Farmed salmon is losing its nutritional value, a new study has warned.
Scientists have found the amount of fatty acid omega-3 has dropped by half over the past 10 years, which means it may no longer be a key food in helping combat the likes of diabetes, heart disease and arthritis. Omega-3 is also key in helping boost children’s brain development.
Professor Douglas Tocher, a professor of nutrition at Stirling University, and his team looked into the natural benefits of farmed salmon, noting that in 2006 a 130g portion of the fish contained the recommended weekly intake of 3.5g of omega-3. However, in 2015, the same portion contained a mere 1.75g.
The professor believes the levels have dropped due to different feed used at the farms, as during the previous levels the salmon were fed small fish like anchovies and fish meals. However, after complaints from environmentalists regarding salmon eating too many smaller fish, dubbing it overfeeding, the feeding was altered.
“Ten years ago people were complaining about the level of marine ingredients in salmon feed,” Professor Tocher stressed. ”Now, the majority of materials in feed are plant-based – it’s the complete opposite. The consequence of this is the level of omega-3 will go down.”
In 2013 salmon was the most popular fish in the world, taking 17 per cent of the sales for the total traded value of seafood, and it’s these demands which have led to the salmon being fed less oily fish as there isn’t enough to go around. Up to 80 per cent of salmon’s diet was made up of oily fish back in 2006, whereas now it’s just 20 per cent.
But that’s not to say we should now shun the fish.
“I don’t want this to sound negative. Despite everything, farmed salmon is still the best source of long chain omega-3s. Even with the fall, they still have more (omega-3) than wild salmon,” the professor added of his findings, published in journal Scientific Reports.