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Ask the Diet Doctor: Farm-Raised vs. Wild Salmon

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Q: Is wild salmon better for me than farm-raised salmon?

A: The benefit of eating farmed salmon versus wild salmon is hotly debated. Some people take the stance that farm-raised salmon is devoid of nutrition and pumped full of toxins. However, the differences in farmed versus wild salmon have been blown out of proportion, and in the end, eating either type of salmon is better than none at all. Here's a closer look at how the two types of fish stack up nutritionally. 

Omega-3 Fats
You may have heard that wild salmon contains higher amounts of omega-3 fats. This just isn’t true. Based on the most recent data in the USDA food database, a three-ounce serving of wild salmon contains 1.4g of long chain omega-3 fats, while the same size serving of farm-raised salmon contains 2g. So if you are eating salmon to get more omega-3 fats in your diet, farm-raised salmon is the way to go.

RELATED: How Cooking Fish Affects Omega-3 Levels

Omega-3 to Omega-6 Ratio
Another purported benefit of wild salmon over farm-raised is a ratio of omega-3 fats to omega-6 fats more in line with optimal health. This is sort of a trick statement, because this sort of ratio has little impact on your health—the total amount of omega-3s is a better predictor of health. In addition, if the ratio of omega-3 to omega-6 fats was relevant, it would be better in farmed salmon. In farm-raised Atlantic salmon this ratio is 25.6, while in wild Atlantic salmon this ratio is 6.2 (a higher ratio suggests more omega-3 fats and less omega-6 fats).

Vitamins and Minerals
For certain nutrients like potassium and selenium, wild salmon does contain higher amounts. But farmed salmon contains higher amounts of other nutrients like folate and vitamin A, while other vitamin and mineral levels are the same between the two types. Overall the vitamin and mineral package that these two types of salmon contain is similar, for all intents and purposes.

Contamination
Fish, especially salmon, is a very nutritious food. A higher intake of fish in the diet is generally associated with less chronic disease. The one negative: The toxins and heavy metals found in fish. So for many people eating fish, this requires a cost/benefit analysis. But when researchers looked as the benefits and risks of eating fish with respects to mercury exposure, the conclusion was that the benefits greatly outweigh the risks, especially with salmon which contains low levels of mercury compared to many other fish.

RELATED: The Best and Worst Sushi for Weight Loss

Polychlorinated biphenyls (PCBs) are another chemical toxin found in both wild and farmed salmon. Farmed salmon generally contains higher levels of PCBs but wild salmon is not free of these toxins. (Unfortunately PCBs and similar toxins are so ubiquitous in our environment they can be found in the dust in your house.) A 2011 study published in Environmental Science & Technology reported that different factors such as lifespan of the fish (chinook salmon live longer than other types) or living and feeding close to the coastline can lead to PCB levels in wild salmon near to that found in farmed salmon. The good news is that cooking fish leads to the removal of some of the PCBs. 

The takeaway: Eating either type of salmon will benefit you. In the end, Americans just don’t eat nearly enough fish and when they do, it is usually some nondescript white fish molded in a rectangular shape, battered, and fried. In fact, if you look at Americans’ top protein sources, fish shows up 11th on the list. Bread ranks fifth. Yes, Americans get more protein in their diets from bread than fish. You are better off eating quality farm-raised salmon (without added dyes to enhance the coloring of the fish!) than no salmon at all. However if you eat salmon frequently (more than twice a week), then it may be worth buying some wild salmon to minimize exposure to excessive PCBs.

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