Daily Iodine Intake: How Much Iodine Do You Need?

By The DRI Calculator Team  |  Published: August 18, 2026  |  Updated: August 18, 2026  |  9 min read

Your daily iodine intake should be 150 micrograms for adults, and most people rely on salt to get it, which is exactly where a common and costly mistake creeps in. The catch is that not all salt contains iodine. Only salt specifically labelled iodized is fortified, while the sea salt, pink Himalayan, and kosher salt that have become fashionable contain almost none. Iodine is a trace mineral your thyroid cannot work without, and it matters most of all in pregnancy, when it shapes a baby's brain development. This guide gives the real numbers by age and life stage, clears up the salt confusion, names the best food sources, and explains why mild iodine deficiency is quietly making a comeback.

What Your Daily Iodine Intake Should Be

The recommendation comes from the Recommended Dietary Allowance set by the National Academies. For adults it is 150 micrograms of iodine a day, rising sharply to 220 micrograms in pregnancy and 290 micrograms while breastfeeding. Our guide to what DRI is explains how the RDA and the upper limit work together.

Iodine is a trace mineral the body cannot make, so it has to come from food or supplements. Its entire job centres on the thyroid gland, which uses iodine to produce the hormones that regulate metabolism, growth, and, crucially, brain development in early life. Because so few foods naturally contain much iodine, fortifying salt became the main way to protect whole populations from deficiency, which is the backdrop to the salt confusion this guide untangles.

Daily Iodine Intake by Age & Life Stage (Full Chart)

Iodine needs rise through childhood and settle at 150 micrograms from the teen years, the same for both sexes, then jump substantially for pregnancy and breastfeeding, the largest proportional increase of almost any mineral.

How much iodine do you need per day?

Adults need 150 micrograms of iodine a day, the same figure for men and women. Pregnancy raises the target to 220 micrograms and breastfeeding to 290 micrograms. Children aged 1 to 8 need 90 micrograms, and those aged 9 to 13 need 120 micrograms.

The Salt Myth: Not All Salt Contains Iodine

Here is the misunderstanding that catches out huge numbers of people. Iodine was added to table salt decades ago specifically to prevent deficiency across the population, and it worked so well that most people assume all salt is a source of iodine. It is not.

Best Food Sources of Iodine

Beyond iodized salt, the most reliable iodine comes from the sea and from dairy. Seafood concentrates iodine from seawater, and dairy picks it up through cattle feed and processing, which makes both dependable everyday sources.

Two cups of milk get you more than halfway to the adult target, and a serving of cod covers most of a day on its own. Seaweed is exceptionally rich but so variable, and sometimes so concentrated, that it is easy to overshoot, so it is best eaten in modest amounts rather than relied on as a daily megadose.

What Iodine Actually Does

Iodine has essentially one job, but it is a fundamental one: it is a building block of thyroid hormones. The thyroid combines iodine with the amino acid tyrosine to make the hormones that set the pace of metabolism throughout the body, influencing heart rate, body temperature, energy use, and weight regulation. Without enough iodine, the thyroid cannot make enough hormone, which leads to hypothyroidism and, often, a visible swelling of the gland called a goiter as it enlarges trying to capture more iodine. In early life the stakes are higher still, because thyroid hormone is essential for normal brain development, which is why iodine matters so much in pregnancy and infancy. Iodine works alongside selenium in the thyroid, which needs both minerals to convert thyroid hormone into its active form, a role covered in our guide to daily selenium intake.

Iodine in Pregnancy: Why It's Critical

If iodine matters at any point in life, it is during pregnancy and breastfeeding, which is why the target rises so sharply. The developing baby depends entirely on the mother's iodine to build the thyroid hormones that direct brain and nervous system development. Iodine deficiency during pregnancy is one of the leading preventable causes of intellectual impairment worldwide, and even mild shortfalls have been linked to effects on a child's cognitive development.

Is Iodine Deficiency Coming Back?

Iodized salt was one of the great public health successes of the twentieth century, largely eliminating widespread deficiency in many countries. But several modern trends are quietly eroding that protection. The shift to fashionable non-iodized salts like pink Himalayan and sea salt removes a source people assume they still have. Cooking more from scratch, while healthy in most respects, means less reliance on the processed foods that once contributed iodine, though those were never made with iodized salt anyway. And a move away from dairy, whether for dietary or ethical reasons, removes one of the most dependable everyday sources. The result is that mild iodine deficiency has been re-emerging in some groups, with studies finding a meaningful share of people, particularly women of childbearing age, falling below the estimated requirement. It is a reminder that a nutrient can slip back into shortfall when the habits that once delivered it change.

Can You Get Too Much Iodine?

Iodine follows the same pattern as its partner mineral selenium: both too little and too much cause thyroid problems. The tolerable upper intake level for adults is 1,100 micrograms a day, and a normal diet, even one using iodized salt generously, is very unlikely to approach it.

Who Needs to Watch Their Iodine

Most people who use iodized salt or eat dairy and seafood regularly meet their needs without thinking about it. Several groups should pay closer attention. Pregnant and breastfeeding women have much higher needs and are the priority group, as above, with the female picture across life stages covered in our guide to the DRI for women. People who use only specialty non-iodized salt, those who avoid dairy and seafood, and vegans are at higher risk of a shortfall and may need to seek out iodine deliberately. Anyone with a thyroid condition should manage iodine, in both directions, with their doctor rather than adjusting it alone.

How to Hit Your Daily Iodine Intake

For most people the fix is simple and cheap: use iodized salt rather than a specialty salt for everyday cooking, and the 150 microgram target largely takes care of itself alongside dairy, eggs, and the occasional serving of seafood. If you prefer sea or pink salt for flavour, that is fine, but make sure iodine comes from elsewhere in your diet. If you are pregnant, planning pregnancy, or breastfeeding, treat iodine as a priority and check that your prenatal supplement includes it. Reserve high-dose iodine and kelp supplements for situations a doctor has specifically recommended, since more is not better here.

The most useful starting point is your own number, since it depends on your age and life stage. Your full nutrient targets, iodine included, take only a moment to calculate.

Frequently Asked Questions