8 healthiest fish to eat, and 4 to avoid

Doctors and dieticians often advise: “Eat more fish.” Specifically, eat fish at least two times per week as part of a healthy diet, the American Heart Association recommends. But there are many fish in the sea (and in rivers and lakes), so which fish should you eat? Are some fish healthier than others? Are some fish not good to eat? Bottom line: Which are the “best” fish to eat?

To find out, MDLinx talked with Julia Zumpano, RD, LD, a registered dietitian specializing in nutrition therapy for preventive cardiology and rehabilitation at the Center for Human Nutrition, Cleveland Clinic, Cleveland, OH.

One fish, two fish, bad fish, good fish

“All types of fish are good sources of protein and B vitamins,” Zumpano explained. “These fish [listed below] are high in an essential fatty acid, omega-3 fatty acid, which has several health benefits. It reduces blood pressure, inflammation, triglycerides, platelet aggregation, arterial plaque formation, and the risk of blood clots. And it raises HDL cholesterol.”

Omega-3 fatty acids are found in every kind of fish, but they are especially high in fatty, oily fish. Because many of these fish live in cold waters, the meat has a high fat content and is rich in fatty acids—healthy polyunsaturated fats. But, they’re low in saturated fat and high in protein. These fish are also good sources of vitamin D, selenium, phosphorus, iron, and iodine.

The 8 healthiest fish that Zumpano recommends:

1. Salmon. The flesh of this oily fish has a characteristic orange to red color. Salmon is a rich source of omega-3 fatty acids, B vitamins (especially vitamin B12 at 133% daily value [DV]), selenium, and phosphorus.

2. Mackerel. Another oily fish, mackerel is a rich source of omega-3 fatty acids, vitamin D, magnesium, and phosphorus. Fresh mackerel spoils quickly, and unless properly refrigerated or cured, it should be eaten on the day it’s caught.

3. Herring. Highly rich in vitamin B12 (570% DV), herring is also a good source of niacin, vitamin B6, vitamin D, and phosphorus. Like other oily fish, it’s an excellent source of omega-3s. Herring is prepared in a variety of ways, such as pickled, dried, smoked, or salted.

4. Tuna. A saltwater fish, fresh tuna is notably featured as sushi. Canned tuna has been a food staple for more than a century. In the United States, canned “white meat tuna” is made exclusively of albacore. Canned light tuna is high in protein and a rich source of phosphorus and vitamin D.

5. Lake trout. Freshwater trout is low in calories but high in protein. A healthy source of omega-3 fatty acids, trout is also naturally rich in B vitamins (thiamin, riboflavin, and niacin), vitamin D, phosphorus, and iron. Trout is also a good dietary source of iodine.

6. Freshwater whitefish. Dwelling deep in icy northern lakes, whitefish have a high fat content and loads of omega-3 fatty acids. Although related to salmon, the flesh of raw whitefish is almost pure white (as its name implies).

7. Halibut. Noted for its firm texture and clean taste, halibut is a good source of protein. It’s also rich in selenium, phosphorus, vitamin D, and several B vitamins (niacin, vitamin B6, and vitamin B12).

8. Bass. Bass is a general term that encompasses a large number of fish, both freshwater and seawater. Popular species of bass include striped bass, largemouth bass, and sea bass. Like other fish on this list, bass are rich in omega-3s and protein. Bass are also a good source of manganese, phosphorus, and vitamin B12.

Different fish for different folks?

You may be wondering: Are any of these fish better for particular populations, like people with cardiovascular disease, pregnant/nursing mothers, children, the elderly, or people who want to lose weight?

“All of these fish are good for each of those populations,” Zumpano said.  

However, some of these fish can be high in mercury, notably mackerel and some tuna (bluefin and albacore), she added. One serving of one of these fish per week is OK for most people, according to the FDA. But pregnant/nursing mothers should completely avoid eating fish that are high in mercury, and should limit their consumption of other types of fish to 12 oz per week.

To prevent children from exceeding the safe limit for mercury, they should eat fish from the FDA’s “best choices” category two times a week according to these recommended serving sizes by age group:

• Age 2: 1 oz serving

• Age 6: 2 oz serving

• Age 9: 3 oz serving

• Age 11 and up: 4 oz serving

What fish to limit or avoid

“All fish do contain some mercury,” Zumpano explained. “Mercury occurs naturally in the environment and as a result of industrial pollution. It collects in the air and can collect in streams and oceans where it’s converted into methylmercury.”

She specifically named four fish with some of the highest levels of mercury—shark, tilefish, king mackerel, and swordfish—that should be limited or avoided.

On that note, are freshwater fish safer than saltwater fish?

“Not necessarily—it really depends on the condition of the water. Freshwater fish are exposed to mercury, dioxins, and PCBs [polychlorinated biphenyls] just as saltwater fish are,” she said. “It’s best to eat a variety of fish from both sources that are known to have the fewest contaminants. You can check your local fish advisories through the EPA.”

On the whole, the proven health benefits of fish outweigh the potential risks, researchers have found.

Best ways to cook fish

What’s the healthiest way to prepare fish? “Dry cooking methods are best, such as grilling, broiling, roasting, air frying, or poaching,” Zumpano recommended. “If you choose to sauté, limit it to a small amount of extra virgin olive oil on the lowest heat possible.”

To add flavor to dry cooking methods, remember that citrus pairs well with fish, she added. Use lemon, lime, or orange along with fresh herbs.

If fish is healthier than red meat, then is fish and chips healthier than a burger and fries? “No! Fish and chips are not healthier and actually may be unhealthier. Fried fish generally has a very thick breading on it (to prevent the fish from falling apart in the deep fryer), and the unhealthy oil is absorbed into the breading,” Zumpano said. “A traditional fish and chips dinner can have over 1,400 calories, 90 g fat, and 2,000 mg sodium. In comparison, a burger and fries dinner provides less calories, fat, and sodium.”

Not that you should eat a burger and fries as the “healthy” option. So, at your next backyard barbecue, grill or broil one of these eight healthy fish instead.