Iodine

Needed to make thyroid hormones, which control metabolism and, in pregnancy, baby brain development.

If you are short of it

Goitre and hypothyroidism

Swollen thyroid, tiredness, feeling cold, weight gain; in pregnancy it can harm baby brain development.

Possible signs

Swelling at the front of the neck
Feeling cold, slowed down
Tiredness, low energy
Poor memory or concentration
Dry, flaky skin
Hair thinning or loss
Slow growth in children

These signs are common and have many other causes. They are clues, not proof; a blood test and a doctor can tell.

Who is more at risk

Pregnant and breastfeeding women, people who avoid iodised salt, dairy and fish, regions with iodine-poor soil.

Foods rich in Iodine

Food	Serving	Amount	women 19–50	men 19–50
Cod or other white fish	100 g cooked	172 NIH	115%	115%
Seaweed (nori)	2 tablespoons flakes (5 g)	116 NIH	77%	77%
Plain yogurt (low-fat)	1 cup (245 g)	87 NIH	58%	58%
Milk (fortified)	1 cup (240 ml)	85 NIH	57%	57%
Iodised salt	¼ teaspoon	78 NIH	52%	52%
Eggs	2 large eggs	62 NIH	41%	41%
Cheese (cheddar type)	40 g, about 2 slices	20 NIH	13%	13%
Beef liver	85 g cooked	14 NIH	9.3%	9.3%
Shrimp	85 g cooked	13 NIH	8.7%	8.7%
Tuna (canned, light)	85 g, half a can	7 NIH	4.7%	4.7%

Unit: mcg. Share of the daily amount. Values marked NIH were checked against the food tables of the NIH Office of Dietary Supplements; the others are approximate and unchecked. Real foods vary with variety, brand, soil and cooking.

Plan a day of meals rich in Iodine

As a supplement

Potassium iodide in supplements. Kelp supplements vary enormously in iodine content and can be very high.

Too much

Both too little and too much iodine can cause goitre and thyroid problems. People with thyroid disease should ask their doctor before supplementing.

How much you need each day

Group	Recommended	Upper limit
Infants 0–6 months	110	—
Infants 7–12 months	130	—
Children 1–3 years	90	200
Children 4–8 years	90	300
Children 9–13 years	120	600
Boys 14–18 years	150	900
Girls 14–18 years	150	900
Men 19–30 years	150	1100
Women 19–30 years	150	1100
Men 31–50 years	150	1100
Women 31–50 years	150	1100
Men 51–70 years	150	1100
Women 51–70 years	150	1100
Men over 70	150	1100
Women over 70	150	1100
Pregnant 14–18 years	220	900
Pregnant 19–30 years	220	1100
Pregnant 31–50 years	220	1100
Breastfeeding 14–18 years	290	900
Breastfeeding 19–30 years	290	1100
Breastfeeding 31–50 years	290	1100

Unit: mcg. US/Canada Dietary Reference Intakes (National Academies), as summarised by the NIH Office of Dietary Supplements. Other countries’ values differ slightly. These are amounts for healthy people, not treatment doses.

Interactions

Take care · Selenium
Selenium is needed to turn thyroid hormone into its active form. Both iodine and selenium matter for the thyroid, and too much of either can upset it.

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General information for healthy people. It does not diagnose, treat or replace advice from a doctor, pharmacist or dietitian. Not reviewed by a clinician.

Page updated: 2026-10-08 · By Prof. E. Shalaan, Applied Sciences and AI (ASAI)