Loaded with heart-healthy and brain-boosting omega-3 fats, salmon is among the healthiest, tastiest and most popular fish. However, there are certain types of salmon you should try to stay away from and certain questions you should always ask before buying. Here are 7 tips to help you buy the best salmon.
Honey-Garlic Salmon

Pictured recipe: Honey-Garlic Salmon

People love salmon. This should make doctors happy: U.S. Dietary Guidelines recommend Americans eat two servings of fish a week. It's loaded with heart-healthy, brain-boosting omega-3 fats. On top of that, there are so many different types of salmon and ways to serve them that it would be hard to get bored with this fish.

But that said, there are certain types of salmon that some people try to stay away from and certain questions that savvy shoppers always ask before they buy. To help you out, we answer seven common questions so you can buy the best salmon.

1. Wild or farmed?

The first choice you should make is whether to buy wild salmon (and all Alaskan salmon is wild-caught) or farmed Atlantic salmon (fishing wild Atlantic salmon is illegal in the United States). In most instances, I opt for wild salmon. Environmental groups like Seafood Watch and the Environmental Defense Fund, have put nearly all farmed salmon on their "red" or "avoid" list. The reason: many farms use crowded pens. That's where salmon are easily infected with lice, may be treated with antibiotics and can spread disease to wild fish (one reason Alaska has banned salmon farms). In addition, it can take as much as three pounds of wild fish (and fishmeal) to raise one pound of salmon.

However, there's some good news. Some farms are raising coho salmon (small Pacific salmon) in closed pens that reduce the impact on wild fish. Other farms are using feeds fortified with the omega-3 EPA, which helps cut back on the fish needed to raise salmon.

2. Should I buy organic salmon?

There is no USDA organic standard for salmon and no guarantee an "organic" label means anything except the salmon was farmed.

Walnut-Rosemary Crusted Salmon

3. Is fresh salmon better than frozen? What about canned or packaged salmon?

You can order fresh salmon by mail order or find it in your markets from June-September. Most fish is flash-frozen when caught to preserve its freshness and allow for shipping. Frozen salmon is good for up to four months when properly frozen and thawed overnight in the refrigerator. Canned wild salmon is an excellent and economical choice. Look for BPA-free cans or pouches.

4. Does salmon carry PCBs or other toxins?

Wild Alaskan salmon, which spend most of their lives in open oceans, generally have very low levels of toxins. Coastal and farmed salmon, depending on the fish and meal they are fed, may have higher levels. The Environmental Defense Fund lists farmed Atlantic salmon as an "Eco-Worst" choice and recommends people eat no more than 2 servings a month due to high PCB levels.

Walnut-Rosemary Crusted Salmon

5. Do different types of salmon taste different?

There's a wide range of price, color and taste among the six species of salmon we commonly eat, so it depends on your budget, what's available and the recipe you have in mind. Here are the different types of salmon:

Chinook: The largest (and often most expensive), the king or chinook, is prized for its high fat content and buttery texture and is rich in omega-3s.

Sockeye: An oilier fish with deep red flesh, sockeye salmon also high in heart-healthy omega-3s but has a stronger flavor and stands up well to grilling.

Coho: Coho is milder and often lighter in color.

Pink and Chum: These are smaller fish and most often used for canned or smoked salmon and are good budget choices.

Atlantic: Last, the most common fish you will find at the market, the species known as Atlantic salmon, is a farmed species. It has a rich, fatty taste but is not recommended by environmental groups (see question #1).

Miso-Maple Salmon

Pictured recipe: Miso-Maple Salmon

6. Why is some salmon more orange than others?

Ever wondered why salmon is orange? Thank carotenoids, the same pigments that make carrots orange. Those magical antioxidants combat the damaging effects of free radicals.

The carotenoid in salmon is a particularly potent antioxidant known as astaxanthin, which has been shown to protect against cardiovascular disease, cancer, inflammation, eye diseases, general aging and many other conditions. Astaxanthin is produced by phytoplankton, tiny plants that use it to shield themselves from ultraviolet radiation. Shrimp, krill and other tiny crustaceans then eat the phytoplankton and accumulate astaxanthin in their bodies (which is what makes them pink), and then salmon eat them and store the astaxanthin in their skin and muscles.

Sockeye, coho and king salmon have the deepest color orange whereas pink and chum are the lightest. Many farmed Atlantic salmon are given feed with astaxanthin and, in some instances, a manufactured pigment called canthaxanthin, to turn their flesh orange.

Poached Salmon with Fennel and Lemon

7. Are fattier fish healthier?

In the case of salmon, the answer is yes-in terms of both taste and health! Salmon is a fantastic source of DHA, the omega-3 fatty acid that is essential for brain development, which comes from phytoplankton.

DHA is stored in salmon's fat, most often in the belly, and one 4-ounce serving of salmon can dish up 2,400 mg of omega-3s. Larger species, such as king, and those that have longer upstream journeys, tend to store more fat and have more omega-3s. Farmed salmon are often fattier than wild salmon but that's because they are fed a diet that includes grains and vegetable oils high in omega-6 fats, which combat the beneficial effects of omega-3s in the body. However, the higher fat content (often as high as 16% versus 8% for wild fish) means the fish is easier to cook and retains its moistness.

By Lisa Gosselin and Rowan Jacobsen