If you’re wondering about seafood nutrition, you’ve come to the right place! Seafood can be a healthy option for most people. This is your guide to the health benefits of fish and seafood, plus tips for eating more fish, more often.
Even before I became a registered dietitian, I was a huge fan of fish and seafood. The only problem is that I was born and raised in the Midwest, which is about as landlocked as you can be in the United States!
Now, whenever I’m recipe testing or traveling for work, I look for any excuse to enjoy some of my favorite fish and seafood dishes. And I’ve noticed it’s not always the most common or popular option, despite the many health benefits, great taste, and versatility. So I’m covering some of the most frequently asked questions about fish and seafood in this post.
Consider this your one-stop resource for all things seafood nutrition!
Seafood Nutrition FAQs Answered In This Post
What is “seafood”?
Think of it this way: all fish is seafood, but not all seafood is fish.
That’s because seafood is a much broader category than you might realize.
Yes, it includes both freshwater and saltwater fish, but also other types of seafood:
- Crustaceans, like shrimp, prawns, crab, and lobster
- Mollusks are a broad category of invertebrates with or without shells. Common species include:
- Cephalopods like squid and octopus
- Bivalves like clams, mussels, oysters and scallops
- Echinoderms like sea urchins
- Escargot, a type of land snail that is considered a delicacy
There are many other types of shellfish out there, but they are less commonly eaten or used as a food source.
Are seafood and shellfish the same thing?
Technically, anything harvested from freshwater lakes, streams, ponds, or rivers plus any saltwater species harvested from the ocean is seafood.
However, shellfish are biologically different than fish species with fins, vertebrae, and bones. This is important because some people are allergic to shellfish or choose to avoid them for religious reasons.
While these terms might have been used more interchangeably in the past, they usually refer to different things when featured on menus or in recipes to let people what they’re getting.
Seafood Nutrition
This next section will cover the basics of seafood nutrition, answering some of the most pressing questions I get as a dietitian.
Is seafood healthy?
In my opinion, yes, seafood is a healthy choice for most people. That’s because it’s a good source of protein, providing all nine essential amino acids we need from our diet.
When it comes to fat, there’s more info below. But be aware that not all fish is considered a lean protein. That’s because some types of fish are high in the types of unsaturated fats that are good for heart health, eye health, brain health and more.
But in addition to being a source of high-quality protein, fish and seafood can also provide these important nutrients:
- Vitamin B6 and vitamin B12
- Vitamin D (specifically salmon, which is one of the few foods that naturally has vitamin D)
- Iron
- Potassium
- Selenium
- Zinc, especially oysters and clams
The bottom line is that you can include a variety of fish in your diet. While everyone has different nutrition needs, you can rest easy knowing that fish and seafood provide many important vitamins and minerals for overall health.
What does the science say about Omega-3s?
It’s no secret that seafood packs a punch when it comes to nutrition. It’s included in the diets of some of the healthiest populations around the world. Many cultures have a long history of enjoying seafood in traditional diets.
Now let’s talk more about those unsaturated fats I mentioned.
There’s been a lot of attention (and research money!) directed towards omega-3 fatty acids for human health. In fact, omega-3s are one of the most studied nutrients of all. Here’s a quick rundown of what we know about the benefits of omega-3s:
- Heart Health: Enjoying seafood regularly can help lower blood pressure, decrease triglyceride levels, and increase consumption of omega-3 fatty acids.
- Brain Health: Seafood is a rich source of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). These fatty acids can be protective for brain health and cognitive function in adults. These essential fatty acids also support healthy brain development in infants and children. That’s why it’s recommended that pregnant women meet the recommended intake for seafood (two servings per week) to support a healthy pregnancy.
- Depression and Mood: There appears to be a link between high consumption of seafood and lower rates of depression in cultures that eat a lot of fish. Omega-3s may also help with depression and other mood disorders, but more research is needed and supplements should not be considered a primary treatment.
The best source of omega-3s fats is (surprise!) fatty fish, but fish oil supplements are also an option. Both the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) consider supplementation of up to 5 grams (5000 mg) per day to be safe.
You’ll likely see a lot of claims about omega-3s but keep in mind that we don’t always have all the answers. Nutrition science is always changing as new research comes out, so if you have questions or want to learn more, reach out to a dietitian or explore some of these resources:
I also did a deep dive on Omega-3, Omega-6, and Omega-9 fatty acids, which includes information about other sources beyond fish and seafood.
And always remember, just because I’m a dietitian doesn’t mean I’m your dietitian. Talk to your doctor and healthcare team before making changes to your diet or starting a new supplement. It should be personalized to you and what you need!
Which fish have the most omega-3s?
There is an acronym for this: SMASH. It stands for Salmon, Mackerel, Anchovies, Sardines, and Herring. Use this to easily remember which oily fish are highest in healthy fats.
When it comes to shellfish, oysters and mussels are also good choices.
But don’t feel like you should always try to choose fish that are on the higher end of the spectrum. We can also source omega-3s, EPA, DHA, and the precursor form, ALA (alpha linoleic acid) from other foods in our diet. This list includes nuts and seeds (especially walnuts), avocados, and supplements.
Can I get the same seafood nutrition benefits from fish if it’s fresh, frozen, or canned?
