Seaweed & Iodine: What You Should Know

Seaweed is not only a sustainable and delicious ingredient — it’s also one of the richest natural sources of iodine, a mineral your body needs to produce thyroid hormones that regulate metabolism, energy, growth and development.

But the iodine content in seaweed varies widely by species, and getting the balance right matters for health.

Below, you’ll find an informative infographic that breaks down iodine levels across different seaweed types — and we’re grateful to New York Sea Grant for creating it:

Seafood-Seaweed-Infographic-Iodine.pdf

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Infographic credit: New York Sea Grant (source: nyseagrant.org/articles/r/23396).

Why Iodine Matters

Iodine is essential for healthy thyroid function. Both too little and too much iodine can affect your thyroid and overall wellbeing, so it helps to understand how much you’re getting from your diet — especially if seaweed is a regular part of it.

Swedish Iodine Recommendations

According to Livsmedelsverket, the following daily iodine intake levels are considered adequate for good health:

• Adults (18+): ~150 µg/day

• Children (1–10 yrs): ~100 µg/day

• Teens (11–17 yrs): ~120–140 µg/day

• Pregnant & breastfeeding women: ~200 µg/day

These values are based on the Nordic Nutrition Recommendations and reflect the amounts believed sufficient for normal thyroid function in the general population.

Seaweed Iodine: A Wide Range

Seaweed can be a powerful source of iodine — but the amount depends on the type:

• Brown seaweeds (e.g., kelp): Very high iodine content

• Red seaweeds (e.g., nori): Moderate levels

• Green seaweeds (e.g., sea lettuce): Lower levels

This variation means that a small serving of certain species can meet or exceed daily iodine needs, while others are more moderate.

Tips for Enjoying Seaweed Safely

• Know your species: Some kelp varieties are extremely high in iodine — check product info when possible.

• Balance intake: Pair seaweed with a varied diet to avoid excessive iodine exposure.

• Consider your needs: If you have a thyroid condition, pregnancy, or other health concerns, talk to your healthcare provider about what intake level is right for you.

Seaweed is a nutritious, sustainable ingredient with great potential in modern diets. Understanding its iodine content helps you enjoy it in a way that supports your health.