What it does in the body
- Thyroid hormone synthesis (T3 and T4)
- Basal metabolic rate regulation
- Fetal and infant brain development
- Thermogenesis (body temperature regulation)
- Growth and maturation
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 150 mcg | WHO/IOM |
| Adult female | 150 mcg | WHO/IOM |
| Pregnancy | 220-250 mcg | WHO/IOM |
| Children | 90 mcg (1-8y), 120-150 mcg (9-18y) | WHO/IOM |
| Older adults | 150 mcg | WHO/IOM |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Seaweed (kelp) | 2000-3000 mcg per 100g (variable) | East Asia |
| Cod | 170 mcg per 100g | North Atlantic |
| Iodized salt | 77 mcg per 1g salt | global |
| Shrimp | 35 mcg per 100g | coastal regions |
| Milk (dairy) | 50-80 mcg per 100ml | global |
| Eggs | 24 mcg per 100g | global |
| Tuna (canned) | 17 mcg per 100g | global |
| Nori (seaweed sheet) | 1400 mcg per 100g | Japan/Korea |
If you don't get enough
Mild: Subclinical hypothyroidism, mild goiter, fatigue
Moderate: Goiter, hypothyroidism, impaired cognitive function, weight gain, menstrual irregularities
Severe: Cretinism in offspring (severe intellectual disability, deaf-mutism, motor spasticity), myxedema, massive goiter, increased pregnancy loss
Time to onset: Goiter: months to years. Cretinism: irreversible damage occurs in first trimester of pregnancy.
Too much
Upper limit: 1100 mcg/day (adults)
Thyroiditis, hyperthyroidism (Jod-Basedow) or hypothyroidism (Wolff-Chaikoff), metallic taste, burning mouth, GI upset. Chronic excess may trigger autoimmune thyroid disease.
How well you absorb it
>90% absorbed as iodide from GI tract
Helped by: Selenium (required for thyroid deiodinase enzymes), Adequate protein intake
Hindered by: Goitrogens (thiocyanate from cruciferous vegetables, cassava), Perchlorate (environmental contaminant), Nitrate (competes for NIS transporter), Soy isoflavones (inhibit thyroid peroxidase)
Cooking & storage
Iodized salt loses iodine with prolonged storage, heat, and humidity. Cooking with iodized salt retains 20-60% of iodine depending on method and duration. Boiling seaweed extracts most iodine. Goitrogenic activity of cruciferous vegetables is reduced by cooking.
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
