Original of this article was published on ZRT Laboratory Blog. Last reviewed: May 2026.
Why the Need for Iodine?
Iodine is an essential component of thyroid hormone (T3 & T4) and important for normal thyroid functioning. It also functions as an antioxidant, an anti-infective agent, and is protective in certain cystic conditions like fibrocystic breast disease and ovarian cysts.
Higher levels of iodine intake have been shown to be protective against benign breast changes such as fibrocystic breast disease. Studies show a daily intake of 3,000–6,000 micrograms per day to be helpful and tolerable for this condition — levels similar to the typical daily intake seen in Japan.
To make sure our bodies are sufficient in iodine, we can eat foods high in iodine and/or take an iodine supplement. Many people assume all seaweeds have a lot of iodine, but there is a great deal of variability. Kelp has the most, and nori has the least — meaning your weekly nori roll at the sushi restaurant may not be giving you sufficient iodine.
If you are concerned about your iodine status and its impact on thyroid function, our Thyroid & Iodine Test Kit measures both thyroid markers and urinary iodine from a simple at-home sample — giving a clear picture of whether iodine deficiency may be contributing to thyroid dysfunction.
Recommended Daily Allowances for Iodine
The Recommended Daily Allowance (RDA) for iodine is 150 micrograms per day for proper thyroid functioning in adults. Requirements increase significantly during pregnancy and breastfeeding:
- Adults: 150 micrograms/day
- Children: 90–120 micrograms/day
- Pregnant: 220 micrograms/day
- Breastfeeding: 290 micrograms/day
For those who want to confirm their iodine levels directly, our ICPMS Iodine & Creatinine Test Kit measures urinary iodine and creatinine — the most reliable method for assessing iodine sufficiency in the body.
Dietary Sources of Iodine
Below is a guide to the amount of iodine found in common foods and supplements (values in micrograms):
Seaweeds
1 tsp Kelp: 3,400 | 1 tbsp Arame: 730 | 1 tbsp Wakame: 80 | 1 sheet Nori: 32
Fish & Seafood
3 oz Cod: 341 | 3 oz Shrimp: 79 | 3 oz Halibut: 56 | 3 oz Herring: 56 | 3 oz Sardines: 30 | 3 oz Tuna: 17
Salt
1 tsp Iodised salt: 76
Dairy
1 cup cow’s milk (US): 56 | 1 oz mozzarella cheese: 10 | 1 cup yogurt: 87
Other Foods
3 oz turkey breast: 34 | 1 cup strawberries: 12 | 1 egg: 23
Supplements
1 tablet Iodoral™: 12,000 | 1 drop Lugol’s™ 5%: 6,250 | 1 typical multivitamin dose: 150
If you are experiencing symptoms of thyroid dysfunction — such as fatigue, weight changes, hair loss or cold intolerance — our Thyroid Test Kit measures TSH, T3 and T4 with a specialist doctor report included, helping to identify whether iodine deficiency or another thyroid imbalance may be at the root of your symptoms.