Cod liver oil

By Safina Center Fellow and Writer in Residence Paul Greenberg

When the weather turns cold in the Northeast, my thoughts inevitably turn to codfish. This is the only time we New Yorkers get a real shot at these golden speckled beauties. As recently as a century ago, they could be caught off the piers at Coney Island. Now a much longer jaunt is required. A half year shy of my 50th birthday I wonder if my joints are still resilient enough to handle 12 hours at the rails of the Viking Starship in Montauk? Will it get cold enough for the Point Lookout boats to take a shot at the cod closer to home? These are my usual thoughts about cod, come January.

But this year as I sit revising my forthcoming book on omega-3 fatty acids, I find myself thinking about cod in a different way. For, really, it is cod liver oil that began the whole craze for Omega-3s, and the tracing of that history has led me down some fascinating avenues.

Cod, unlike more active fish, store their omega-3 fatty acids in high concentrations in their livers. This allows them to shuttle essential oil easily over to their gonads when it becomes time for reproduction. The easily available oil in the cod’s liver also makes it easy to extract even with primitive industrial processes. Early Scandinavians found that merely submerging the livers in casks of seawater caused the oil to detach from the tissues of the organs and float to the surface.

Very early on researchers were able to associate cod liver oil with a disease that had become increasingly prevalent as the industrial revolution spread throughout England. As the smog of the factories blackened the skies and taller and taller buildings blocked the sun malnourished children without ample sunlight in urban slums would often end up bowlegged by adolescence. A condition which physicians came to term “rickets.”

In the first part of the 18th century the Royal Infirmary in Manchester reported that cod liver oil appeared to be effective in curing rickets and one Samuel Moore found a similar affect with using an ointment derived from shark liver oil. A German observational study by drs. Schenk and Schutt described a successful five week course of cod liver oil curing the dreaded disease.


Cod liver oil processing. Photo: Public domain

Ever more numerous studies like these as well as anecdotal comparisons of marked health differences between Norwegians on the cod producing west coast and the more meat-focused easterners around Oslo prompted one Peter Möller to standardize the production of cod liver oil. Using a patented chemical process he arrived at a product that he announced to the world “didn’t taste fishy.” Ironically it took some time to get Scandinavians to accept the new industrially processed oil. As corporate historians of the inheritors of the Peter Möller brand put it “The consumers of cod liver oil had been used to the fact that ‘good medicine must taste bad’ and would not believe that the new and better quality was as healthy.”

A marketing campaign ensued and taking cod liver oil on a daily basis, regardless of whether one had a risk of rickets, became common practice. Because of this emerging tendency, Peter Möller built his company into an international phenomenon and ended his life with 70 cod liver oil steam factories producing 5,000 barrels of the stuff every year.

That there was actual medicinal value in cod liver oil has been proven without a doubt. Vitamins D and A are essential for human health and in undeveloped countries where access to proper nutrition is unavailable, an infusion of those vitamins through whatever vector is available is worthwhile. But the human mind in relation to curatives is imprecise and the transitive property often carries the day.

And so by the time the Danish doctors Hans Bang and Jørn Dyerberg drew blood from Greenland Eskimos in the early 1970s, there was already a predisposition among Scandinavians to believe that something magical existed within the oil of marine animals. When they discovered two peaks of two different omega-3s in Inuit blood they reached a perfectly logical decision to look for co-related health factors. When Bang and Dyerberg gathered health records from Greenland Inuits and compared them to Inuits living in Denmark and found remarkably different rates of heart disease, they formulated a hypothesis: that the consumption of marine animals, particularly those rich in omega-3 fatty acids affected the rate of cardiac disease. This is a classic example of what is called an “observational study.” Observational studies can lead to animal studies and eventually clinical trials on humans which, if all goes well, can lead to major changes in human health.

But, as I was to learn the more I delved into these oily depths, an observational study is just the beginning. . . .

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Paul Greenberg is author of a forthcoming book on omega-3 fatty acids and the marine food web, titled The Omega Principle: A Journey to the Bottom of the Marine Food Web. It is due out by Summer 2018. The accompanying Frontline documentary is slated for release in early 2017.

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