What Seafood Has the Most Vitamins? A Nutritional Deep Dive

November 25, 2025 •

4 min read

According to the NHS, a healthy diet should include at least two portions of fish per week, with one being oily fish, to provide valuable vitamins and minerals. But many wonder what seafood has the most vitamins, and the answer is often found in small, fatty fish and certain shellfish.

Quick Summary

Seafood offers a rich source of vitamins, with fatty fish like sardines, mackerel, and wild salmon providing high levels of Vitamin D and B12. Shellfish, including clams, oysters, and mussels, are also vitamin B12 powerhouses and are packed with beneficial minerals. To maximize benefits, choose low-mercury, sustainable options and opt for healthy cooking methods.

Key Points

Oily fish are vitamin powerhouses: Small, fatty fish like sardines, mackerel, and salmon are exceptionally rich in Vitamins D and B12, essential for immunity and energy.
Shellfish lead in B12: Clams, mussels, and oysters offer exceptionally high concentrations of Vitamin B12, with clams providing thousands of times the daily value in a single serving.
Vitamin D from seafood: Fatty fish such as wild salmon and trout are among the few natural dietary sources of Vitamin D, a nutrient vital for bone health.
Mercury levels matter: Smaller, younger fish and shellfish tend to have lower mercury levels compared to larger predatory species like shark and swordfish.
Cooking methods are crucial: To retain maximum nutritional value and avoid harmful compounds, healthy cooking methods like baking, steaming, or grilling are recommended over frying.
Sustainability is key: Opt for sustainably sourced seafood certified by organizations like the Marine Stewardship Council to support healthy ecosystems.

Unlocking the Nutritional Power of Oily Fish

Oily fish are generally the champions when it comes to vitamin content, particularly fat-soluble vitamins like D and A. The oils in these fish also contain crucial omega-3 fatty acids, which work alongside vitamins to support brain and heart health. Incorporating a variety of these fish into your diet is an excellent way to boost your vitamin intake.

The Top Contenders

Several species consistently top the charts for their vitamin density:

Sardines: These small, oily fish are eaten whole, meaning you get the benefits of the flesh, skin, and bones. A single serving can provide over 100% of your daily needs for Vitamin D and B12.
Mackerel: Similar to sardines, mackerel is rich in healthy fats, protein, and B vitamins, including B12. It's also a great source of selenium, which supports a healthy immune system and thyroid function.
Wild-Caught Salmon: Wild salmon is a nutritional heavyweight, high in protein, antioxidants, and a wide array of B vitamins. It is also one of the few natural food sources high in Vitamin D.
Trout: Closely related to salmon, trout is an excellent source of food-based Vitamin D and B12. It is a versatile, mild-flavored fish that is easy to prepare.

The Mineral-Rich World of Shellfish

While fish like salmon are renowned for their B and D vitamins, shellfish hold their own, particularly for their extremely high concentration of Vitamin B12 and key minerals.

Shellfish Vitamin Kings

Clams: These small bivalves are arguably the top source of Vitamin B12 in any food, with some varieties offering thousands of times the Daily Value in a single serving.
Oysters: Oysters are not only rich in Vitamin B12 but also an exceptional source of zinc, which is crucial for immune function and wound healing.
Mussels: A great source of lean protein, mussels provide high amounts of Vitamin B12 and manganese, a trace mineral important for bone health.

Comparing Vitamin Content: Fish vs. Shellfish


Seafood Type	Primary Vitamins	Key Minerals	Mercury Level	Best for	Notes
Sardines	Vitamin D, B12, B3 (Niacin)	Selenium, Calcium (in canned)	Low	Vitamin D and B12 boost, heart health	Eating whole boosts calcium intake.
Wild Salmon	Vitamin D, B12, B6	Selenium, Potassium	Low	Overall nutritional profile, brain health	Rich in omega-3s.
Clams	Vitamin B12 (Exceptionally high)	Iron, Zinc, Selenium	Low	B12 boost, iron intake	Nutrient density is outstanding.
Mackerel	Vitamin D, B12, B3 (Niacin)	Selenium, Protein	Low (smaller varieties)	Omega-3 intake, high nutrient density	Excellent source of selenium.
Oysters	Vitamin B12	Zinc (Very high), Copper	Low	Immune support, high zinc intake	Best consumed steamed or baked.

Cooking Methods and Sustainability

The way you prepare seafood significantly impacts its final nutritional value. Steaming, baking, or grilling seafood are healthier choices than frying, which adds unhealthy fats and calories. Frying can also create harmful compounds that increase health risks. Furthermore, choosing sustainable seafood is a key consideration for both environmental health and your own. Large, older predatory fish like shark and swordfish contain higher levels of mercury, which is a neurotoxin, while smaller, younger fish tend to have much lower levels. Look for certifications from organizations like the Marine Stewardship Council (MSC) to ensure your seafood is responsibly sourced.

Choosing the Right Seafood for Your Needs

For a powerful dose of fat-soluble Vitamin D, essential for bone health and immune function, reach for fatty fish like wild salmon, sardines, and trout. If you're seeking to maximize your intake of Vitamin B12, crucial for red blood cell formation and neurological function, shellfish like clams and oysters are unparalleled. Regardless of your specific needs, incorporating a variety of low-mercury, sustainably sourced seafood into your diet is the best approach for a comprehensive nutrient profile.

The Importance of Overall Dietary Balance

While seafood is incredibly nutritious, it should be part of a balanced diet that includes a wide array of fruits, vegetables, whole grains, and lean proteins. This ensures you receive a full spectrum of vitamins, minerals, and other beneficial compounds necessary for optimal health. Consuming a diverse diet not only boosts overall nutrition but can also help mitigate potential risks associated with consuming any single food type too frequently. The American Heart Association recommends two servings of fish per week for better heart health.

Conclusion

When asking "what seafood has the most vitamins?", the answer points toward a combination of oily fish and specific shellfish. For Vitamin D and omega-3s, oily fish such as salmon and sardines are your best bet. For a remarkable source of Vitamin B12, shellfish like clams and oysters are in a class of their own. By choosing a variety of low-mercury, sustainable options and using healthy cooking methods, you can maximize the vitamin and mineral benefits that seafood provides for a healthier diet.

Outbound Link

For more detailed information on making sustainable seafood choices, refer to the Monterey Bay Aquarium's Seafood Watch guide: Seafood Watch

Frequently Asked Questions

Clams contain the highest concentration of Vitamin B12 among all seafood, with cooked clams providing thousands of times the Daily Value in a 3-ounce serving.

Yes, wild-caught salmon is an excellent source of several vitamins, including Vitamin D and a wide array of B vitamins like B12 and B6.

Fatty fish, such as wild-caught salmon, trout, and sardines, are among the best dietary sources of Vitamin D.

Some seafood, especially large predatory fish, can accumulate higher levels of mercury. It's best to choose smaller, low-mercury species and eat a variety of seafood to minimize risks.

Healthy cooking methods like steaming, baking, or grilling are best for retaining nutrients. Avoid deep-frying, which can add unhealthy fats and reduce the nutritional benefits.

Yes, canned sardines are highly nutritious. Because they are often eaten whole, including the softened bones, they provide extra calcium that fresh sardines often lack.

Oysters and mussels are rich in Vitamin B12, zinc, and selenium. These nutrients support immune function, nerve health, and overall metabolism.