Seafood is a broad food category that covers a wide range of different foods.
These foods come under distinct groups like finfish (such as cod), crustacean shellfish (shrimp), mollusk shellfish (oysters), and sea vegetables (seaweed).
Seafood can have a wealth of nutritional benefits, ranging from omega-3 in oily fish to exceptional nutrient-density in foods like oysters and clams.
This article examines the most common types of seafood and their nutritional properties. For each one, we’ll let you know its calorie, omega-3, and protein content, as well as its key (top three highest) vitamins and minerals.
Source and methodology note: Unless otherwise stated, nutritional data in this article is for cooked weight and is sourced from the USDA’s FoodData Central database. Percent daily values (% DV) have been calculated based on the FDA’s current daily values, which are based on a 2000-calorie diet.
Anchovies share some common traits with sardines; they’re both small types of oily fish. However, anchovies have a noticably stronger flavor.
This is due to their high glutamic acid content, which is the same amino acid that is part of MSG (monosodium glutamate). Many fish sauce products, which are used for flavoring many Asian dishes, are based around anchovies due to their flavor.
While also available fresh, anchovies are among the most common canned fish products.
Eel has an unusual long body and slightly resembles a snake in its appearance, but it’s a variety of fish.
This fish has been a traditional food in much of Europe and the United States, although it isn’t as commonly consumed as in the past. Eel features in East Asian cuisine typically marinated and grilled and as sushi in Japan.
Fish roe refers to the eggs of finfish. While not commonly consumed in the Western world, it is extremely popular in Japan and Eastern Russia.
Fish roe is very nutrient-rich, providing an impressive range of nutrients in high concentrations. These include high amounts of omega-3, vitamin D, significant amounts of protein, and more.
There are many different varieties of fish roe, so nutrient content will vary slightly by type. However, the nutrients below represent the average data from ‘mixed species’ provided by the USDA.
Herring is a small and nutritious oily fish with a relatively strong flavor and soft texture.
It has an interesting history as a traditional breakfast food, particularly in the UK and some areas of North America. Also known as ‘kippers’, this traditional food involves eating whole herring in their “kippered” (salted and smoked) form.
Like other oily fish, herring provides a considerable amount of omega-3 and high levels of numerous vitamins and minerals.
However, there are several different species of mackerel, and not all of them are equal when it comes to mercury content, a heavy metal that can negatively impact health when overconsumed.
For example, research shows that Atlantic mackerel contains very low levels of mercury whereas King mackerel contains high amounts.
One of the best things about mackerel is its affordability, typically selling for about half the price of salmon, with canned and frozen mackerel being even more budget-friendly.
Salmon is a versatile food that can be eaten fresh, as raw fish (sashimi), smoked, or in canned form.
Nutritionally, salmon is among the best sources of omega-3 and it contains astaxanthin, a carotenoid that may help improve UV resistance and reduce signs of skin aging.
Sardines are among the most affordable and nutrient-rich fish.
Canned sardines are one of the best budget-friendly choices, and they are full of omega-3 fatty acids.
Since we eat sardines in their whole form, including the small bones they contain, they offer exceptional nutrient density and a good non-dairy source of calcium.
Like basa, swai is a lean white fish that has become popular globally due to its affordable price point.
As two closely related species, basa and swai are often confused as the same fish. However, they are two distinct species.
Swai provides a low-calorie, concentrated source of vitamins and minerals.
Key Nutrients Per 100g:
Calories: 98 kcal
Omega-3: 0.03 g
Protein: 17.8 g
Selenium: 27% DV
Source: Due to a lack of reliable nutritional data from the USDA, these values for swai fish were obtained from an analytical study on the nutritional composition of swai fish. Unfortunately, incomplete data was available for its full vitamin and mineral profile.
Some types of trout, such as rainbow trout, are sometimes mistaken for salmon due to their similar appearance. While they are distinctly different fish, both trout and salmon belong to the wider Salmonidae family of fish.
Both fresh and canned tuna are a popular part of diet globally.
However, there are numerous different varieties of tuna, each with a unique nutritional composition.
Some of these varieties can be high in protein and low in fat, such as typical canned Skipjack tuna. In contrast, other types of tuna, such as fresh Bluefin, contain a bit more fat and comparatively less protein.
Crab tastes somewhat similar to white fish, with a mild and slightly sweet flavor.
However, it belongs to the same crustacean shellfish category of seafood as shrimp. It is estimated that approximately 0.4–2.5% of the global population has an allergy to crustacean shellfish globally.
Crab is typically bought fresh, but it is also available in canned form.
Also known as crayfish, crawfish are a crustacean shellfish that slightly resemble a small lobster in appearance and taste.
Crawfish are nutrient-rich, popular for culinary use, and feature in many soups. As they are so small, they absorb flavors from other ingredients in dishes.
Lobster is a popular, but typically quite expensive, crustacean variety of shellfish. While it is nutrient-rich, most people who enjoy lobster make it an occasional thing due to its high price tag.
Lobster is high in protein and offers a wide range of vitamins and minerals for very few calories.
Note: Please note that the USDA data is for fried abalone, meaning the total calories is influenced by the oil used for frying. Other cooking methods, such as steaming, would result in a significantly lower calorie count.
Clams are a type of mollusk shellfish that offer exceptional nutritional value. Like other mollusks, such as oysters, they have a salty taste and a soft, chewy texture.
Clams are protein-dense and among the nutrients they contain, they offer a significant amount of vitamin B12.
