Do Mussels or Oysters Have More Iron? The Definitive Seafood Showdown

January 12, 2026 •

3 min read

According to the Dietary Guidelines for Americans, a standard portion of three oysters contains approximately 6.9 mg of iron, making it a powerful source of this vital mineral. But when comparing the two popular bivalves, do mussels or oysters have more iron overall? This guide offers a comprehensive look at their nutritional profiles.

Quick Summary

Oysters typically contain more iron per serving compared to mussels, but both are excellent sources of highly absorbable heme iron and other important nutrients.

Key Points

Iron Leader: Oysters typically contain more iron per serving than mussels.
Superior Bioavailability: Both oysters and mussels provide heme iron, which is easily absorbed by the body.
Zinc Powerhouse: Oysters are exceptionally rich in zinc, which is vital for immune health.
B12 Champion: Mussels are an excellent source of vitamin B12, supporting nerve function and red blood cell production.
Overall Nutrition: Despite differences, both shellfish are low in calories and rich in protein and omega-3 fatty acids.

Comparing the Iron Content: Mussels vs. Oysters

Iron is a critical mineral that plays a vital role in our bodies, primarily by producing hemoglobin, which carries oxygen in the blood. When it comes to finding great dietary sources, shellfish like mussels and oysters are often top contenders. While both are fantastic additions to a healthy diet, their iron content varies slightly.

Iron: A Head-to-Head Comparison

At first glance, the nutritional data shows a clear winner. Data from the Dietary Guidelines for Americans indicates that a serving of three oysters provides around 6.9 mg of iron. In comparison, a 3-ounce serving of mussels offers about 5.7 mg of iron. This means that, based on this standardized data, oysters generally have a higher iron concentration than mussels.

It's also important to consider the type of iron. Both oysters and mussels contain heme iron, which is the type of iron found in animal products. Heme iron is more easily and efficiently absorbed by the body than non-heme iron, which is found in plant-based sources. This high bioavailability makes both shellfish excellent choices for anyone looking to boost their iron intake, particularly those with or at risk of iron-deficiency anemia.

Beyond Iron: A Look at Other Key Nutrients

While iron is the focus, a full nutritional comparison reveals that both mussels and oysters offer a wide range of benefits. Here's how they stack up on other important micronutrients:

Zinc: Oysters are particularly renowned for their exceptionally high zinc content, a mineral crucial for immune function, metabolism, and healing. They contain significantly more zinc than mussels.
Vitamin B12: Mussels are noted for being a superior source of B-group vitamins, including B12, which is essential for nerve function and red blood cell production.
Omega-3 Fatty Acids: Both are excellent sources of healthy omega-3 fats, which support heart and brain health.

Factors Influencing Shellfish Nutrition

The exact nutrient composition of shellfish can be influenced by several factors, including the species, location, and cooking method. For instance, the iron content can vary between wild and farmed shellfish, and even between different species of oysters (e.g., wild Eastern vs. Pacific). Cooking methods can also play a role; some sources show cooked variations having slightly different iron levels compared to raw. For those concerned about iron overload, especially individuals with hemochromatosis, consulting a doctor is essential, as certain shellfish are very high in iron and should be consumed with caution.

How to Enjoy Mussels and Oysters

Incorporating both mussels and oysters into your diet can be a delicious and nutritious endeavor. Both can be steamed, fried, or added to various dishes. Here are a few ideas:

Oyster Dishes: Raw on the half-shell with a squeeze of lemon, grilled with a compound butter, or in a classic oyster stew.
Mussel Dishes: Steamed in a savory garlic and white wine sauce, added to a seafood pasta, or prepared in a spicy tomato broth.
Combo Platters: A seafood platter featuring both raw oysters and steamed mussels offers the best of both worlds.

Comparison Table


Nutrient (per 3 oz)	Oysters (Cooked Eastern)	Mussels (Cooked)
Iron	~7.83 mg	~5.7 mg
Zinc	Very High	High
Vitamin B12	High	Very High
Protein	Good Source	Good Source

Conclusion: Which Shellfish is Right for You?

When it comes to the question, "Do mussels or oysters have more iron?", the answer is that oysters hold a slight edge based on standard nutritional data. However, this is not the only factor to consider. Mussels offer a higher concentration of vitamin B12, while oysters are unparalleled for their zinc content. Both are excellent sources of bioavailable heme iron and provide valuable omega-3 fatty acids, making them highly nutritious additions to any diet. Ultimately, the best choice depends on your specific nutritional needs and taste preferences. For most people, including a variety of both shellfish in their diet is a fantastic way to enjoy a diverse range of nutrients. For comprehensive dietary information, refer to the Dietary Guidelines for Americans(https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/food-sources-select-nutrients/food-sources-iron).

Frequently Asked Questions

While both are excellent, oysters generally offer a slightly higher concentration of iron per serving than mussels. Some studies show that cooked Eastern oysters can contain nearly 8 mg per 3-ounce serving.

Yes, the iron found in shellfish like mussels and oysters is heme iron. This type of iron is absorbed much more efficiently by the body than the non-heme iron found in plant-based foods.

Oysters are a far superior source of zinc compared to mussels. In fact, oysters are one of the best dietary sources of zinc available.

Yes, but with precautions. According to the EPA and FDA, pregnant women should limit seafood consumption to 2 to 3 servings a week of 'Best Choices' seafood, which includes clams, oysters, and scallops, to minimize mercury exposure. Always ensure shellfish is fully cooked when pregnant to reduce the risk of bacterial contamination.

Cooking can cause some minor changes in nutrient levels, but it does not significantly degrade the overall nutritional profile. However, overcooking can affect texture and flavor. It's also important to note that specific iron counts can vary between raw and cooked forms.

Vegetarians and vegans can get sufficient iron by eating enough plant-based foods rich in non-heme iron, such as legumes, fortified cereals, spinach, and tofu. Pairing these foods with a source of vitamin C can also help improve absorption.

While mussels are a good source of iron, some varieties of clams can contain even higher amounts. Some sources indicate clams may have up to 24 mg per 3 oz, though iron content is highly variable by type.