Cod Liver Oil Topics

Once a standard supplement in traditional European societies, cod liver oil provides fat-soluble vitamins A and D, which Dr. Price found present in the diet of “primitives” in amounts ten times higher than the typical American diet of his day. Cod liver oil supplements are a must for women and their male partners, to be taken for several months before conception, and for women during pregnancy. Growing children will also benefit greatly from a small daily dose.

Dr. Price always gave cod liver oil with high-vitamin butter oil, extracted by a slow centrifuge from good quality spring or fall butter. He found that cod liver oil on its own was relatively ineffective but combined with butter oil produced excellent results. We now know that butter oil is an excellent source of vitamin K, which is needed to balance vitamins A and D in cod liver oil.  Other good sources of vitamin K in western diets are aged cheeses and the fat and livers of ducks and geese; other sources include butter and egg yolks. Without the balance of vitamin K, cod liver oil could lead to heart troubles, bone problems, tooth decay and gum disease.

Likewise the omega-3 fatty acids in cod liver oil require balance by omega-6 arachidonic acid (AA), found in butter, meat fats, organ meats and egg yolks.  Without the balance of AA from animal fats, cod liver oil could contribute to skin problems and digestive problems.

It’s all about balance!  Be sure that when you take cod liver oil you also include sources of AA and vitamin K in your diet.

Read this introduction in: French

Cod Liver Oil Basics and Recommendations

Fermented Cod Liver Oil Available from Chapter Leaders and Members

The Yin and Yang of Cod Liver Oil
December 2008 Update on Cod Liver Oil
December 2008 Update 2 on Cod Liver Oil

A Response to Dr. Joe Mercola on Cod Liver Oil
The Cod Liver Oil Debate

Cod Liver Oil: Setting the Record Straight


We continue to receive questions about our recommendations for cod liver oil and specifically for fermented cod liver oil.  We have addressed these concerns very conscientiously, both in our journal and in emails to members on this subject.  You can find these reports and articles on our website at and specifically in the article

A few individuals have claimed that fermented cod liver oil is rancid, contains low levels of vitamin D and contains trans fatty acids.

The Weston A. Price Foundation tested all three brands of cod liver oil in the Shopping Guide Best category for rancidity using magnetic resonance testing, the most modern and accurate type of testing available.  The fermented cod liver oil proved to be the most stable, showing no signs of rancidity whatsoever.  In addition, the high levels of omega-3 fatty acids in fermented cod liver oil indicate that none of these fragile molecules have broken down.

We also tested for vitamin D. One lab found only low or non-existent levels in the two brands we tested—the fermented cod liver oil and a second brand of unheated cod liver oil; however a different lab found very high levels of vitamin D in both of these brands. These results indicate that the type of natural vitamin D in cod liver oil is not the same as the type of vitamin D that is added to highly refined cod liver oil and to other foods. (The first lab only looked for added vitamin D.) Please see a discussion of vitamin D in cod liver oil at

Finally, on the issue of trans fatty acids in cod liver oil, it turns out that all fish liver and fish oils contain low levels of natural trans fatty acids.  These come from fungus that the fish eat.  It should not surprise us that fish oils contain natural trans fats, as animal fats do also.  The presence of trans fats in cod liver oil is not evidence that these oils have been adulterated with vegetable oils, as some have claimed, but is actually evidence that the oils are natural.

In our Shopping Guide, we list three brands of cod liver oil in the Best category. These products have not been heated and retain all of their natural vitamins. The brands listed in the Good category have been processed with heat (a process called molecular distillation) and have added synthetic vitamins in the right proportions.

Concerns About Cod Liver Oil
Questions and Answers About Fermented Cod Liver Oil
Chris Masterjohn Blog on Fermented Cod Liver Oil
Vitamin D in Cod Liver Oil
Constant Controversy: Cod Liver Oil and Our Changing Food Paradigms
Scientific Analysis of Fermented Cod Liver Oil conducted by Dr. Jacob Friest, PhD
Hook, Line, and Thinker: Adding Context to Kaayla Daniels’ Report on Fermented Cod Liver Oil
Report on Cod Liver Oil
Powerpoint on Cod Liver Oil Issues, presented by Sally Fallon Morell, November 14, 2015
The Fat Soluble Activators (PDF 2.7MB)


    © 2015 The Weston A. Price Foundation for Wise Traditions in Food, Farming, and the Healing Arts.