Your Guide to Healthy Seafood Choices

To get the health benefits of omega-3s, the American Heart Association recommends eating at least two 3½-ounce servings of nonfried fish per week. Fish supplies the two types of omega-3s that studies suggest have the greatest health benefits: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linolenic acid (ALA), another omega-3, is found in plant foods such as chia seeds, flaxseeds, walnuts, soybeans, and certain vegetable oils. Our bodies can turn ALA into EPA and DHA, but not very efficiently.

Fish oil supplements contain EPA and DHA, too, but most studies—and many have been done over the years—have not found pills to be as helpful as simply eating seafood for most people. For exam­ple, a 2018 analysis of studies involving a total of 77,917 men and women at high risk for cardiovascular disease published in the journal JAMA Cardiology found no benefit to taking omega-3 supplements, even in people who had diabetes or prior heart disease. Moreover, when you opt for pills over fish, you don't get the other nutrients fish contains. "Some of the benefits of fish may be because it replaces meat in your diet, so I'd skip the supplements and spend the money on a salmon dinner," says David Siscovick, M.D., senior research scientist at the New York Academy of Medicine in New York City.

One concern about upping your fish consumption is that it can also mean you increase your intake of mercury. You've probably heard that pregnant women and young children should avoid this heavy metal (it can cause damage to developing brains), but it's a misconception that you age out of the threat of mercury overload. In adults, it can cause neurological problems and result in memory loss, weakness and numbness, and tremors.

"Mercury is in oceans and rivers naturally, and due to pollution," says Jean Halloran, director of food policy initiatives at Consumer Reports. "It accumulates in the flesh of large, long-lived fish, such as the bigeye tuna often used in sushi and swordfish." Fortunately, there are many fish that are low in mercury and high in omega-3s, as "Pick Your Fish," below, shows.

In the end, the healthiest fish may simply be the kind you actually eat. But fish poses some obstacles for many people:

Cost can be a concern. Seafood can be pricey, but inexpensive options are available, Halloran says. For example, some of the cheapest fish, such as anchovies and sardines, are also tops in omega-3s. "And canned salmon is not only economical, it's all wild-caught Alaskan salmon, which is the healthiest type," she says. She also says light chunk canned tuna is a better pick than pricier albacore because it's a low-mercury option.

Cooking fish can feel intimidating. People who don't live in a coastal area where fish is readily available or who didn't grow up eating a lot of fish might not have the first idea about how to prepare it. "And if they have a couple of bad fish-eating experiences," Zumpano says, "that can really deter them." To get started, Halloran recommends taking a filet of flounder or sole—or whatever healthy fish you like—drizzling olive oil on both sides, squeezing a little lemon on top, and broiling until it turns opaque and flaky. And of course, a salmon or tuna salad sandwich will give you fish points for the week. Zumpano also recommends ordering fish at restaurants. "Most Americans eat out at least once a week," she says, adding that we also tend to take in more calories when we do. Getting broiled fish can help safeguard against that.

Fish tastes like fish. Let's face it: There are some inveterate fish haters among us. But Halloran suggests giving it one more shot. "Fish goes bad quicker than anything, so make sure that what you're getting is really fresh," she says. If you can, buy from a market that gets fresh shipments daily. Fish should smell mild and clean, not fishy or sour. Filets shouldn't be discolored or dry around the edges, and the flesh should be firm and should spring back when pressed. For whole fish, look for clear, shiny eyes.

What if the fish you like is lower in omega-3s? Eat it anyway. "It's still good for you," Zumpano says, "and variety is important."

How to make the healthiest choice? We've organized the following low-mercury fish into two healthy categories, depending on their omega-3 content: "Great Choices" have the most omega-3s, and "Good Choices" have less but are still healthy. "Eat Rarely, If Ever" fish are high-mercury types you should have only once in a while, if at all.

Great Choices: High in Omega-3s

 • Anchovies
• Atlantic mackerel
• Herring
• Oysters
 • Pacific chub mackerel
 • Sardines
 • Shad
 • Trout
 • Wild and Alaskan salmon (canned or fresh)

Good Choices: Lower in Omega-3s
(but still healthy)

 • Atlantic croaker
 • Canned light tuna
 • Catfish
 • Crab
• Flounder and sole (flatfish)
 • Haddock
 • Lobster
 • Mullet
 • Pollock
• Shrimp (wild and most U.S. farmed)
 • Tilapia
 • Scallops
 • Squid (wild)

Eat Rarely, If Ever: High in Mercury

 • Bigeye tuna
• Gulf tilefish
 • King mackerel
 • Marlin
 • Orange roughy

It may be reasonable for a doctor to prescribe an Rx form of omega-3s to patients with high triglycerides, Siscovick says. In the REDUCE-IT trial, a recent study of 19,212 people, Siscovick says, "the question they asked was whether, if you gave 4 grams of EPA supplement a day to someone with high triglycerides who had cardiovascular issues and was on statins, they would benefit."

In short, the answer was yes. These people had a 25 percent reduction in heart attacks compared with a placebo group. But for others, Siscovick says there's not enough evidence to show a megadose would be helpful. And even when an Rx might be considered, he says that per the American Heart Association, doctors should first treat conditions that may contribute to elevated levels, such as poorly controlled type 2 diabetes or hypothyroidism.