Do Oysters Have More Iodine Than Shrimp?

January 13, 2026 •

4 min read

According to Healthdirect, a 90-gram serving of oysters can provide up to 144 micrograms of iodine, while a 100-gram serving of shrimp typically contains far less. This stark difference firmly answers the question: do oysters have more iodine than shrimp, and highlights oysters as a significantly richer source of this essential mineral.

Quick Summary

Oysters are a much more potent source of iodine than shrimp, largely due to differences in how they absorb the mineral from their marine environment. Both shellfish offer distinct nutritional benefits for a healthy diet.

Key Points

Iodine Concentration: Oysters contain significantly more iodine per serving than shrimp, making them a more powerful source of the mineral.
Nutritional Profile: While oysters are higher in iodine and zinc, shrimp offers higher protein and other nutrients like selenium and vitamin B12.
Source of Variation: The difference in iodine levels is influenced by the marine environment and how each organism feeds, with oysters being more efficient at absorbing it from seawater.
Thyroid Health: Adequate iodine intake is crucial for preventing thyroid issues such as goiter and hypothyroidism, which can cause fatigue, weight gain, and dry skin.
Dietary Balance: For a comprehensive nutrient intake, incorporating a variety of iodine-rich foods, including seafood, dairy, and iodized salt, is recommended.
Wild vs. Farmed: Wild seafood can sometimes have higher mineral content than farmed, but this varies; bivalves like oysters that filter-feed are less affected by farming practices.

The Iodine Showdown: Oysters vs. Shrimp

Iodine is a crucial trace element essential for the proper functioning of the thyroid gland, which in turn regulates metabolism, growth, and development. While many people associate seafood with high iodine content, not all ocean-dwelling creatures are created equal. The difference in iodine levels between oysters and shrimp is significant, with oysters holding a clear advantage as a denser source of the mineral.

Iodine Content: A Direct Comparison

The most straightforward way to settle the debate is by comparing the numbers. As cited by Healthdirect and the National Institutes of Health, the iodine content for a standard serving of each shellfish varies dramatically. This difference can be attributed to their distinct marine habitats and feeding methods. Oysters, being filter-feeders, absorb a high concentration of iodine directly from the seawater, while shrimp, which often inhabit coastal waters with lower concentrations, do not store the mineral as efficiently.

The Nutritional Power of Oysters

Beyond their superior iodine levels, oysters are nutritional powerhouses. They are particularly renowned for their exceptionally high zinc content, a mineral vital for immune function and cell growth. Oysters also contain significant amounts of iron, protein, and omega-3 fatty acids, making them a comprehensive addition to a healthy diet. The variation in iodine levels in wild vs. farmed oysters is generally smaller than in fish, as bivalves like oysters and mussels still feed by filtering water rather than relying on a formulated feed.

The Nutritional Value of Shrimp

While shrimp may not compete with oysters on iodine density, they remain a valuable and popular seafood choice. They provide a good source of protein, along with other key nutrients. These include selenium, a powerful antioxidant, and vitamin B12, important for nerve function and red blood cell production. They are also low in fat and calories, making them a healthy option for many diets. It is worth noting that wild-caught seafood, including shrimp, often contains higher mineral levels than their farmed counterparts, though this can vary depending on the specific feed used in aquaculture.

Comparison Table: Iodine and Other Nutrients (Per 90-100g Serving)


Nutrient	Oysters (Raw)	Shrimp (Cooked)
Iodine	~144 mcg	~13-35 mcg
Protein	~9g	~21g
Zinc	Very High	Present
Selenium	Good Source	Good Source

Note: Nutrient content can vary based on species, size, and source. For more information on the nutritional content of seafood, you can visit the NCBI website [https://www.ncbi.nlm.nih.gov/books/NBK605432/].

The Role of Iodine in Health

Iodine deficiency is a serious public health concern worldwide and can lead to a variety of health problems, particularly those affecting the thyroid. Adequate intake is essential for people of all ages, with recommended daily amounts increasing for pregnant and lactating women. Maintaining a balanced diet rich in natural iodine sources is a key strategy for prevention.

Here are some common symptoms of iodine deficiency, which can arise from an underactive thyroid (hypothyroidism):

Goiter: A visible swelling in the neck due to an enlarged thyroid gland.
Fatigue and Weakness: Persistent tiredness and a lack of energy.
Weight Gain: Unexplained weight gain can be a sign of a slowed metabolism.
Increased Cold Sensitivity: Feeling cold more easily than usual.
Dry Skin: Rough and flaky skin is a frequent symptom.
Hair Loss: Thinning hair or hair loss can occur with thyroid issues.

Other Dietary Sources of Iodine

While oysters are a concentrated source, they are not the only option for boosting your iodine intake. Many foods contain varying levels of this essential mineral.

Seaweed: Extremely high in iodine, with content varying by type.
Cod: A good source, providing a significant portion of the RDI per serving.
Dairy Products: Milk, yogurt, and cheese can be good sources, though iodine levels can fluctuate based on cow feed and disinfectants.
Eggs: The yolk, in particular, contains a good amount of iodine.
Iodized Salt: A fortified and widely available source of iodine, requiring only a small amount to meet daily needs.

Conclusion: Making the Right Choice for Your Diet

When comparing oysters and shrimp, oysters are the undisputed winner in terms of iodine concentration. However, a healthy and balanced diet should not rely on a single food source. While oysters provide a potent dose of iodine and an abundance of zinc, shrimp offers a leaner protein option rich in other valuable nutrients like selenium and B12. The best choice depends on your overall dietary goals and nutritional needs. Including a variety of seafood, along with other iodine-rich foods like dairy and iodized salt, is the most effective way to ensure adequate iodine intake and support optimal thyroid function.

Frequently Asked Questions

While it's difficult to get an excessive amount of iodine from food alone, especially for healthy individuals, consuming extremely high amounts from supplements or fortified foods can lead to thyroid problems. A balanced diet with varied sources is key.

Oysters are an exceptional source of zinc, which is vital for immune function and cellular health. They also provide significant amounts of iron, protein, and B vitamins.

Oysters are filter-feeders that absorb high levels of minerals directly from the concentrated iodine in seawater. Shrimp, especially those from coastal or farmed environments, don't accumulate the mineral as efficiently.

Cooking methods generally have a minor effect on iodine loss in fish and shellfish. However, processes that lead to high moisture loss, like drying, can increase the iodine concentration on a per-weight basis.

Studies show that wild seafood can sometimes contain higher iodine levels than farmed seafood, though this is not always consistent across all species. Bivalves like oysters, which filter-feed, are less affected by this difference.

An iodine deficiency can lead to a range of health issues due to an underactive thyroid (hypothyroidism), including a goiter (enlarged thyroid), fatigue, weight gain, constipation, and dry skin.

Other dietary sources of iodine include dairy products like milk and yogurt, eggs, and iodized table salt. Seaweed is a particularly potent, non-animal source.