Fortunately, yes!
There is little or no nutritional difference between fresh, frozen, and canned seafood. We are lucky to have an abundance of options that can fit any budget.
Plus, for most of us here in the US, it’s not always practical or affordable to purchase fresh seafood. In fact, frozen or canned options are actually what I prefer because it’s often less expensive and better quality than some of the fresh options where I shop.
Learn more in this post: Is Canned Fish Healthy? Your Complete Guide to Nutrition, Taste, and Sustainability.
How To Eat More Fish and Seafood
If you’re sold on the idea of adding more fish and seafood to your diet, keep reading!
How much seafood should I be eating?
The current recommendation according to the Dietary Guidelines is two servings of fish per week. The American Heart Association agrees, recommending that as many servings come from fatty fish as possible.
A serving size is probably smaller than you think at just 3 ounces of seafood or cooked fish.
Can I eat seafood every day?
If you love fish and seafood and can’t get enough of it, go for it! Since they are such nourishing and health-promoting foods, rest easy knowing you’ll get many essential nutrients if you eat fish or seafood often.
There’s no major health concern with eating fish every day. However, you should consider cost and avoid species with high levels of mercury.
Which fish has high mercury?
It’s rare to see mercury toxicity from seafood consumption but it could happen if you were to only eat high-mercury fish. There’s good reason to avoid eating heavy metals, and being smart with seafood choices if another way to avoid the potential risk.
Here are four common species to be aware of:
- King Mackerel
- Shark
- Swordfish
- White or albacore tuna
These larger fish are exposed to mercury through environmental pollution. They’re also higher on the food chain, so mercury accumulates in their bodies when they eat smaller fish.
Street Smart Nutrition Tip: Choose light tuna as it is typically much lower in mercury than other types of tuna. Pregnant women should also avoid the type of tuna used for raw sushi (Big Eye Tuna) because, in addition to the potential risk of higher levels of mercury, it can be a food safety risk. Fish that’s been cooked to the recommended temperature of 145 degrees F is fine to eat.
Here’s some good news: most seafood and fish have very low amounts of mercury and are safe to eat often. Advisories are issued through state and local health departments and the EPA (U.S. Environmental Protection Agency) if there is concern for high mercury levels in local or domestic fish. The recommendation of two servings of seafood per week was set with mercury in mind. This level is not only safe, but encouraged!
Feel free to enjoy these options as often as you like:
- Trout (both lake trout and farm-raised rainbow trout)
- Whitefish like cod, haddock, and halibut
- Fatty fish like salmon, sardines, and herring
- Most types of shellfish
Who should not eat fish or seafood?
Although seafood can be part of a healthy diet for most people, certain people shouldn’t eat it.
- Strict vegans and vegetarians, although fish and seafood are included in pescetarian diets.
- Babies less than six months old. Fish and seafood is safe for young children, but should be introduced carefully along with other solid foods at the appropriate time.
- Anyone with a shellfish allergy should avoid that category of seafood. This goes for any other food allergy or sensitivity, too!
- Shellfish is not Kosher, so some Jewish people avoid it for that reason.
Even though the health benefits of fish and seafood are impressive, you can focus on getting them from other foods if they’re not an option for you.
And if you simply don’t like fish or seafood, that’s also fine! In my approach to gentle nutrition, there are plenty of ways to work around your taste preferences.
Is it OK to buy fish that isn’t wild-caught?
In my humble opinion, yes. Currently, it’s about a 50/50 split between farmed and wild-caught options in the United States. If you think about it, that might not seem like much, but consider that we usually don’t try to source half of our protein from wild sources for any other protein category. Aquaculture, or fish farming and cultivating plants and seafood to eat, helps ensure there’s enough seafood to meet demand.
Many people think farmed fish and seafood is inferior to wild-caught fish, but that’s not really the case.
It’s true that there are pros and cons to both options. You can read more about that in this post about salmon: Alaska vs. Atlantic Salmon: What’s the Best Salmon to Buy?
For example, wild-caught fish may use less sustainable fishing methods or result in bycatch, which can harm marine environments and other marine animals. Wild salmon might have higher levels of healthy omega-3 fats, but might also face health risks from pollution or microplastics.
There are many different ways to source seafood and fish. Not all of them are environmentally friendly, so I definitely recommend doing your homework to make sure your choices align with what you feel is most important. But not all farmed fish is bad and not all wild caught fish is good. I like to use Fish Watch and Seafood Watch (which also has an app!) to guide my choices when I’m shopping.
There you have it, answers to all your questions about seafood nutrition! Did I miss anything? Leave a comment below and let me know, or skip ahead to some delicious recipes like these:
- Furikake Salmon in the Oven or Air-Fryer
- Crunchy Cabbage Salad with Miso-Peanut Shrimp
- Daegu Jorim (Easy Korean Braised Cod)
- Homemade Cheesy Tuna Noodle Casserole
As always, thanks for stopping by the Street Smart Nutrition blog. Cheers to more fearlessly nourishing meals!
Disclosure: This post was originally published in October 2018 as part of a paid campaign with Seafood Nutrition Partnership. It has since been updated to improve the overall quality of the information and/or images. I did not receive additional compensation.
