How Much Iodine Do You Really Need?
Iodine is essential for thyroid hormones (T3, T4) and fetal brain development. According to the CDC and the NIH Office of Dietary Supplements (ODS), the US RDA is 150 mcg/day for adults, rising to 220 mcg during pregnancy and 290 mcg while breastfeeding — the same thresholds endorsed by the American Thyroid Association (ATA) for US clinicians. Iodized table salt (FDA-permitted at 45 mcg per ¼ tsp) has been the main US dietary source since the 1920s, but mild deficiency has reappeared among Americans choosing Himalayan pink, sea, or kosher salt (typically not iodized) and those cutting sodium. This calculator returns your target intake by life stage and lists the best US food sources: iodized salt, seafood, dairy, and prenatal vitamins.
When to use this calculator
- Pregnant or planning pregnancy
- Breastfeeding
- Diagnosed hypothyroidism
- Using non-iodized salt (Himalayan, sea salt)
- Vegetarian or vegan diet (no fish or dairy)
Example: pregnant woman in the US
- Life stage: pregnancy (US RDA: 220 mcg/day).
- Iodized salt (¼ tsp ≈ 1.5 g): ~45 mcg.
- 3 oz cooked cod: ~158 mcg (USDA FoodData Central).
- 1 cup low-fat milk: ~85 mcg (NIH ODS).
- Subtotal from food: ≈ 288 mcg → already above the RDA.
- Prenatal vitamin (ATA-recommended): +150 mcg.
How it works
1 min readWhat is Iodine
A mineral essential for thyroid hormone production and neurological health.
Daily Recommended Intake (RDA)
| Life Stage | mcg/day |
|---|---|
| Infant 0–6 months | 110 |
| Infant 7–12 months | 130 |
| Children 1–8 years | 90 |
| Children 9–13 years | 120 |
| Adolescents/Adults | 150 |
| Pregnancy | 220 |
| Breastfeeding | 290 |
Food Sources (mcg per 100g)
| Food | Iodine |
|---|---|
| Kelp seaweed | 2000–40000 ⚠️ |
| Cod | 170 |
| Iodized salt (1g) | 20–40 |
| Hake | 50 |
| Salmon | 40 |
| Dairy products | 40–80 |
| Egg | 25 |
| Yogurt | 30 |
Iodized Salt Standards
Many countries mandate iodized salt to prevent deficiency. For example, Argentina's Law 17,259 (1967) requires table salt to contain iodine (15–40 mg/kg). Switching to non-iodized varieties (Himalayan, sea salt) eliminates this important dietary source.
Iodine Deficiency Consequences
Excess Iodine
Common Mistakes
1. Using non-iodized salt (pink, sea salt) without supplementation
2. Vegans relying on seaweed without medical supervision
3. Consuming excessive seaweed
4. Pregnancy without prenatal supplementation
Related Calculators
Consult an endocrinologist if you have thyroid concerns.
Frequently asked questions
How much iodine do I need during pregnancy?
220 mcg/day according to WHO and NIH guidelines. For example, Argentina's Law 17,259 (1967) requires table salt to contain iodine (15–40 mg/kg).
Does pink Himalayan salt contain iodine?
No. Most non-iodized salts lack iodine, potentially causing deficiency.
Is seaweed a good iodine source?
Yes, in moderation. Kelp can be extremely high (2,000+ mcg/serving), so be cautious.
Do prenatal vitamins contain iodine?
Most do—typically around 150 mcg. Check your label to confirm.
Can too much iodine be harmful?
Yes. The upper limit is 1,100 mcg/day. Excess iodine can trigger thyroiditis.
How do vegans and vegetarians get enough iodine?
Use iodized salt, consume moderate seaweed (like nori), or take a 150 mcg supplement.
Can iodine deficiency affect my baby?
Yes. Severe deficiency during pregnancy can cause intellectual disability and cretinism.
What are the signs of iodine deficiency?
Goiter (enlarged thyroid), fatigue, weight gain, difficulty concentrating, and cognitive issues.