Seafood is an essential part of many people’s diets around the world, and eating it has been associated with a variety of health benefits.

Seafood refers to several types of animals, including (1):

  • fish
  • crustaceans, like lobster and shrimp
  • mollusks, like clams and oysters
  • echinoderms, like sea urchins

This article explores the evidence-based health benefits of seafood and also covers some of the potential downsides to eating it.

There’s no doubt that seafood can positively influence health. Decades of scientific research have shown that diets high in seafood may help protect you from a variety of health conditions.

Plus, seafood is rich in nutrients that tend to be low in many people’s diets.

Here are some of the most impressive health benefits related to eating seafood, according to research.

Highly nutritious

Seafood is a concentrated source of many essential nutrients. Fish and shellfish, like salmon, clams, and shrimp, are particularly high in protein plus vitamins and minerals, like vitamin B12, selenium, and zinc.

For example, a 3-ounce (85-gram) serving of cooked clams provides (2):

  • over 3,500% of the Daily Value (DV) for vitamin B12
  • 99% of the DV for selenium
  • 21% of the DV for zinc
  • 13% of the DV for iron

A half fillet (154-gram) serving of wild-caught salmon delivers (3):

  • 196% of the DV for vitamin B12
  • 131% of the DV for selenium
  • 85% of the DV for vitamin B6
  • 21% of the DV for potassium

Studies show that many people don’t consume adequate amounts of certain nutrients that are concentrated in seafood, including vitamins B12 and B6, selenium, iron, and zinc (4, 5, 6, 7, 8, 9, 10).

This is concerning, as nutrient insufficiencies and deficiencies could negatively affect both physical and mental health and increase the risk of developing certain health conditions, including anemia, depression, and more (11, 12, 13, 14).

Therefore, eating seafood could cover common nutritional gaps, especially in people with diets low in nutrients and those who are more likely to have suboptimal intake or low blood levels of nutrients concentrated in seafood.

Young women, older adults, and people who are pregnant and breastfeeding may be especially at risk of having lower levels.

Primary source of omega-3 fatty acids

Seafood is the primary dietary source of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (15).

EPA and DHA are involved in many aspects of health, including nerve cell function and the regulation of inflammation (16, 17).

Research shows that diets high in seafood significantly benefit the health of the nervous and cardiovascular systems. Scientists think this is mainly due to the content of EPA and DHA in seafood.

For example, studies show that people who consume high amounts of omega-3-rich seafood tend to have lower rates of heart disease and cognitive decline (18, 19, 20, 21, 22, 23).

Linked to reduced disease risk

Because seafood is rich in nutrients, including protein, vitamins, minerals, and anti-inflammatory omega-3 fatty acids, it may offer protection against several health conditions.

A 2020 review that included 34 analyses of studies found that the higher people’s fish consumption, the lower their risk of coronary heart disease (CHD), heart attack, heart failure, stroke, depression, and liver cancer (23).

The review also showed that eating fish was associated with a lower risk of death from all causes.

Another 2020 review that included 40 studies demonstrated that higher fish consumption was significantly associated with a lower occurrence of CHD (18).

It also found that people who had a higher fish intake also had a significantly reduced risk of death from CHD.

Additionally, the study found that, as fish intake went up, CHD incidence and CHD-related death went down. Every 20 grams more of fish people ate per day was associated with a 4% decrease in CHD incidence and death from CHD.

This led the researchers to suggest people consume 60 grams of fish per day to reduce CHD and CHD-related death (18).

Summary

Seafood is highly nutritious, providing a source of healthy fats, protein, vitamins, and minerals. Eating seafood has been linked to a lower risk of many health conditions, including CHD, depression, and liver cancer.

Based on current evidence, seafood is a healthy dietary choice and provides important nutrients that may be lacking in many people’s diets.

Plus, research suggests that diets high in seafood may offer protection against health conditions like CHD and cognitive decline.

However, how and which types of seafood you consume seafood matter. Plus, there are some ethical and environmental concerns linked with seafood consumption.

Fried seafood may harm health

Frying any food, whether it’s chicken, potatoes, or fish, leads to unfavorable changes in the food, including the creation of harmful compounds.

Frying protein sources like fish creates compounds called heterocyclic amines (HCAs), acrolein, aldehydes, and polycyclic aromatic hydrocarbons. These are known to contribute to the development of diseases like cancer (24, 25, 26).

Studies have found that eating fried fish frequently is associated with an elevated risk of certain cancers, including lung and prostate cancer (25, 26).

Fried fish may have negative effects on heart health as well.

A 2019 study that included 106,966 postmenopausal women found that those who ate fried foods frequently, particularly fried chicken and fried fish, had a 13% increased risk of death from heart disease (27).

Intake of salted and smoked fish has also been associated with significantly increased disease risk.

A 2013 study in 2,268 men found that those who had a high intake of salted or smoked fish were two times more likely to be diagnosed with advanced prostate cancer both early or later in life (28).

