Minerals

Iodine

The thyroid mineral that regulates your metabolism.

~30% of the global population lives in iodine-deficient areas; iodized salt has reduced but not eliminated deficiency in the US

Why it matters for longevity

Iodine is required for the synthesis of thyroid hormones T3 and T4, which regulate metabolism, growth, and development. Even mild iodine deficiency can impair thyroid function, leading to fatigue, weight gain, and cognitive sluggishness. Thyroid dysfunction accelerates aging and increases cardiovascular risk. Globally, iodine deficiency remains the leading preventable cause of intellectual disability.

How much you need

RDA

150mcg for adults, 220mcg for pregnant women

Optimal

Researchers recommend 150-250mcg daily, with higher needs during pregnancy and lactation.

Signs you might be low

  • Unexplained weight gain
  • Fatigue and sluggishness
  • Feeling cold when others are comfortable
  • Dry skin and hair loss
  • Swelling in the neck (goiter)

Best food sources

FoodPer serving
Seaweed, dried (1g)16-2,984mcg (varies widely)
Cod (3 oz)99mcg
Iodized salt (1/4 tsp)71mcg
Yogurt, plain (1 cup)75mcg
Shrimp (3 oz)35mcg

Key research

Zimmermann MB, Boelaert K (2015). Iodine deficiency and thyroid disorders. The Lancet Diabetes & Endocrinology, 3(4), 286-295.

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