Iodine (Elemental I) vs. Iron (Heme & Non-Heme)
Comparing 2 standards across 9 specifications. 9 key differences identified.
Iodine is an essential halogen trace element required exclusively as an essential structural component of thyroid hormones thyroxine (T4) and triiodothyronine (T3), regulating metabolic rate, cellular respiration, and fetal neurodevelopment. Adult RDA is 150 µg, with an Upper Limit of 1,100 µg/day.
Iron is an essential redox trace element central to hemoglobin oxygen transport, myoglobin storage, and mitochondrial electron transport chain cytochromes. Adult RDA is 8mg (men/post-menopausal women) / 18mg (pre-menopausal women), with a Tolerable Upper Limit of 45mg/day.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nutrient Type
|
Essential Trace Halogen Element | Essential Trace Mineral |
|
Adult RDA / RDI
|
150 µg / day (220 µg pregnancy / 290 µg lactation) | 8 mg (Men) / 18 mg (Women 19–50) / 27 mg (Pregnancy) |
|
Tolerable Upper Limit (UL)
|
1,100 µg / day (Avoid Wolff-Chaikoff thyroid autoregulatory shutdown) | 45 mg / day (Hemochromatosis / Fenton reaction oxidative stress) |
|
Chemical Forms
|
Iodide (I- / Potassium Iodide KI, Potassium Iodate KIO3 in iodized salt), Molecular Iodine | Heme Iron (Fe2+ Porphyrin - Animal), Non-Heme Iron (Fe3+ Ferric / Fe2+ Ferrous - Plants/Supplements) |
|
Primary Biological Function
|
Constituent of Thyroxine (T4, 4 iodine atoms / 65% by weight) and Triiodothyronine (T3, 3 iodine atoms / 59% by weight) | Hemoglobin O2 transport, Myoglobin O2 storage, Cytochrome c electron transport, Catalase |
|
Deficiency Condition
|
Endemic Goiter (Compensatory thyroid enlargement), Congenital Hypothyroidism / Cretinism (Permanent neurodevelopmental impairment), Maternal miscarriages | Microcytic Hypochromic Anemia, Severe fatigue, Restless legs syndrome, Pica |
|
Top Whole Food Sources
|
Kombu Kelp, Nori Seaweed, Atlantic Cod, Eastern Oysters, Iodized Table Salt, Greek Yogurt, Dairy Milk, Eggs | Beef Liver, Oysters, Duck Breast, Beef Ribeye, Lentils, Spinach, Dark Chocolate |
|
Iodized Salt Public Health Impact
|
Universal salt iodization (45–75 mg KI / kg salt) is hailed as one of the greatest global public health achievements, eradicating cretinism worldwide | — |
|
Bioavailability Difference
|
— | Heme: 15–35% absorption (uninhibited); Non-Heme: 2–20% (inhibited by phytates/calcium, boosted by Vitamin C) |