Cod Liver Oil for Dogs: Why it’s the Best Supplement

Nutrition Articles

An explainantion of the many benefits of cod liver oil for dogs and why it's the best supplement for your dog.

Welcome to the fourth and final post on my series on feeding dogs.  Last time I touched on cod liver oil for dogs as a great supplement, but today I thought I’d expand on it just a bit.

After reading the BARF Diet and researching the ideal diet for dogs, it’s funny just how many parallels there are between nutrition for dogs and nutrition for humans.  This is particularly true when it comes to healthy oils.

Consider these parallels:

  • The same refined vegetable oils that cause problems for humans also cause problems for dogs.
  • Just like humans, pets cannot manufacture the essential fatty acids (EFAs), omega-6s and omega-3s and must get them from their diet.
  • Just like humans, pets need a balance of omega-3s to omega-6s for good health.
  • Too many omega-6s promote inflammation in dogs just like in humans.
  • Processed pet food contains excessive levels of omega-6s, just like processed human foods.
  • Processed pet food is lacking in healthy omega-3s just as most supermarket food is for humans.
  • Factory-farmed meat is deficient in omega-3s for humans and pets.
  • When processed pet foods label “high in omega-3s” they’re using the same tricks that processed human foods use. 

Here’s a meme I created a while ago as a good example:

An explainantion of the many benefits of cod liver oil for dogs and why it's the best supplement for your dog.

That is a perfect example of an industrially-processed, nutrient-deficient “food” full of chemicals and trans-fats.  Add a little cheap fish oil or flaxseed oil to the chemical shit storm and now you can say “Omega-3” in huge print on the front of your product.  You see this sort of misleading nonsense everywhere these days, including dog food.

And let’s not forget that EFAs are very susceptible to heat and oxygen.  Modern manufacturing methods to extract EFAs from plant or animal sources usually damage the very fragile fatty acids.  As such, it’s just as unlikely your dog is getting any benefit from all those supposed omega-3s in your dried kibble formula as you are from eating Jif peanut butter.

This is why a good source of cod liver oil is a great supplement for your dog, especially if he/she is not eating a raw diet.

Dr. Ian Billinghurst, author of The BARF Diet says…

“Cod liver oil is the one daily (or weekly in the case of very small pets) supplement I recommend  above all else for the vast majority of pets.  My strongest advice is if you supplement with nothing else, you always supplement with fresh cod liver oil.  Perfect for both cats and dogs.”

As I said in my last blog, I give Lipton, the golden retriever I live with, about a half teaspoon of fermented cod liver oil a few times per week.

Why Fermented Cod Liver Oil For Dogs?

There are two huge benefits of fermented cod liver oil for dogs over unfermented versions.

The first is that the fermentation process preserves the nutrient content.

Green Pasture is the only company in the United States that uses this fermentation process which allows the oils to separate naturally from the livers.  This is the traditional method of extraction that was used before industrialization.

An explainantion of the many benefits of cod liver oil for dogs and why it's the best supplement for your dog.

Click here to find Green Pasture on Amazon.

All other companies use some form of refining which includes, heat, deodorization, winterization and bleaching to extract the oils and create the final product.  These processes can damage the delicate essential fatty acids and vitamins A and D, the very reason we take them.  Many companies add back vitamins A and D in synthetic form but it is highly questionable, and in my opinion unlikely, that our bodies absorb and utilize these synthetic forms.

This is why you won’t find fermented cod liver oil in Whole Foods or other large distributors.  Green Pasture can’t make it fast enough to supply those outlets.  The fermentation process takes TIME.  It takes 6 months to a year to ferment.  That is just not profitable and that is why no one does it anymore.

The second reason is that the fermentation process enhances the nutrient content, in particular, the amounts of naturally occurring fat-soluble vitamins A and D.  These nutrients are so vital to so many life-promoting processes in our body.  Dried kibble is deficient in these nutrients, no matter how good the quality.  And though many brands add them back in (just like with human foods and supplements), again, the extraction and processing methods compromise their nutritional value.

What About Excess Doses of A and D?

Many people are concerned about overdosing on A and D especially since fermented cod liver oil has higher amounts.

Dr. Billinhurst writes…

“…it is generally advised that you be cautious – because massively excessive doses may result in overdosing with vitamins A and D.  However, I wish to stress, in practice, it is quite difficult to produce vitamin A overdose.  Such a feat usually requires an inordinately high level of vitamin A containing substance, such as liver or cod liver oils or vitamin A capsules, is fed for weeks, months or even years!  However, erring on the side of caution, a safe level at which to supplement cod liver oil is to give enough cod liver oil to supply between 20 and 40IU of vitamin A per pound of pet (dog or cat) per day.”

Fermented cod liver oil contains approximately 10,000 IU of vitamin A per teaspoon.

So I give Lipton a half teaspoon.  That’s actually a little more than what Dr. Billinghurst suggests but I’m not really worried about it.  I only give it to her a few times per week and she’s not eating a raw diet.

Eric Letendre, a great dog trainer who I interviewed in part III, feeds his little 8-pound Maltese-poodle mix an eighth of a teaspoon a few times a week.

Note: If your dog is on a restricted diet or you have concerns over feeding your dog cod liver oil or any supplement, be sure to consult with your vet, ideally a holistic one as they will be more aware of the benefits of proper nutrition and supplementation.   The information provided here is for educational purposes only and is not a substitute for veterinary advice.

Where to Buy Fermented Cod Liver Oil

For sources of fermented cod liver oil for dogs, click here.

And to learn more about feeding your dog I recommend The Barf Diet by Dr. Ian Billingshurst

Read the Rest of My Series on Feeding Dogs

Well, that concludes my 4 part series on feeding dogs.  I hope you enjoyed it!

If you missed parts 1, 2, and 3 you can find them here:

Part I – Why You Should Stop Feeding Your Dog Dog Food

Part II – What to Do When You Can’t Feed Your Dog a Raw Diet

Part III – Why You Should Feed Your Dog Human Food


An explanation of the many benefits of cod liver oil for dogs and why it's the best supplement for your dog.

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About the Author

Craig Fear is the creator of Fearless Eating and the author of three books, The 30-Day Heartburn Solution, Fearless Broths and Soups and The Thai Soup Secret. After years helping clients with digestive issues, Craig decided to pursue writing full-time. He intends to write many more books on broths and soups from around the world! Click here to learn more about Craig.

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