Faulty Interpretation of Cod Liver Oil Data

by elam
(lancaster, Pa.)

Your interpretation of folks getting liver damage from cod liver oil (referring to the page Cod Liver Oil Information) is misleading and actually wrong. the study mentions high levels of vitamin A being taken much more than one can get from a tablespoon of cod liver oil...

You did some really poor math here and set things up to prove a false point. The study you gave a link to, says that the smallest daily dose leading to the liver damage was 25,000 IU of Vitamin A (During 6 Years!).

There are 3000 IU of Vitamin A along with 1200 IU of vitamin D in a tablespoon of cod liver oil so one would have to ingest over 8 tablespoons of it daily to reach the smallest daily dose that lead to the liver damage in six years!

And you say: Furthermore, some studies believe that even moderate use of these preformed retinols may be contributing to liver damage. Some studies believe and may are weak words for your argument.

So, present a better argument against cod liver oil than the poor hysterical one you put together here.

This makes me wonder about the rest of your data...though I do agree that more Vitamin D is necessary but having it come from a whole food is preferable in the long and short run.

Comments for Faulty Interpretation of Cod Liver Oil Data

Click here to add your own comments

It's too bad that you don't leave your info...
by: Kerri Knox, RN- The Immune Queen!

Hi Elam,

I'm always up for a challenge of what I say, but I find it interesting that those who ask for my help leave their email so that they can get my answer, but that those who criticize me, like you, don't leave their email- and therefore have no possible way to get my answer back and respond.

But, I'll answer anyway even though will not see this answer because you attacked me
and ran off.

So, first of all, this is an informational website and not a PhD dissertation. I use more references to actual peer reviewed studies than almost any website you will find out there, so if I make a reference to 'some researchers', I have very often included a link for you to go do your own research if you don't believe me.

You say that the dose required for liver damage is not a realistic amount of cod liver oil -yet the peer reviewed study that I quoted stated that the Vitamin A doses were 'Therapeutic' and at only 25,000 IU's per day, that is about the equivalent of 2 multivitamin tablets per day! That is NOT particularly high at all.

And that same study cited 41 cases of liver toxicity from Vitamin A Supplements!! And that is only in ONE STUDY!! THEIR conclusion, not mine, is

"The data also indicate that prolonged and continuous consumption of doses in the low "therapeutic" range can result in life-threatening liver damage."

If you want to argue your point about data interpretation, take it up with the 5 researchers in the study- not me!

Then This Study brings up the point that Vitamin A becomes even MORE toxic in those who drink alcohol- and a LOT of people out there drink alcohol.

You also say there is "3000 IU of Vitamin A along with 1200 IU of vitamin D in a tablespoon of cod liver oil". I'm looking at several different formulations right here and they have:

Nordic Naturals: One TEASPOON has 3000 IU's of Vitamin A and 20 IU's of Vitamin D

Childlife Essentials: One TEASPOON has 2000 IU's of Vitamin A and 40 IU's of Vitamin D

Genestra: One TEASPOON has 2667 IU's of Vitamin A and 300 IU's of Vitamin D

Carlson: One TEASPOON has 2500 IU's of Vitamin A and 500 IU's of Vitamin D

Pure Encapsulations: One TEASPOON has 1750 IU's of Vitamin A to 150 IU's of Vitamin D

So, you say that getting Vitamin D in foods is better in the long run. What foods would those BE!? Researchers are recommending between 3800 to 5000 IU's of Vitamin D daily and from my Vitamin D Foods page, you can see that's a heck of a lot of salmon!



cod liver oil stuff continued...
by: Kerri Knox, RN- The Immune Queen!

More About Vitamin D

...if you were to get that from Cod Liver Oil, lets take the Cod liver oil with the BEST Vitamin A to Vitamin D ratio. In order to get 3800 IU's of Vitamin D. That would mean that you would be getting 19,000 IU's of preformed retinols in order to get the minimum amount of Vitamin D recommended on the Vitamin D Requirements page.

Using the cod liver oil from above with the WORST ratio, you would need to take 570,000 IU's of Vitamin A to get 3800 IU's of Vitamin D per day.

So, my point is that Cod Liver Oil is NOT a good source of Vitamin D and that you would need to take a potentially toxic dose of Vitamin A in order to get the proper amount of Vitamin D that you need. While the study only identified 25,000 IU's per day as toxic 19,000 in the BEST cod liver oil supplement (Carlson) from above is pretty close and 570,000 IU's is way over that. And since I plan on getting Vitamin D in the range of approximately 3800 to 5000 IU's per day for the rest of my life, I believe the risks of taking cod liver oil outweigh the benefits and simply taking a plain old Vitamin D3 Supplement is far safer.

If YOU want to take 19,000 IU's of preformed retinols every day just to get enough Vitamin D to meet your needs, then you certainly can do that, but I'll choose not to and I'll continue to recommend that my readers do not either.

Kerri Knox RN Immune Health Queen

Kerri Knox, RN- The Immune Health Queen
Functional Medicine Practitioner
Easy Immune Health.com

Click here to add your own comments

Return to Cod Liver Oil Information.

Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.


Search this Site
Custom Search


Vitamin D Fact Sheet
Free Vitamin D Fact Sheet by Getting
My Newsletter