Farmed salmon: how safe, how healthy?

Philip J. Goscienski, M.D.

September 2010

Salmon is high on the list of foods that nutritionists recommend and for some solid reasons. It is high in protein, low in saturated fat and generously endowed with polyunsaturated (omega-3) fatty acids. In particular, the benefits of omega-3 fats have been confirmed since the revelation in the 1960s that they sharply reduce the risk of sudden cardiac death. These polyunsaturated fats are essential for normal development of the brain and eye.

High consumer demand has led to the cultivation of salmon on a large scale and it accounts for about half the worldwide production of this popular fish.

Unlike some of the larger species of fish that are high on the food chain, salmon is relatively free of mercury and other toxic chemicals, although there are some exceptions.

Wild salmon feed on smaller fish, other sea creatures and insects. In the expanse of the ocean, where they spend most of their lives, they tend to be free of disease. Besides humans, salmon face ocean predators, including killer whales and sharks. In their spawning runs they provide meals for bears, birds of prey and enthusiastic sportsmen.

Farmed salmon are free of these large predators but subject to tiny ones. Their crowded environment predisposes to infection and few get to market without antibiotics. They feast on grains and chicken parts, foods unknown to their wild cousins, or fish meal, which eliminates an active chase and requires little expenditure of energy. Some salmon enthusiasts feel that these semi-sedentary salmon, like human couch potatoes, have flesh that is less firm and tasty. Like their human counterparts their bodies contain more saturated fat.

Almost all the salmon that comes from the North Atlantic is farm-raised and it is often contaminated with PCBs (polychlorinated biphenyls) and dioxin, chemicals that have cancer-causing properties. To be fair, the increased risk of cancer from this source is quite small compared to other foods.

Small amounts of mercury are occasionally found even in wild salmon. The level has always been so low, whether wild or farm-raised, that there is no danger even to high-risk persons such as pregnant women and small children.

The healthiest and safest salmon is that which comes from Alaska and the Pacific Northwest. But as pollution spreads and testing facilities identify more cancer-causing chemicals, even this may eventually need re-evaluation. Until then, salmon remains an excellent nutritional staple whose heart-healthy benefits far outweigh the risk of cancer.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at