Fake Cod Liver Oil

By Atom Bergstrom

Atom’s Blog

Know the source of what you allow in your mouth from soil to shelf and from sea to shelf.

Deception runs rampant in the fish oil business, and it’s been going on for over two hundred years.

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Dr. Kaayla T. Daniel (“Is your ‘cod liver oil’ from cod?,” 2019) wrote …

“In the cod liver oil industry, fraud has been a problem at least since the mid nineteenth century. The real stuff (Gadus morhua) has become increasingly expensive due to scarcity and overfishing, and unscrupulous manufacturers often substitute cheaper oils. As a result, many so-called ‘arctic cod liver oils’ derive from other fish, and some are diluted with vegetable oil besides.”

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William Argyle Wilson, M.D. (On the History and Uses of Cod-liver Oil in Pulmonary Consumption: And Other Diseases, 1868) wrote …

“There is, unfortunately, no test for the purity of cod-liver oil. The nearest approach to it is a test for liver-oils in general, which are found to yield a beautiful lake or crimson color when brought in contact with sulphuric acid. This is supposed to be due to the action of the acid on the biliary matters contained in the oil. The only value of this test is to distinguish the liver-oil from that procured from other part of the animal, as it reacts equally on good and bad cod-liver oil, and on the oil obtained from the livers of other fish. The only fish-liver oil likely to be mistaken for cod-liver oil, is that procured from the livers of the pollock, hake, and haddock. These fish are caught in large quantities on the New-England coast, from spring to autumn, when cod-fish are scarce, the season for the latter being from November to June. It is estimated that three haddock to one cod are taken the year through in Massachusetts Bay, and the oil obtained from their livers, as well as from all the hake and pollock caught, is sold under the name cod-liver oil, though greatly inferior in medicinal and other qualities.

“It becomes, therefore, a matter of importance to be able to distinguish pure cod-liver oil from these inferior liver-oils; but as there is no chemical test to guide us, it can only be done by a careful study of their sensible properties, which reveal slight differences in taste and smell, and more marked differences in density, cod-liver oil being much more dense than any of the other oils under consideration. Another marked difference in the oils, is in their affinity for oxygen — the inferior varieties of liver-oil being much more prone to absorb oxygen and turn sour or rancid.

“It might be supposed, a priori, that fish belonging to the same family, and caught in the same waters, would be found to yield liver-oil of similar properties, but that this is not the case is evident from the fact that curriers, who use large quantities of cod-liver oil in dressing leather, can not utilize the lighter and thinner liver-oils for the same purposes, and they will not ‘stuff’ the leather, and render it permanently soft and pliable.

“When, however, it is known that cod-fish are caught in cold weather and on rocky bottom, and hake, haddock, and pollock in warm weather, on muddy bottom, and that they have preferences for different kinds of food, it does not seem unaccountable that their livers should yield oil of dissimilar properties. Shark-liver oil closely resembles cod-liver oil, and is said to be of equal efficacy as a therapeutic agent.”

According to the same source …

“There are three varieties of cod-liver oil met with in the market, namely, the pale, light brown, and dark brown. The different sensible properties of the oil depend upon the manner in which it is obtained from the livers, their state of freshness or otherwise, and the degree of exposure to the air in its preparation. The pale oil is prepared from fresh livers by the simplest possible process by which it can be separated from the cells of the livers; it is nearly devoid of color, odor, and flavor, having only a bland, fish-like, and, to most persons, not unpleasant taste. The darker oils are prepared from livers in a state of putrefaction, or with sufficient heat and pressure to decompose and extract the biliary matters; they have a ‘very ancient and fish-like smell,’ and an intensely disagreeable taste.”

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Nowadays, putrefied oil is bleached and deodorized so it can be hyped as “fermented,” and sold to a credulous public.

“Submerged culture fermentation” and “fermentation under conditions of high moisture content” sound much better than just plain “rotten.”
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