3 of the Healthiest (and Worst) Fish, According to Our Dietitians

Bored with salmon? Get tips on expanding your protein options

It’s time for dinner and you’re hankering for healthy protein. Fish sounds good, but you don’t want salmon — again. Our dietitians suggest expanding your horizons with three underappreciated fish that deserve more attention:

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1. Sardines

“You can’t go wrong with sardines. They’re a wonderful source of omega-3 fatty acids, they’re caught in the wild, and they’re cheap,” says Kristin Kirkpatrick, MS, RD, LD.

Sardines provide 2 grams of heart-healthy omega-3s per three-ounce serving, “one of the highest levels of omega-3s and the lowest levels of mercury of any fish,” notes Brigid Titgemeier, MS, RDN, LD.

“And because sardines are more likely to be sustainably caught, they’re a safe choice for pregnant and nursing women.”

Sardines are also a great source of calcium and vitamin D, so they support bone health too. “Other than fortified products, there are few other food sources of Vitamin D,” notes April Verdi, RD, LD.

Sardines may be packed in water, tomato juice or olive oil. Read the label to make sure you don’t exceed your daily limits for sodium and fat.

Worried about encountering the entire fish, head intact? “Today, only the edible portions are included,” says Ms. Verdi. “Try serving sardines sprinkled with lemon juice and 1 teaspoon of olive oil, or with chopped tomatoes and basil, oregano or another Italian seasoning.”

2. Herring

“This little fish boasts more omega-3 fatty acids than either salmon or tuna,” says Anna Taylor, MS, RD, LD, CDE. “Our bodies can’t make these fats, which are essential to human health.”

Fatty fish like herring provide around 1.5 grams of omega-3s per three-ounce serving.

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Herring also contains less mercury than other omega-3-rich fish you may be eating, like tuna, king mackerel, swordfish and halibut.

Not sure how to serve herring? “Try it chilled, with a light marinade of white wine vinegar, red onion and dill,” says Ms. Taylor. “Another popular option is to pair herring with mustard and dill.”

 3. Mackerel

“Atlantic and Atka mackerel from Alaska are high in inflammation-fighting omega-3s and low in mercury,” says Julia Zumpano, RD, LD.

But not all mackerel get a thumbs-up. King mackerel, from the Western Atlantic and Gulf of Mexico, has a high mercury content. She suggests limiting Spanish mackerel as well due to mercury concerns.

“Try grilling or poaching mackerel to throw over a salad, or serve it with a side of grilled veggies,” she suggests. 

Fish you should reconsider

Meanwhile, think twice about ordering these popular fish or adding them to your grocery cart:

1. Tilapia

“Sure, tilapia is a lean source of protein, but it lacks the omega-3 content of fatty fish like salmon, tuna, herring and sardines,” says Ms. Taylor.

Ms. Verdi agrees. “Most people don’t get enough omega-3s in their diet. So if you’re going to enjoy fish, it’s best to choose fish that are highest in this essential nutrient.”

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2. Tuna

“Fresh tuna are a great source of omega-3s. But everyone’s desire for sushi may be putting us at risk for mercury toxicity,” cautions Ms. Kirkpatrick.

Exposure to high levels of mercury increases the risk of cognitive defects and other health problems.

And you’re not necessarily safer with canned tuna. “Albacore tuna, one of the more popular fish in the United States, is consistently high in methylmercury,” notes Ms. Titgemeier.

“The same is true for canned light tuna unless you’re purchasing from a company that checks the mercury levels of each can. But very few companies currently take this extra step.”

3. Imported catfish

“Ninety percent of catfish are imported. They often come from contaminated waters, and may contain dangerous chemicals and antibiotics,” cautions Ms. Zumpano.

So if you love your catfish, choose farm-raised varieties from American waters. “Or try Asian carp, which has a similar taste,” she suggests.

The next time you’re weighing dinner options, follow these tips for choosing fish that are high in omega-3 and low in mercury, safely sourced and sustainably caught. “When purchasing canned fish, be sure that it’s BPA-free,” adds Ms. Titgemeier.

You’ll find yourself enjoying some menu options you haven’t tried before.

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