If you relish eating salmon sushi and filets, and think you are being healthy in doing so, you will disappointed to learn of some nasty truths about this luscious fish. In Egypt, the salmon we consume is mostly farmed salmon (reared in a salmon farm) while wild salmon (caught in the wild) is a rare find, and in other countries is always labeled as it is far more expensive than farmed salmon.
Salmon farms account for over 50% of the salmon consumed worldwide and are a major concern for our health as well as our environment, comprising a concoction of chemicals and waste in the pursuit of profit. Over the past two decades, salmon farming has become a billion dollar business stretching from Norway to Chile with world production of farmed salmon having grown from 5,500 tons a year to more than 660,000 tons, according to the World Wildlife Federation…
Salmon farms comprise vast cages usually situated at the mouths of sea lochs where the salmon are very densely packed. This dense housing leads to abundant infectious diseases and lice infestations that become endemic and ongoing and are treated with toxic chemicals and pesticides, that may be legal or illegal (e.g. Ivermectin, an ant parasitic neurotoxin and Dichlorvos, linked to pancreatic tumors, leukemia and brain cancer have been banned from use but are still found in some salmon farms around the world). Sea lice occur naturally in wild salmon at a rate of 5 or 6 lice, but farmed salmon are not so fortunate and may have up to 1,000 lice, some of which escape into the wild infecting and killing juvenile salmon and reducing the number of wild salmon. These salmon farms also lead to dumping and accumulation of untreated and contaminated waste, feed, and chemicals to the aquatic environment, which can destroy the marine habitats and cause marine poisoning (such as amnesiac shellfish poisoning, an irreversible disease than can cause brain damage in humans). The sewage output from a salmon farm is like the sewage output of 9.4 million people, according to the World Wide Fund for Nature (WWF). Furthermore, the tidal flushing of these contaminants from the cages is so poor that it has been compared to flushing your toilet every two weeks.
What the salmon are actually fed further contaminates the salmon; farmed salmon are fed pellets made up of fish oil and fish meal (the leftover bits of smaller fish such as herring, mackerel and anchovies) that contain toxic chemicals ingested by the smaller fish. These chemicals include organic pollutants such as dioxins, polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) which although banned in many countries, remain in the environment due to their long half life (time it takes for half the chemical to biodegrade). These substances are concentrated in the fat and skin of the fish, and the intense feeding regimen of the salmon (with the pellets that contain up to 25% fish oil to fatten the salmon) concentrates these chemicals in the salmon. A predator like salmon naturally accumulates more PCBs in its fat than fish lower down in the food chain but whereas wild salmon will scavenge the ocean for nutrients, farmed salmon receive a concentrated dose of pollutants.
A study published in 2004 in Science that analyzed farmed salmon from around the world for different contaminants found that farmed salmon had over ten times the level of these contaminants found in wild salmon. The researchers recommended eating a salmon meal once every five months as these chemicals break down slowly (half life of 10 years) and accumulate in our bodies as we continue to ingest them. The chemicals are not excreted in sweat or urine but only in breast milk, and as these chemicals cause developmental problems in the fetus, and learning difficulties in children, the study also recommended that women of all ages be particularly prudent when it comes to eating farmed salmon. These chemicals further increase the risk of cancer and cause immune system dysfunction in humans. Even more toxic substances are added to farmed salmon to give it is orange/pinkish color, as unlike its wild relative, farmed salmon is grey.
With all the pollutants resulting from farmed salmon, but with the known benefits of salmon for the heart (omega 3 fatty acids in salmon protect against heart disease), we are faced with a dilemma on whether or not to eat salmon, and if so, how much is safe?
Each health agency allows for different safely levels of toxins in foods and the World Health Organisation (WHO) has the lowest level allowing a monthly intake of 70 picograms of dioxins and dioxin-like PCBs. This allows for one or two portions of farmed salmon per week, but does not take into account the inclusion of other dietary sources of these substances. Furthermore, each salmon farm has different levels of these toxins, so evaluating your levels would also entail knowing which country and which farm your salmon came from. European farms are more contaminated than those in America.
Fresh wild fish are abundant in Egypt and make steering away from salmon an easy choice. Moderating your intake of salmon and increasing your omega 3 from other sources (from walnuts, soy, and flaxseeds) may be the best choice, especially if you care about the environment.
Dr. May El Meleigyholds a Ph.D in Immunology from the London School of Hygiene and Tropical Medicine, as well as an MSc. (Toxicology/Pathology) and a B.Sc in Pharmacology) from London University. El Meleigy is a freelance medical/health writer and is currently producing Health Education programs for Egyptian TV.
