What are the best (and worst) types of fish to eat for health?

Dietary recommendations have long included eating fish as part of a healthy diet, and for good reason. It’s a low-calorie, high-protein food, packed with many beneficial nutrients including omega-3 fatty acids. But not all fish and seafood are created equal. There are many risks for you to consider when choosing the best type of fish to eat.

Our bodies don’t produce omega-3 fatty acids, but they are essential for our health. The best way to get them is from the foods we eat, and fish is an excellent source of two types of omega-3s, DHA and EPA.

Eating fish also provides the body with protein, vitamin B2, vitamin D, iron, selenium, zinc, and iodine, according to the Food and Drug Administration (FDA).

One concern when choosing seafood, whether it’s fish or shellfish, is environmental contamination. The Environmental Protection Agency (EPA) have issued guidance around how to eat seafood safely to avoid consuming too many artificial chemicals that have traveled into water sources from our waste.

This guidance is particularly important for pregnant women and young children, who may be most impacted by high levels of contaminants.

There is also the issue of sustainability. “If the entire population were to follow the government guidelines, the oceans wouldn’t be able to sustain it,” notes Prof. Tim Spector, Professor of Genetic Epidemiology at King’s College London and Scientific Co-Founder of ZOE, in his book, Spoon-Fed.

With this in mind, we present our list of the best fish to eat for your health and the environment, and we also suggest a few to avoid. You may be surprised (salmon is not on our “best” list).

Best fish for health

Here are the top 7 best types of sustainable fish to eat for your health.

1. Farmed trout

As a lean white fish, rainbow trout is an excellent source of protein, yielding around 20.5 grams per 100 grams of fish. It is also high in calcium, potassium, and magnesium, and it is particularly rich in those valuable omega-3s.

Rainbow trout is a good species for farming, as the eggs are available year-round and are relatively inexpensive, compared with other fish in the salmon family.

Suppliers are also able to provide trout eggs that are certified free of pathogens. This means producers don’t need to use antibiotics or other chemicals, which are often found in farmed salmon and end up in our bodies when we eat them.

2. Oysters

An oyster is not a fish, but we’re including this mollusk in our list because — much like fish — oysters are high in omega-3s and are a good source of protein. Oysters are also a rich source of zinc, which supports the immune system.

One thing to keep in mind when eating deep-sea creatures that filter our water, such as mussels, clams, and oysters, is that any particles such as microplastics that they can’t break down are stored in their guts, which we then eat.

So, much like our advice with most sea creatures, eat these in moderation.

3. Sardines

Sardines are a type of small fish that eat plankton and small crustaceans. As a coldwater fatty fish, they are nutrient-rich and contain some of the highest omega-3 levels while also retaining very low levels of mercury.

They are naturally high in vitamin D and calcium, and they are quick to reproduce, making them a particularly sustainable choice. Combine them with pasta for a quick and tasty meal. 

4. Anchovies

A great addition to pizza, anchovies are a small saltwater fish that are caught in the wild and are highly sustainable. Like sardines, anchovies are high in omega-3s and low in mercury, and they are a good source of selenium and folate.

The great thing about anchovies is that they are available fresh, canned, salted, oiled, or as a paste, making them highly versatile. Here are some anchovy recipes to get you started.

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5. Herring

Herring are silver in color and can be found in both fresh and saltwater. This sustainable fish is a staple food in many cultures and can be eaten in many different ways, including raw, dried, and fermented. Herring have also been salted in Europe for at least 1,000 years.

This fish packs a health punch, surpassing both sardines and trout in terms of omega-3 content.

6. Wild Alaskan pollock

Wild Alaskan pollock is also called walleye pollock. A member of the cod family, it is similar in flavor and texture, and boasts a whopping 23.5 grams of protein per 100 grams.

Alaskan pollock grow quickly and have a relatively short lifespan of around 12 years. This means they are more productive compared with slow-growing, longer-living species, making them a top sustainable choice for your health.

7. Mussels

Another mollusk that has snuck into our list is the mussel. Mussels are an affordable, sustainably produced species rich in omega-3s.

You may be surprised to know that a serving of mussels provides twice as much iron as a steak. There are 6.72 milligrams of iron in 100 grams of mussels, compared with 3.47 milligrams in 100 grams of steak.

Like oysters, however, you’ll want to eat them in moderation, as they also filter our water and are at higher risk of containing microplastics and other contaminants.

Fish to avoid

There are aspects of the fishing industry that seem like fishy business. As a consumer, it’s important to be aware of what you’re putting in your body.

At ZOE, we run the world's largest study of nutrition, and we know that each individual's responses to food are completely unique to them. You can take a free quiz to learn more about how your food responses contribute to your overall health.

And here are some reasons why you may want to avoid certain species of fish.

Antibiotics

Many species of farmed fish, particularly salmon, require routinely high levels of antibiotics to avoid infections.

Worryingly, a 2017 study revealed that fishmeal products from around the world have not only high levels of antibiotics, but also hundreds of antibiotic resistance genes, which can then transfer to humans who eat them.

For this reason, farmed salmon is a type of fish you'll want to be wary of.

Fish fraud

Fish fraud is also something to put on your radar. Have you ever ordered white tuna at a sushi restaurant? There is no such fish. In many cases, this is escolar, a cheap fish that is linked with stomach distress and is referred to as the “ex-lax fish” in the industry.

But even upscale restaurants may not be safe. A 2019 report conducted by ocean conservation group Oceana found that, of the 400 seafood samples they collected from over 250 locations in the U.S., 21% were mislabeled.

And 1 in 3 establishments sold at least one item of mislabeled seafood, with restaurants and smaller markets more frequently mislabeling seafood, compared with the larger chain grocery stores.

Chemicals

Another major cause for concern when eating seafood is the contamination factor.

Chemicals such as cadmium, lead, or mercury have entered our water and contaminated some species. Those that have the highest risk are bigger, longer-living species, including yellowfin tuna, shark, marlin, halibut, and swordfish.

Pregnant women and young children in particular will want to steer clear of these fish types because they can be bad for their health. 

Takeaway

Fish and shellfish are excellent sources of omega-3 fatty acids, protein, and other beneficial vitamins and nutrients. However, not all fish are created equal.

It’s important to be aware of issues like environmental contamination, which can pose risks for us all, but particularly for pregnant women and children.

In his book Spoon-Fed, Prof. Spector provides some excellent tips to bear in mind when choosing seafood:

• Consider fish and shellfish to be a treat rather than an everyday food and pay a bit more for better quality if you can.

• Work to understand the source of your seafood. Is it farmed? Is it wild? And what does it mean for that species?

• In general, the closer the seafood is to the original source of nutrients, the better it is for our health. For example, small fish that eat plankton, including sardines and herring, are healthier for us than eating the larger fish that feed off them, including salmon and mackerel.

• Try to vary species and choose fish that are sustainable, high in nutrients, and low in chemicals such as mercury.

If you want to learn more about how your body uniquely responds to food, check out ZOE, the health science company co-founded by Prof. Spector.

ZOE uses data from the largest in-depth nutrition study in the world and cutting-edge tests to analyze your gut microbiome, as well as your blood sugar and fat responses, to help you pick the best foods for your health.