Note: The omega-3 content and full vitamin and mineral profile of cockles was unavailable in the USDA data. To provide this information, the omega-3 and micronutrient data was sourced from the NCC Food and Nutrient database, accessed through Cronometer.
Alongside octopus and squid, cuttlefish is a cephalopod – technically classed as a mollusk shellfish.
Cuttlefish is a popular part of the diet in some regions of Europe, the Mediterranean, and East Asia. It is available fresh, frozen, and even in a dried snack “jerky” form.
Cuttlefish contains very high levels of protein and a range of essential nutrients.
Mussels are another nutrient-rich mollusk shellfish, providing a substantial source of B vitamins and manganese.
They are both mild and salty, with a soft and chewy texture. Like other mollusks, they are typically eaten with seasonings such as lemon, soy sauce, and garlic.
Although octopus is not commonly consumed in many Western countries, it is a valued part of the cuisine in countries such as Japan, Korea, Singapore, Italy, and Spain.
It is classed as a type of mollusk and has an impressive nutrient profile, containing particularly high levels of vitamin B12 and selenium.
Oysters are arguably the most commonly consumed type of mollusk, and they are extremely nutrient-dense. They contain similarly high levels of vitamins and minerals to foods like liver.
Scallops are a mollusk shellfish that share some common properties with clams.
However, the only part of a scallop typically consumed is the large adductor muscle – this is the muscle responsible for closing its shell. This muscle is very large, and bigger than clams (which are consumed whole).
Since clams are eaten whole, this includes all their organs and this makes them a highly concentrated source of vitamins and minerals. Despite this, scallops still contain a good amount of many essential vitamins and minerals.
Squid is otherwise known as calamari in culinary terms, and it is a popular food in cuisines worldwide. It is a type of mollusk shellfish.
Depending on the country, it can be prepared in various ways. For example, in the Mediterranean region, it is frequently fried or incorporated into stews. In contrast, people may eat it raw in East Asia as sashimi or sushi.
Whelk is another gastropod (sea snail) type of mollusk shellfish.
Like conch and mollusks in general, whelk provides significant concentrations of vitamins and minerals, particularly vitamin B12 and selenium.
Key Nutrients Per 100g:
Calories: 137 kcal
Omega-3: 0.01 g
Protein: 23.8 g
Vitamin B12: 378% DV
Copper: 120% DV
Selenium: 81% DV
Source note: Unlike for most other seafood options in this guide, we used ‘raw’ USDA data for whelk. This is because there appears to be serious errors with the USDA’s data for cooked whelk, with unlikely values being present, such as 48g of protein per 100g.
In addition to fish and shellfish, there’s an often forgotten category of seafood that can be incredibly nutritious: sea vegetables.
However, consumption of foods like seaweed varies heavily depending on location and local cuisine. While seaweed is a common staple in some countries, it is barely consumed in others.
Notably, some types of seaweed offer exceptionally high levels of iodine – some of these are even to levels where excessive intake is possible.
There are numerous varieties of seaweed, with kombu, nori, and wakame being some of the most common.
To resolve any potential queries, here are the answers to some common questions about seafood.
Which is the best seafood?
There is no “best” seafood; many seafood options offer good nutritional value, so taste preferences and affordability are key considerations. However, oily fish offer something (omega-3) that not all seafood provides. In the same way, shellfish tend to contain higher levels of vitamins and minerals than regular fish.
Is eating seafood expensive?
Seafood can be very expensive, but it can also be relatively affordable. Some of the most budget-friendly seafood options include tinned sardines and mackerel. Aside from this, frozen fish offers more value per gram than fresh seafood. Canned fish have all the same beneficial nutrients as fresh fish, making them a comparatively budget-friendly source of omega-3, protein, and more.
Can you get sick from eating seafood?
Like with most foods, it is possible to get sick from seafood. Unfortunately, some people have allergies to shellfish and finfish. Additionally, storing and handling seafood correctly is essential. For frozen and fresh seafood products, it is important to follow the storage and preparation instructions and not to leave them at room temperature. Anyone with specific health concerns about seafood should consult their healthcare provider.
What are the best seafood choices for omega-3?
Oily fish is the best choice for omega-3 content. Some commonly consumed oily fish include salmon and mackerel. See this list of oily fish with high omega-3 content for more information.
Which common seafood contains the most mercury?
Tuna is probably the most common seafood option with moderate to high mercury levels. The FDA offers useful advice on the best and worst fish options based on their mercury content.
See this comprehensive guide to seafood with the highest and lowest mercury levels for more information:
It can be, but it depends on the specific variety. Generally speaking, lean white fish (such as cod and haddock) tend to provide the most protein per gram. For more information, see this list of fish and shellfish with the highest protein content.
Final Thoughts
As shown throughout the nutrition profiles of these foods, seafood is much more than just omega-3.
Fish, shellfish, and sea vegetables are some of the most nutrient-rich choices out of any food group.
Depending on what you’re looking for, there are a wide range of choices for prioritizing protein (lean white fish), omega-3 (oily fish), or nutrient density (mollusk shellfish).
While some forms of seafood can be very expensive, many nutrient-rich options are reasonably priced, offering an affordable way to improve our overall diet. Both canned and frozen seafood are typically the most budget-friendly options, and they are still rich sources of nutrients.
Michael works as a nutritionist in a community setting and holds a Master's degree in Clinical Nutrition. He is a Registered Associate Nutritionist (ANutr) with the Association for Nutrition (AfN), and has published peer-reviewed research.
