By Marissa Lippert, RD

With summer on the horizon, seafood and fish often become coveted features on lunch or dinner menus—and thankfully so, since they’re low in calories, cholesterol, and saturated fat, as well as an excellent source of lean protein. However, concepts like wild vs. farmed, omega-3 fatty acids, and mercury content can easily send us spiraling into a fishy state of confusion. That’s why we’ve cracked the code on fish and seafood to help you choose the most healthful options. 

Why omega-3 fatty acids are good for you

Omega-3 fatty acids may sound like a lot of scientific jargon, but they boast a wealth of health benefits you don’t want to pass up. Omega-3 fatty acids are "healthy" polyunsaturated fats. And they come in a variety of forms: docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and alpha-linoleic acids ( ALA). These fats are essential to our diet, meaning that our bodies can’t produce them on their own, which is why we must get them from food.

Foods high in omega-3 fatty acids promote cardiovascular health; decrease blood pressure and inflammation; and aid prenatal and postnatal brain, neurological and vision development. Numerous research studies are also assessing the effectiveness of omega-3 fatty acids in the treatment of depression.

Cold-water fatty fish—such as salmon, mackerel, herring, sardines and albacore tuna—lead the pack when it comes to omega-3s. The American Heart Association recommends that individuals consume at least two 6 ounce servings of fish rich in omega-3 fatty acids per week to make the most of their health benefits. Other foods abundant in omega-3s include olive, canola and flaxseed oils, walnuts, avocados and ground flaxseeds. 

Eating fish: is there a risk of mercury toxicity?

You’ve likely seen the numerous warnings from the Food and Drug Administration (FDA) regarding mercury levels in certain types of fish and the associated toxicity risks. But don’t discredit all fish and shellfish just yet—there are plenty of healthful, low-mercury seafood choices that can make frequent appearances on your plate. However, keep in mind that some types of fish contain more mercury than others and you should steer clear of these.

Excess consumption of mercury may pose a risk to women of child-bearing age and to young children, causing damage to the developing brain, learning deficiencies and delayed mental development. As recommended by the FDA, women and young children should aim to consume a maximum of one serving (6 ounces) of “high-mercury” fish per week. That’s equivalent to one 6 ounce tuna steak, one can of albacore “white” tuna, or 1 serving of swordfish or sea bass. You can be more lenient with fish in the low to medium category, consuming up to 12 ounces, 2-3 servings per week. Expectant and new mothers should limit mercury consumption as much as possible.

When & why to buy wild over farmed foods

Now that you’ve got omega-3s and mercury levels sorted out, we’ll tackle why to choose wild over farmed.

Wild fish are grown and caught in their natural environment (lakes, rivers and oceans) as opposed to farmed fish, which are raised in man-made conditions. Farmed-raised fish are frequently found to contain higher levels of contaminating toxins such as polychlorinated biphenyls (PCBs) and dioxins which are present in their feed. Farming practices may also alter the taste and color of fish. Farmed salmon for instance, are generally paler-pink, have a more distinct fishy flavor and are slightly fattier than their wild counterparts. Wild fish and seafood may be accompanied by a higher price tag. For a break on higher costs, look for wild salmon during peak season, May through September. 

Seafood cheat sheet (per 3 ounces serving)