Minerals
Iodine
An essential trace mineral crucial for thyroid hormone production, metabolism regulation, and brain development
Quick Facts
Daily Needs
150 mcg for adults, with higher needs during pregnancy (220 mcg) and lactation (290 mcg)
Importance
Iodine is essential for thyroid hormone synthesis, which regulates metabolism, growth, development, and brain function.
Key Functions
- •Thyroid hormone production (T3 and T4)
- •Regulation of metabolic rate
- •Energy production
- •Body temperature regulation
- •Brain development and cognitive function
- •Growth and development
- •Reproductive health
- •Immune system support
- •Antioxidant activity
- •Protein synthesis
Deficiency Signs
- •Goiter (enlarged thyroid gland)
- •Hypothyroidism
- •Fatigue and weakness
- •Weight gain
- •Dry skin and hair
- •Hair loss
- •Cold sensitivity
- •Muscle pain and weakness
- •Depressed mood
- •Memory impairment
- •Slower heart rate
- •In pregnancy: risk of miscarriage, stillbirth, congenital abnormalities
- •In children: impaired growth and cognitive development (cretinism)
Excess Signs
- •Thyroid dysfunction (both hyper- and hypothyroidism)
- •Burning of the mouth, throat, and stomach
- •Fever
- •Nausea and vomiting
- •Diarrhea
- •Weak pulse
- •Thyroid inflammation
- •Acne-like skin lesions
- •Increased risk of thyroid cancer with chronic excess
Best Food Sources
- •Seaweed (especially kelp, nori, and kombu)
- •Iodized salt
- •Seafood (cod, shrimp, tuna)
- •Dairy products (milk, yogurt, cheese)
- •Eggs
- •Enriched bread and grain products
- •Cranberries
- •Strawberries
- •Potatoes with skin
- •Turkey and chicken
- •Prunes
Absorption Facts
- •Absorption occurs primarily in the small intestine
- •About 90% of ingested iodine is absorbed
- •Vitamin A is needed for proper iodine utilization
- •Certain foods contain goitrogens that can interfere with iodine uptake
- •Bromide, chlorine, and fluoride can compete with iodine for absorption
- •Selenium is required for thyroid hormone production
- •Excessive calcium intake may decrease iodine absorption
- •Most absorbed iodine is excreted in urine
Special Considerations
- •Pregnant and breastfeeding women have significantly higher iodine requirements
- •Vegans and those who avoid iodized salt may be at higher risk for deficiency
- •People living in regions with iodine-poor soil need to be more mindful of intake
- •Certain medications can affect iodine metabolism (amiodarone, lithium)
- •Those with autoimmune thyroid disorders should consult healthcare providers about iodine intake
- •Cruciferous vegetables and soy contain goitrogens that can inhibit thyroid function in large amounts
- •Iodine needs may increase during periods of growth or high metabolic demand
- •The margin between adequate intake and excess is relatively narrow
About Iodine
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