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Comment by rsolva | Hacker News Reader

Fatty fish accumulates heavy metales and other unhealthy components and pregnant women in Norway is told to limit the intake. But it has been controversial, the industry is not happy with these recommendations!

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I can see this being sensible regarding, for example, swordfish, which is long lived apex predator. They get the bio accumulation of everything they eat. Farm salmon has a short life and a controlled diet. Where would they get heavy metals?

From what I understand the fjord are relatively enclosed ecosystems and tend to accumulate stuff from the human acitivies around it

From their food and over time, I assume? Since farmed salmon is fed and live a short life I would also assume that it has lower pollution levels than wild fish of similar size and composition.

You are exactly wrong. Farmed salmon has very high levels of heavy metals and PCB because the water where they are farmed is slow moving accumulate pollution. Wild ocean fish swim in the open ocean where overall pollution is less. That’s why if you buy omega 3 tablets it needs to be from ocean fish otherwise you’re getting a high level of toxic chemicals.

The US FDA meanwhile maintains this page:

https://www.fda.gov/food/consumers/advice-about-eating-fish

It tells you why a pregnant woman should eat some fish, and which fish are safest.

The metal in fish is a concern, but can be mitigated fairly well.

I thought this was true for tuna and somewhat never registered it might be true for salmon too. I need to look this up and update, thank you.

Generally speaking, heavy metals accumulate as you move up the food chain, so it will be true for any large fish.

Can you link to those recommendations? I can't find anything on the Norwegian public health sites specifically about farmed salmon.

It seems public health recommendations where walked back after the controversy in the early 2010's, so it is not an official recommendation anymore.

Here are some of the studies and debates from back then:

- Chronic Consumption of Farmed Salmon Containing Persistent Organic Pollutants Causes Insulin Resistance and Obesity in Mice (2011): https://journals.plos.org/plosone/article?id=10.1371/journal...

- Are environmental pollutants in the Norwegian diet harmful to children?: https://tidsskriftet.no/en/2017/02/perspectives/are-environm...

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