Top Fish for High Iodine Content
When considering which fish has the highest iodine, it's important to look at several factors, including the type of fish and how it is prepared. While anchovies may have the highest iodine content when measured raw in certain studies, other lean, wild marine fish like haddock, pollock, and cod are also excellent sources and more commonly consumed. The mineral is primarily absorbed from seawater, so marine species naturally contain higher levels than freshwater fish.
Anchovy: A Potent Iodine Source
Recent research has brought new attention to the anchovy as a standout source of iodine. A 2024 study on fish from the eastern Black Sea region showed raw anchovies possessed the highest iodine content of the tested species, at 295.9 micrograms per 100 grams (dried weight). Marinated anchovies also demonstrated a significant concentration increase due to water loss and salt content during processing. This high concentration makes anchovies, often sold dried or marinated, a powerful way to add a concentrated dose of iodine to your diet, even in small portions.
Haddock: Another Iodine Powerhouse
In contrast to the tiny anchovy, the larger, lean white fish known as haddock is also remarkably high in iodine. A study focusing on Norwegian fish revealed that haddock had an average iodine content of 400 mcg per 100g, with some samples containing significantly more. A key finding showed that oven-baking could concentrate the iodine content, making a 150g serving of oven-baked haddock one of the most efficient ways to meet the daily recommended intake. This makes haddock a versatile and nutritious option for those looking to boost their iodine levels.
Other Excellent Fish Options
Several other fish species contribute significantly to iodine intake, offering variety for your meal planning:
- Cod: A 3-ounce (85g) serving of cooked cod can provide up to 158 mcg of iodine, meeting or exceeding the daily recommended intake for most adults.
- Pollock: As part of the cod family, pollock is another lean white fish with high iodine levels. A Norwegian study found pollack contained an average of 790 mcg per 100g.
- Saithe: Also known as coley, saithe is a lesser-known but robust source, with Norwegian studies reporting mean values of 280 mcg per 100g.
- Other Marine Fish: Species like sea bass, perch, and marine fish in general contain notable amounts of iodine, making regular seafood consumption a smart strategy.
Comparison Table: Iodine Content in Common Fish
It is important to remember that iodine content can vary widely within a species due to environmental factors, seasonality, and cooking methods.
| Fish Species | Average Iodine Content (per 100g, wet weight) | Key Insight |
|---|---|---|
| Anchovy | ~176–296 µg (raw) | Highest raw levels, but processing may alter significantly. |
| Haddock | ~400 µg | Very high, especially when baked, which concentrates the nutrient. |
| Pollock | ~790 µg (wild) | One of the highest levels, showing significant variance based on location. |
| Atlantic Cod | ~190 µg | Excellent and reliable source, though content depends on water source. |
| Atlantic Halibut | ~21 µg | Much lower content than lean fish due to higher fat content. |
| Saithe | ~280 µg | A substantial source, influenced by factors like season and catch area. |
The Impact of Cooking on Iodine Content
Cooking methods play a critical role in determining the final iodine content of your fish. Studies have shown that boiling can lead to a significant loss of water-soluble iodine, with some research indicating a 10-20% reduction in cod fillets. In contrast, cooking methods like pan-frying and oven-baking can increase the iodine concentration per 100g by reducing the fish's moisture content. Therefore, for maximum iodine retention, it is best to bake, grill, or fry your fish rather than boiling it.
Incorporating High-Iodine Fish into Your Diet
Including high-iodine fish in your regular diet is a straightforward way to support thyroid health. A simple plan might involve alternating between cod, haddock, and anchovies throughout the week. For example, a baked haddock fillet for dinner, a salad topped with marinated anchovies for lunch, or cod in a stew (where the cooking water is consumed) can all contribute meaningfully to your intake. As with any dietary change, moderation and variety are key to balancing all nutritional needs. For specific health concerns, it is always best to consult a healthcare provider.
Conclusion
While seaweed often takes the top spot for overall iodine concentration, several species of marine fish are excellent and more accessible sources for most Western diets. Anchovies, haddock, and pollock stand out for their particularly high iodine content. To maximize intake, opt for lean marine species and prepare them by baking or pan-frying to minimize nutrient loss. By understanding which fish has the highest iodine and how to best prepare it, you can easily support your thyroid and overall well-being. For a comprehensive overview of nutritional requirements, including iodine, refer to authoritative health resources like the National Institutes of Health.
