazrafshan HR, He X, Pino S, Valentin-Blasini L, Braverman LE. Breast milk and iodine and perchlorate concentration in lactating Boston-area women. J. Clin Endocrinol Metab. 2007.
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