Not only can these cooking methods increase your risk of disease, but frequently consuming fried or salted foods may contribute to other health issues, such as weight gain, high blood pressure, and more (29, 30).

Some seafood is high in mercury

Certain types of seafood are high in the heavy metal mercury (31).

Mercury levels in seafood depend on several factors, including the age and size of the fish and the water in which the fish lived (31).

Your body readily absorbs mercury, and it can cause health issues if too much accumulates in your tissues.

For example, being exposed to high mercury levels in the womb could lead to cognitive issues in children. High mercury levels may also increase the risk of high blood pressure and heart attack, and negatively affect your immune system (32).

Certain people, including children, pregnant and breastfeeding people, and those who frequently consume fish, are more at risk from eating seafood with high mercury levels (32).

Fish that are highest in mercury include:

  • shark
  • tuna, especially certain types
  • swordfish
  • tilefish
  • king mackerel

Tuna is considered the most relevant dietary source of mercury in the world. The body absorbs mercury more readily from raw tuna than cooked tuna, so if you eat raw tuna regularly, be aware of the risk of mercury accumulation (33).

Seafood that’s low in mercury tends to be smaller animals that are lower on the food chain, including (32):

  • trout
  • cod
  • haddock
  • herring
  • salmon
  • sardines
  • shellfish, like oysters and clams

Microplastic in seafood

Additionally, human activity has caused a buildup of microplastic in the marine environment. These are small pieces of plastic less than 0.19 inches (5 mm) in length that mostly come from human activities on land, like manufacturing and plastic waste (34).

Researchers warn that ingesting seafood containing microplastic likely harms health, though research in this area is limited (34).

Environmental and ethical issues

The demand for seafood has led to overfishing and has destroyed marine environments worldwide. Targeted species can’t reproduce quickly enough to replenish populations, which has led to a serious global issue (35).

Marine ecosystems are delicately balanced, and significantly reducing the number of one species can have catastrophic effects on others (36).

Commercial fishing vessels often use irresponsible methods of fishing, such as trawling, which not only destroys the delicate habitats on the ocean floor, but can lead to massive amounts of non-targeted species, like turtles and sharks, being caught as bycatch.

These fish and other marine animals have no use to commercial fishermen and are discarded overboard. According to some estimates, bycatch accounts for up to 40% of total global catch, which equates to 63 billion pounds per year (36).

Not only do overfishing and irresponsible fishing methods destroy marine ecosystems, but they also affect the nearly 3 billion people around the world who depend on seafood as a main food source (37).

Experts fear that the poor fishing management, irresponsible methods used to procure seafood, and the rampant overfishing that occurs worldwide will lead to a collapse of fisheries and a global food crisis (37).

Prioritizing sustainable fishing and fish farming practices is critical to protect existing marine environments.

You can help by reducing your overall consumption of seafood, purchasing only sustainably caught seafood, and avoiding eating species that are overfished.

You can start by using the Monterey Bay Aquarium Seafood Watch seafood recommendation search tool to find out about seafood that’s fished or farmed in environmentally sustainable ways.

If you’d like to reduce your intake of animal proteins, including seafood, try replacing them with plant-based proteins. Eating more plant foods can significantly reduce your environmental footprint and can promote overall health at the same time (38, 39).

Summary

Seafood can contain harmful contaminants, like mercury and microplastics, while eating fried seafood may increase the risk of certain health conditions. Plus, poor fishing management has led to overfishing and the destruction of marine environments.

There’s no doubt that seafood can be a good protein choice. However, it’s important to consider the health and environmental impacts of seafood if you want to incorporate it into your diet.

Here are a few tips on how to add seafood to your diet in a nutritious and sustainable way.

  • Choose fish that’s fished or farmed in environmentally sustainable ways. Clams as well as Arctic char from Canada caught by barriers and fences are among the best choices, and there are many more sustainable options.
  • Cook seafood in nutritious ways. Instead of breading and deep-frying or pan-frying seafood, try baking, sauteing, or steaming seafood.
  • Pair seafood with other nutritious foods. Use seafood in recipes with ingredients like vegetables, beans, and whole grains.
  • Eat more sustainable fatty fish. Some of the best choices for sustainably farmed or fished seafood happen to be loaded with omega-3 fatty acids. For example, pink and sockeye salmon and Atlantic and Pacific herring are high in omega-3s and are considered sustainable.
  • Avoid overfished species. Use the Monterey Bay Aquarium Seafood Watch online search tool to learn which fish are considered the worst choice for sustainability.
  • Watch out for high mercury fish. Avoid consuming high mercury fish, like tilefish, shark, king mackerel, marlin, swordfish, and bigeye tuna, whenever possible (40).
Summary

Use the tips above to add seafood to your diet in a nutritious and environmentally sustainable way.

Seafood is highly nutritious, which is why dietary patterns high in seafood have been linked to many benefits. For example, it may support heart health and protect against cognitive decline.

While seafood can be a healthy addition to your diet, it’s important to choose sustainably fished or farmed seafood, avoid high mercury fish, and limit your consumption of fried seafood whenever possible.