Is Cod Liver Oil Good for You?

Is Cod Liver Oil Good for You?
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Even distilled cod liver oil supplements may have toxic levels of vitamin A.

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Cod liver oil that has been distilled to remove any industrial toxins and heavy metals. Still harmful, harmless, or healthy?

Harmful, due to the toxic levels of vitamin A. In fact, so much it could damage our own liver. So, not good for the cod’s liver, or ours.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by veganmontreal.

Please consider volunteering to help out on the site.

Cod liver oil that has been distilled to remove any industrial toxins and heavy metals. Still harmful, harmless, or healthy?

Harmful, due to the toxic levels of vitamin A. In fact, so much it could damage our own liver. So, not good for the cod’s liver, or ours.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by veganmontreal.

Please consider volunteering to help out on the site.

Doctor's Note

Also check out: Is Fish Oil Just Snake Oil?

And check out my other “HHH” videos (Harmful, Harmless, or Helpful?)

For further context, see my associated blog post: Soy milk: shake it up!

If you haven’t yet, you can subscribe to my videos for free by clicking here.

39 responses to “Is Cod Liver Oil Good for You?

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    1. Dr. Greger,

      First of all, I’d like to thank you for your website and life’s work. I am an integrative medicine physician who does have time to speak about nutrition with my patients. You have completely changed the way I practice medicine and hope to reach a lot of people with your powerful information. it has already made a huge impact on my health, and I’m expecting the same for my family and patients.

      Question: Is the reason you don’t recommend Fish Oil is because of its potential contamination or because it doesn’t help regardless of how “clean” it is? My personal literature search on the topic left me confused and pretty sure no one knows whether or not it’s helpful or not. In context with all of the other information you provide on your website, my gut tells me that adding an animal fat in supplement form would not be a good thing. However, I would like to hear a bit more of your knowledge on the subject. Thank you.

      1. Hi Joe Mazzei – That is wonderful news and thank you for all of your support and positive feedback with NutritionFacts.org!

        Dr. Greger has several videos/articles that discuss the downsides to fish oil supplementation that I’ve included below. These include the risk of potential contamination, increased risk of prostate cancer, and higher risk of cardiac death. Instead of fish oil, Dr. Greger recommends 250 mg/day of algae oil as a safer supplement option.

        -https://nutritionfacts.org/2018/02/20/the-risks-of-fish-oil-supplements/
        -https://nutritionfacts.org/video/is-fish-oil-just-snake-oil/
        -https://nutritionfacts.org/video/should-we-take-epa-and-dha-omega-3-for-our-heart/
        -https://nutritionfacts.org/video/should-vegans-take-dha-to-preserve-brain-function/

        I hope this helps give further insight!
        -Janelle RD – Registered Dietitian & NutritionFacts.org Health Support Volunteer

        1. Thank you so much Janelle.

          Joe Mazzei, D.O.

          jmazzeido@bodylogicmd.com

          BodyLogicMD of Phoenix-Chandler 3120 N.Arizona Ave. Suite 103 Chandler, AZ 85225 P 602 536-0699 | F 877 334-2580 Toll-Free 877 341-7326

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          For assistance please call the office and select: Option 1 to become a patient Option 2 to order lab work Option 3 to check status of lab results or schedule / reschedule appt Option 4 to speak directly with the physician’s office Option 5 for the AutoOrders Department – Pharmacy / Supplements

          Confidentiality Note: This transmission is intended only for the addressees and contains privileged and/or confidential information of BodyLogicMD and its affiliates. If you are not the intended recipient, please destroy any copies.

  1. I’ve been using Arctic Cod Liver Oil from Nordic Naturals for years. I’ve also been giving it to my 7 year old son for years. I’m deeply concerned about the possibility of liver damage due to high levels of A. Are you recommending that we no longer use cod liver or fish oil supplements?

    1. According to the bottle of the Nordic Cod Liver Oil, there is only 650 IU of vitamin A per serving (about 13% of Daily Value). This is no where near toxic levels. I’m assuming that most other common cod liver oils off the shelves are no where near toxic levels either.

  2. Where is the answer to the question ” what is considered to be a toxic level of Vitamin A? I would like to know the answer too.

    1. “Because vitamin A is fat soluble, the body stores excess amounts,
      primarily in the liver, and these levels can accumulate. Although excess preformed vitamin A can have significant toxicity (known as hypervitaminosis A), large amounts of beta-carotene and other provitamin A carotenoids are not associated with major adverse effects”

      Upper limits are capped at 3,000 IU’s so consuming 10,000 IU’s of preformed vitamin A is indeed toxic.

      http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

      More information on fish oil can be found here. The science indeed shows ill effects.

      http://nutritionfacts.org/topics/fish-oil/

      1. 10,000 iu is the upper safe level for vit A !! people regularly consume 20 – 50000 iu without issue. Many people can’t convert betacarotene to Vit A & thought to cause cancer in smokers for this reason. Many believe since abandoning organ meats we don’t get enough & rdi should be higher.
        It is now known that we don’t convert beta carotene 1 for 1 either.

        1. The safe upper limit is 3,000 not 10,000. People do not regularly consume mass quantities of preformed vitamin A as this would lead to toxicity. Your statements regarding beta carotene are untrue and unsupported. Please share evidence to back your claims.

