Salmon is known to be good for your health. “Fish is one of the few animal foods that is consistently associated with health benefits, and when I recommend fish to people, salmon is at the top of the list,” said Tufts University Distinguished Professor and Director of the Food is Medicine Institute Darriush Mozaffarian said.

But which salmon to choose for health reasons—sockeye or coho, wild or farmed—is less obvious. Researchers found that there are also differences in the nutritional value of different species of salmon. Some consumers believe that the nutritional content and pollution levels of farmed and wild salmon are different, and this view is supported by some research.

From healthy fats to heavy metal contamination, here are the answers to all your salmon-related questions.

What Are the Benefits of Salmon?

Mozaffarian emphasized the omega-3 fatty acids (especially EPA and DHA) that are characteristic nutrients of salmon. Salmon contains more DHA and EPA-like omega-3 fatty acids than almost any other food except fatty fish like herring and sardines.

Studies agree that consuming the Omega-3 fatty acids in seafood can reduce the incidence of stroke and heart disease. Studies have shown that these fatty acids can reduce the level of arteriosclerosis associated with high blood pressure and may also have anti-inflammatory effects that may prevent obesity and type 2 diabetes.
Mozaffarian also said that Omega-3 fatty acids are crucial for early brain development, and new evidence shows that regular intake of Omega-3 fatty acids can prevent age-related cognitive decline and Alzheimer’s disease.

He said that while the body can produce certain amounts of DHA and EPA on its own, foods rich in omega-3 fatty acids can help ensure that the body and brain get the nutrients they need. The American Heart Association recommends eating at least 85 grams of fish (especially fatty fish like salmon) twice a week.

While many supplements also contain omega-3 fatty acids, evidence suggests that consuming these fats from seafood may be better, perhaps because compounds in fish help prevent the omega-3 fatty acids from being broken down by digestion.

In addition, experts say salmon also contains other nutrients, such as protein, selenium, and iodide, that may support or enhance the health benefits of these fats. “People often emphasize the omega-3 fatty acids, but salmon is so beneficial because of its comprehensive nutritional profile,” said Matthew Sprague, a lecturer in nutrition at the Institute of Aquaculture at the University of Stirling in the UK.

Do Different Salmon Have Different Nutritional Values?

“There are so many choices out there that it can be confusing,” says Stephanie Colombo, associate professor, and research director of aquaculture nutrition at Dalhousie University in Canada.
To clear up some of the confusion, Colombo looked at the nutritional value of the various types of salmon available to consumers. “There’s not much difference between wild and farmed salmon, which was the main finding of our study,” she said.

While wild sockeye and wild king salmon, the two most commercially available varieties, are the most “nutrient-dense,” her research also found that farmed Atlantic salmon only has just as much omega-3 fatty acids, protein, and other healthy components. Wild Pacific pink salmon tends to have lower levels of these nutrients than other species—both farmed and wild.

However, the nutritional data from the Colombo study are average. Different species of salmon may have different levels of healthy fats or other nutrients based on factors such as the type of feed farmed salmon are fed and the time of year when wild salmon are fished, she said.

Colombo added, “All the salmon we studied were very nutritious.”

As for mercury and other contaminants, Colombo said his paper did find some differences between varieties. For example, farmed Atlantic salmon tends to have lower mercury levels than wild varieties. However, the mercury levels in all salmon samples were well below international safety standards. “Even if you eat salmon every day, you don’t have to worry about mercury poisoning,” she said.

The same goes for polychlorinated biphenyls (PCBs) and other contaminants sometimes found in seafood. The study found that these toxins did not reach harmful levels in either wild or farmed salmon. Mozaffarian said part of the problem is that salmon don’t live long enough to absorb large amounts of these toxins.

For those concerned about the ecological impact of their dietary choices, eating salmon can come with some psychological toll: Overfishing of wild fish and pollution from farmed fish are ongoing concerns. However, experts say all salmon species are better than most animal-based protein sources when it comes to their environmental footprint.

Colombo recommends purchasing salmon with a Marine Stewardship Council (MSC) or Best Aquaculture Practices (BAP) certification label. “If it’s certified salmon, you can have more confidence that it’s sourced sustainably and ethically,” she said.

Best of all, experts have confirmed that all salmon is good for you, so there’s no need to get hung up on which one is the best. “If you like the flavor of a certain salmon,” Mozaffarian says, “that’s the right salmon for you.”