Wild vs farmed salmon: what's the difference?
Salmon is widely known for its excellent nutritional value. Not only is it a source of high-quality protein, vitamins, and minerals, it is a source of omega three, a polyunsaturated fat that the body cannot organically produce, and that we therefore have to acquire through diet.
The beginnings of farmed salmon
According to The Guardian, farmed salmon was first reared in Norway in the 1960s. Along with Norway, Chile and Scotland dominate production of the fish, which, the Guardian says, ‘is due to their preference of sheltered and tidal waters to maximize growth rates and ward off disease.’[i]
Farmed salmon versus wild salmon
There are some pretty dramatic differences between farmed salmon and wild salmon. If we compare half a fillet of wild salmon with the same amount of farmed salmon, the farmed variety contains significantly more fat. More omega three, a lot more omega six fatty acids, and three times the amount of saturated fat to be specific. Though omega three isn’t a bad thing, too much saturated fat can be. On average, Brits get 12.6% of their energy (kJ/kcal) from saturated fats, which is slightly above the 11% maximum recommended by the Government.
Not only is farmed salmon fattier, it contains almost double the calories of wild salmon. Half a fillet of wild salmon comes in at 281 calories, whereas half a fillet of farmed salmon comes is a whopping 412 calories.
The problem is, farmed salmon has expanded rapidly in the last two decades and now accounts for seventy percent of all the salmon we eat[ii]. This means that, though farmed salmon is by all means healthy, it might not be providing us with quite the number of benefits we think it is. For example, wild salmon is much higher in minerals such as potassium, zinc and iron. By consuming farmed salmon over wild, you could be cutting your mineral intake by almost 50%.
What you might not realise is that when it comes to omega three, we benefit from a specific ratio of omega 6 to omega 3[iii]. The ratio of omega 6 to omega 3 in wild salmon is far better than in farmed.
Dr. Sarah Brewer says, ‘Humans evolved on a Stone Age, hunter-gatherer diet of green plants, wild animals and fish which contained a ratio of omega-6s (from natural vegetable oils) and omega-3s (from oily fish) at a ratio of around 2:1 but in a typical Western diet the ratio is closer to 10:1.’
There is also the issue of contaminants
Polychlorinated biphenyls (PCB’s) are a nasty type of chlorinated pesticide, and one study, which investigated over 700 salmon samples from around the world, found that on average, the PCB concentrations in farmed salmon were eight times higher than in wild salmon[iv].
This varies between regions, but we do know that wild salmon contains much fewer contaminants than farmed.
Of course, wild salmon tends to be a lot more expensive than farmed. Both still have substantial benefits, but factors such as pregnancy could influence your purchasing decision. Supplements can be used as an addition to your diet, and will help to replace any vitamins lost due to the growing industry of farmed salmon.