Salmon and salmon oil are often the first foods recommended for a daily dose of Omega 3. Being high in protein, potassium, Vitamin B and EPA/DHA (two active forms of Omega 3), salmon is indeed a great source for a lot of good stuff! While we’re not here to pick a fight with salmon oil, we do want to give you the lowdown on why we opt for anchovy and krill oil over salmon oil.
Here’s the deal. Above, you can see the food chain (approximately – a salmon’s diet can vary based on location) of a salt-water salmon. Being near the top of the food chain, salmon run the risk of containing higher amounts of heavy metals. A salmon will eat all the fish in front of him, absorbing everything they ate (including the even smaller fish THOSE fish ate), toxins and all. On the other hand, anchovy and krill are nearer the bottom of the chain, presenting a lower risk for contamination of toxins and heavy metals.
Biomagnification: How It Happens
Waters become contaminated due to water pollution from mining, which releases mercury & methylmercury into oceans, rivers, etc. While the release of these toxins is generally in very small concentrations at a time, fish are really good at absorbing it quickly (and not so great at excreting it). So, instead of being released, mercury accumulates in the tissue of the fish and continues to accumulate as the fish continues to… well, be alive. The level of contamination increases the higher up the food chain you go (as well as with the increasing age of the fish) because fish are absorbing more and more mercury—both from the water and from the consumption of other fish who’ve accumulated mercury—without the ability to get rid of it.
This is a phenomenon known as biomagnification – when a toxin becomes more and more concentrated in an organism higher up on the food chain.
Take a look at those tiny frowny faces up there. They represent the presence of mercury or methylmercury in our fish friends. On the far right, you have the krill (let’s call him Kevin) and anchovy (Arthur). Kevin and Arthur typically feed on plankton or single-cell plants and spend most of their time trying not to get eaten by anything else. While Kevin and Arthur do have some mercury accumulation in their tissue, it’s only the bare minimum amount that comes with just living in polluted water. In comparison to the rest of the ocean’s population, their levels of mercury are impressively low.
Moving further up the food chain, we find herring and eel (and for continuity of humanization, let’s call them Harold and Eric). While Harold and Eric do also feed on plankton, algae, and other plants, they eat the smaller fish in addition. In eating these smaller fish, the mercury levels within their tissue are a little bit higher than Kevin’s or Arthur’s, because they are absorbing Kevin and Arthur’s contaminated tissue, alongside the toxins in the polluted water.
Our next step up leaves us with the salmon (Sally the Salmon). Sally eats all those guys in front of her, absorbing all of their contaminated tissue, all the while still breathing in the polluted water. Sally’s mercury levels are much higher than any of those to her right. And, with her even longer lifespan, she has more time to eat more fish, breathe more toxins, and accumulate more mercury in her tissue. She’s got it bad.
So, to sum up:
While salmon oil is not by any means bad for you or your pet, it does present a higher risk of toxins than the lower fish. All three fish oils are great (non-plant) sources of EPA and DHA, which, going back to our fat charts, is best for carnivores who lack the ability to convert ALA to EPA and DHA. (If all of that seemed like a bunch of mumbo jumbo to you, take a peek at the omegas post to clear up the confusion).