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These polyunsaturated fats, found in all cell membranes, help cells communicate with one another and have been linked to a lower risk of many conditions.
“Omega-3s have been shown to reduce blood clots [which can cause heart attack or stroke] because they prevent blood platelets from getting sticky,” says Julia Zumpano, a dietitian at the Miller Family Heart & Vascular Institute at the Cleveland Clinic. “They also lower triglycerides — fat that can accumulate in the arteries — reduce blood pressure and inflammation, and increase levels of good cholesterol.”
Omega-3 fatty acids also appear to help prevent other problems that can come with growing older, such as muscle and bone loss — and possibly even cognitive issues. The health effects are so widespread that a 2018 study of older adults published in the journal BMJ found that having higher blood levels of omega-3s from fish is linked to healthier aging — reducing the risk of having a chronic disease or serious mental or physical problems by 24 percent compared with having low levels.
Fish vs. supplements
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 efficiently.
Fish oil supplements contain EPA and DHA, too, but most studies have not found pills to be as helpful as simply eating seafood.
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, senior research scientist at the New York Academy of Medicine.
The mercury problem
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, which 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.
Fortunately, there are many fish that are low in mercury and high in omega-3s, as “Pick your fish” shows.
Solutions for the fish-averse
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, says Jean Halloran, former director of food policy initiatives at Consumer Reports. 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.”
Pick your fish
How to make the healthiest choice? The following list of fish is organized into two healthy groups, depending on their omega-3 content, and one group to avoid.
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
Omega-3s in Rx form?
It may be reasonable for a doctor to prescribe an Rx form of omega-3s to patients with high triglycerides, Siscovick says. A recent study found that giving 4 grams of EPA supplement a day to people with high triglycerides who had cardiovascular issues and were on statins led to a 25 percent reduction in heart attacks compared with a placebo group. But for others, there’s not enough evidence to show a megadose would be helpful, Siscovick says.
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