          1. 3000 is the RDI !!! 10000 is the upper safe level.
            Wardlaws perspectives in nutrition , upteen govt sources & the cancer council. Do a search on google scholar.

  3. if distilled=concentrated then perhaps, but distilled=purified to my knowledge, the levels of vit A in fish oil are not toxic. people can consume 10,000 iu with no toxicity.there is a difference between helpful advice and scaremongering- fish oil is the most important supplement today to combat our diets.

    1. “Because vitamin A is fat soluble, the body stores excess amounts,
      primarily in the liver, and these levels can accumulate. Although excess preformed vitamin A can have significant toxicity (known as hypervitaminosis A), large amounts of beta-carotene and other provitamin A carotenoids are not associated with major adverse effects”

      Upper limits are capped at 3,000 IU’s so consuming 10,000 IU’s of preformed vitamin A is indeed toxic.

      http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

      More information on fish oil can be found here. The science indeed shows ill effects.

      http://nutritionfacts.org/topics/fish-oil/

        1. http://www.cancer.gov/cancertopics/pdq/prevention/lung/HealthProfessional/page1#Section_206
          Interventions Associated With an Increased Risk of Lung Cancer

          Beta-carotene supplementation in current smokers

          Based on solid evidence, high-intensity smokers who take pharmacologic doses of beta-carotene have an increased lung cancer incidence and mortality that is associated with taking the supplement.

          Magnitude of Effect: Increased risk, small magnitude.

          Study Design: Two randomized controlled trials with consistent results.Internal Validity: Good.Consistency: Good.External Validity: Good.

          1. Beta carotene supplements have been well established to pose risk for all individuals. The problem is when you isolate a nutrient and try to supplement it. The caratonoids collectively in greens and orange, yellow vegetables do not pose a health risk and will decrease risk of cancer significantly.
            http://nutritionfacts.org/video/some-dietary-supplements-may-be-more-than-a-waste-of-money/
            http://nutritionfacts.org/video/antioxidant-vitamin-supplements/
            http://nutritionfacts.org/video/produce-not-pills-to-increase-physical-attractiveness/

  4. If fish oil has no benefit, then why did my triglercerides go way down? When I stopped taking the fish oil, it came way back up again! I started to take fish oil again….my triglycerides went back down! WHY?????

    1. Hi Rose. I am not sure. I am glad they went down though, most importantly! This video is just mentioning cod liver oil and toxic levels of vitamin A.

      1. Michael doesn’t talk at what levels its toxic. Everything is toxic at some level. There are studies that show health benefits.
        In general I find his videos most informative.

        When he creates a video like this I begin to question all his work. Which I hope is not warranted.

        J Am Coll Nutr. 2010 Dec;29(6):559-62.

        Cod liver oil, young children, and upper respiratory tract infections.

        Linday LA1.

        Author information

        Abstract

        Cod
        liver oil contains long-chain omega-3 fatty acids, as well as vitamins D
        and A. It was a traditional source of vitamin D in the United States
        and was used to prevent and treat rickets. In our clinical research, we
        used liquid cod liver oil of adequate purity and acceptable taste for
        infants and young children, as well as a children’s multivitamin/mineral
        supplement with selenium and other trace metals. In a
        cluster-randomized study of pediatric visits for upper respiratory
        illness during the winter and early spring, these nutritional
        supplements decreased mean visits/subject/month by 36%-58%. Cod liver
        oil is culturally valued and has been used as a folk remedy by many
        low-income minorities in the United States. Nutritional supplements
        cannot be purchased with SNAP benefits (formerly called food stamps).
        Inclusion of cod liver oil in state Medicaid formularies would make it
        available to low-income children, whose families may not be able to pay
        for it out-of-pocket.

  5. So I’m new to this site, but I’ve been an avid learner of the principles taught by the Weston A. Price Foundation. And I’m open to learn, but I’d like to see a response to this article: https://www.westonaprice.org/health-topics/cod-liver-oil/cod-liver-oil-basics-and-recommendations/#clarify
    I’ve followed their guidelines, even during my pregnancy, and it properly prepared cod liver oil has given me and my child really positive results.
    See also https://www.westonaprice.org/health-topics/abcs-of-nutrition/vitamin-a-saga/
    Not trying to argue here; I just really want clear answers.

  6. Hello Chelsea- I’ve read the article, and it states the Foundations belief that vitamin A toxicity is exaggerated and that taking high amounts of vitamin A is safe as along as it is sourced from whole foods.

    Unfortunately, they do not provide peer reviewed, published science to back that claim. I’ve performed a search of peer reviewed, published science on retinol (vitamin A) and the scientific community agrees that vitamin A, above minimal nutritional needs, is proven to be harmful in many ways, particularly to the nervous system. It is not known precisely why vitamin A is toxic, but it has been demonstrated over many years and published in the literature.

    There is no scientific, published proof that high levels of vitamin A (above those nutritionally required) as found in cod oil, vitamin A supplements, or any other form is safe, and they are shown to be toxic.

    Here is one recent published review of this topic: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015005040677&lng=en&nrm=iso&tlng=en

    Best, Dr Anderson, volunteer

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