The American Heart Association recommends eating salmon or other fatty fish such as mackerel or tuna twice each week for the heart-protective benefits associated with omega-3 fatty acids found in their fish oils. The marketplace obliges, offering salmon wild caught, farm raised, canned, smoked, and brined. But according to USDA figures, there are nutritional differences, depending on the source and methods of preparation.
Farm-raised: Farmed salmon generally contains more calories, more fat and, consequently, more omega-3 fatty acids than wild fish (2.147 grams versus 1.059). Farm-raised flavors tend to be milder.
Wild Caught: Aficionados favor sea-running salmon for its more assertive flavor, particularly chinook and coho. And fresh salmon, both wild and farmed, deliver more protein than processed varieties (for example, 23 grams for wild coho versus 18 for smoked). Ask your fishmonger which is freshest since nutritional values degrade over time.
Canned: The most commonly canned species are pink and sockeye salmon. Between the two, the cheaper pink has the edge in higher omega-3 values (1.65 grams versus 1.15 grams), though the stronger-tasting, firmer textured, red-hued sockeye tends to win flavor comparisons. Soft fish bones found in canned varieties deliver high calcium levels, giving them a strong nutritional edge. Salt used to preserve the fish contributes to moderate sodium levels, though.
Smoked: Smoking preserves salmon by exposing it to high heat, resulting in smoky, flaky fish. To get the smooth texture associated with lox, salmon is dunked in salt brine and then "cold smoked" at a lower temperature for a longer time. Both smoking processes degrade protein, fat, and omega-3 values from fresh fish, and increase salt content significantly. Ordinary smoked salmon has 784 grams of sodium, and a typical serving of lox contains a whopping 2,000 grams, which is almost equal to the Recommended Daily Intake.
(Values reflect 3.5-ounce servings.)