FAQ-Cod Liver Oil

  • Carlson’s
  • How Much
  • Orange Color
  • Belching
  • Sufficient calcium with CLO
  • Cod Liver Oil and osteoporosis
  • CLO and sun exposure

Cod Liver Oil (CLO)

For a summary of our position on cod liver oil click here for the Cod Liver Oil section of the website.

Q. Is Carslon’s a good brand of cod liver oil?

A. We no longer recommend Carlson’s because the vitamin A content is too low. See our brand recommendations here.

Q. How much cod liver oil should I take?

A. We recommend the equivalent of 10,000 IUs of vitamin A per day for general health of adults and half that for children. A high vitamin cod liver oil will have that much vitamin A in 1 teaspoon.

Q. Should cod liver oil have an orange color?

A. Vitamin A is colorless (carotenes are orange). So there is no need for cod liver oil to have an orange color. In the past, before modern filtering techniques, cod liver oil was a dark yellow or brown color, which was from the livers.

Q. Cod liver oil makes me belch, what do you suggest?

A. If someone is belching from cod liver oil, try giving a smaller dose, more often, usually just right before a meal.

Q: In Krispin Sullivan’s article on vitamin D, it mentions to be sure that you have sufficient calcium intake when you are supplementing your diet with cod liver oil.  The article mentions the amount of 1200 – 2400 mg of calcium a day.  Can you tell me how many mg of calcium are in 8 ounces of raw milk or 8 ounces of raw milk yogurt?

A: About 600 mg in 16 ounces of raw milk.  About 200 mg in one ounce of cheese.

Q: I know that fish oil is bad for us especially because there is too much omega-3 derivatives EPA and DHA. And this disrupts the balance between omega-3 and omega-6, which weakens the immune system right? You clearly mention on your website that you don’t recommend fish oil. But cod liver oil is a fish oil right? So the same reasoning applies to cod liver oil. It will disrupt the balance between the omega-3 and 6, which is bad. In this case, is it better to take the cod liver oil with some omega-6 rich oils like safflower or sunflower oils? Dr. Mercola, and others, recommends krill oil, what do you think of that?

A: We recommend cod liver oil to get adequate A and D.  Using the high-vitamin cod liver oil or even the regular dose cod liver oil, you can get adequate A and D without overdosing on either omega-6 or omega-3.  Also, the vitamin A protects the polyunsaturates from oxidation.  Be sure to use only the brands of cod liver oil that we recommend.

The manufacturers of krill oil do not reveal how much A and D is in their oil, so I have to assume it is not much.  So there is no reason to take krill oil.

Q: I’m looking for information that backs up including fish and fish oils in our diets, but also something that takes into consideration the mercury and heavy metals issue. Basically, vegetarian groups and groups like PETA use the claim that the heavy metals and PCBs in fish preclude us eating them.

A: Fish does contain mercury but if you have good intestinal flora, you are completely protected against absorbing the mercury–but you are not protected from absorption through the mouth (as in mercury fillings) or the skin.  Also, mercury is store in the protein not in the fats in the fish.

There is a good article on our website on dioxins and also, do read the whole section on cod liver oil. Vitamin A from cod liver oil is our best protection against dioxins, which are found in many, many foods, not just animal foods.

Q: Does Cod Liver Oil have a negative effect on Osteoporosis?

A: from Chris Masterjohn: There is no evidence that Cod Liver Oil worsens Osteoporosis risk and the scant evidence that exists suggests it may be beneficial. Here is a very brief description of the evidence that should be beneficial.


Also I have a very lengthy review of the evidence on vitamin A in general:


In brief, vitamin A can probably aggravate the risk of Osteoporosis in someone who is deficient in vitamin D, but since most brands of Cod Liver Oil contain both, it is most likely protective. Indeed the only epidemiological study that mentioned Cod Liver Oil as a major vitamin A source, found that those with the highest vitamin A levels had the lowest risk of fracture.

Q: My husband works on an organic farm in Austin, TX – as you can imagine, he is exposed to the sun. He has been taking CLO and I am worried he maybe getting too much Vitamin D. I contacted Green Pastures and they responded that it was different Vitamin D.
How much CLO would you suggest he be taking, if any?

A: (from Chris Masterjohn) I doubt he will overdose on vitamin D because CLO contains much more vitamin A than D.  While I believe it is important to also get plenty of vitamin K from a diversity of sources including leafy greens, fermented foods, and grass-fed animal foods, animal experiments suggest that having a hefty amount of vitamin A in the diet and virtually eliminate any risk of vitamin D toxicity.

That said, I think we should also be wary about overdosing on CLO because of the omega-3 fatty acids and because, traditionally, there were limits to the perceived safety.  Price, for example, used 3/4 of a teaspoon of high-vitamin cod liver oil and did not consider it advisable to use more than a teaspoon for extended periods of time. John Hughes Bennett noted that peasants would often use it in large quantities of 1-2 pints, but only for a week at most.  Medical men, he said, would give 2-4 tbsp/day to adults and 1-3 tsp/day to children, but he noted that if this was continued for six or seven months it would invariably result in toxicity.

I think these problems are partly from oxidation products and modern CLO might be somewhat safer.  However, I think that overdose on omega-3 fatty acids is a genuine concern, and I also think we should stick within traditional precedent.

Thus, I would say 3/4 tsp/day should be considered an absolute maximum for long-term use.  If you are using it for some therapeutic reason in the short-term, you could use more, perhaps much more, but should listen to your body and only use it if it seems to be helping.

Tim Boyd was born and raised in Ohio, graduated from Case Western Reserve University with a degree in computer engineering, and worked in the defense industry in Northern Virginia for over 20 years. During that time, a slight case of arthritis led him to discover that nutrition makes a difference and nutrition became a serious hobby. After a pleasant and satisfying run in the electronics field, he decided he wanted to do something more important. He is now arthritis free and enjoying his dream job working for the Weston A. Price Foundation.

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