Nutrition Showdown: Farmed vs Wild salmon

This is the first in a series of guest blog posts I wrote for Skipper Otto's Community Supported Fishery. The original post can be found here and was published June 21, 2017.

We’ve all seen the headlines and heard about what a nutritional powerhouse salmon is:

“Salmon the everyday superfood!”
“Top 10 reasons to eat more salmon!”
“Why you aren’t eating enough salmon!”

Salmon is credited for everything from decreasing inflammation(1), lowering blood pressure(2), and reducing cancer risk(3). But is all salmon created equal or does farmed salmon differ nutritionally from wild-caught salmon? Let’s take a closer look.

There are a few key differences between farmed and wild salmon.

Farmed salmon have a higher fat content than their wild counterparts which means it has more calories and less protein per serving, and a higher omega-3 essential fatty acid (EFA) content.  You’d think higher omega-3s would be a good thing and mean more omega-3 per serving. Not exactly.

You can’t get one without the other
Nutritional assessments have found more omega-3s per gram in farmed compared to wild salmon, but farmed salmon also comes with a substantial serving of omega-6s. We then need to factor in that omega-6s and omega-3s compete for the same receptors in our bodies(4). So looking to the ratio of omega-3:6 as opposed to total omega-3 is essential when assessing health and nutritional benefits. When we do that, we can see that wild salmon have a significant nutritional advantage with a 14:1 ratio vs the 3:1 ratio of farmed salmon (see table).

You may ask “What’s so bad about omega-6? Aren’t they also an ‘essential fatty acid’?”
Yes, but…

Omega-6 and omega-3 are both EFAs, which means they are essential for the body and need to be consumed via the diet. Throughout history, humans ate a diet where EFAs were balanced. But over the past century, dietary shifts have resulted in significant increases in our consumption of omega-6s and decreases in our consumption of omega-3s. This has resulted in increased prevalence of weight gain, obesity(5), and chronic inflammation(6) due to the difference in response that omega-6 EFAs elicit in the body compared to omega-3s.

With great fat, comes great responsibility
Increased fat in farmed salmon brings other things with it. Farmed salmon have been found to have significantly higher concentrations of “fat-loving” contaminants as PCBs, dioxins, and pesticides(7), most likely due to their feed. While it has been argued that the benefits of consuming omega-3s from farmed salmon outweigh the health risks of contaminants, why risk it if you can eat wild salmon instead of farmed?

Bottom line: wild salmon wins over farm salmon from a nutritional standpoint, whether it be based on contaminant levels, healthy fats, or overall micronutrient density.

 

© Melissa Evanson 2017.  For permission to reproduce or repost this post, email melissaevansonrhn@gmail.com

Originally published on Skipper Otto Community Supported Fishery Blog: http://skipperotto.com/nutrition-showdown-farmed-vs-wild-salmon/ 

 

References:
1 https://www.ncbi.nlm.nih.gov/pubmed/24860193
2 https://www.ncbi.nlm.nih.gov/pubmed/26817716
3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4418048/
4 https://www.ncbi.nlm.nih.gov/pubmed/25373089
5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808858/
6 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335257/
7 https://www.ncbi.nlm.nih.gov/pubmed/16323755