***Please note that there have been some recent concerns about the below product. Please read more at this post, or click here for which kind to take. Do some reading and research, and decide for yourself what is best for your family. Thank you.
As my regular readers know, I'm always talking about how important it is to take cod liver oil. So as you would guess, it's not unusual for me to hear about all the reasons people are told they shouldn't take cod liver oil.
Don't believe me!
Even though, as I've said before, I don't want you to blindly believe what I say, but instead to let what you read here motivate you to do your own research, obviously, I still want to be careful about what I suggest to you. So if I hear something that conflicts with anything I recommend, do what I do – start researching like crazy and asking people who are much more knowledgeable about the topic than I am.
Let's get to the bottom of it
So to take care of any misinformation that you might be hearing, and in order to clear things up, today I'll share some recent email exchanges with you from my email box.
The first one is with Chris Masterjohn, who was nice enough to answer some questions for me; and following that, with Sally Fallon, who also helped to straighten things out. (In case you're not familiar with them, scroll to the bottom of this post for more information.)
Some of the following can get a little technical compared to the information I normally share on my blog, so if you would rather not read through all of it, be assured that after going over all of this many times, I'm still comfortable with continuing to recommend the amounts suggested at the WAPF site. (Except in a few circumstances, so you really should keep reading to find out more! You can also find out more here: common questions about cod liver oil where I talk about the possibility of vitamin A or vitamin D toxicity – especially look down in the related posts at the bottom.) However, if you choose not to do further reading and research on your own, please be sure to take another look at the disclaimer at the very bottom of this post!
Recently a reader struggling with depression was told to only take enough cod liver oil to reach 4000 IU/day of vitamin A because it can cause liver damage. (I had suggested she take at least the amount recommended by the WAPF, which is the dose that equals 10,000 IU/day of vitamin A.)
I found this online at Dr. Andrew Weil's site: “The Upper Limit of vitamin A set by the Food and Nutrition Board of the National Academy of Sciences is 10,000 IU per day. Although it is an essential nutrient, an excessive, chronic intake of the form of vitamin A from animal sources (including cod liver oil) can be toxic, leading to hair loss, confusion, liver damage, and – more recently discovered – bone loss.”
Could you comment on this?
Vitamin A can be toxic to the liver if intake exceeds the liver's storage capacity. This is evident on blood tests if you test for serum retinol and serum retinyl esters both. If the latter exceeds 10% of the sum of the two measurements, this is a sign that the liver's storage capacity has been overwhelmed.
Vitamin A toxicity generally takes much more than 10,000 IU/day. Protein and zinc are necessary for vitamin A utilization, so the dose that would lead to toxicity would be much lower on a diet deficient in protein and zinc — i.e., deficient in animal foods. Vitamin D protects against vitamin A toxicity and also increases the utilization of vitamin A, making it even less likely you'd overwhelm your liver's capacity.
Since cod liver oil — good cod liver oil, that is, like the brands recommended by WAPF — contains vitamin D, it's incredibly unlikely that anyone would get vitamin A toxicity from 10,000 IU/day vitamin A.
Hope that helps,
I bugged Chris one more time:
Thanks for your help! One last question that I'm concerned about: someone recently stopped taking cod liver oil when their doctor said it can cause bleeding – that it can thin the blood. Is this something I should be warning my readers about?
There is EPA in cod liver oil, a fatty acid that can compete with arachidonic acid, an important fatty acid necessary for blood clotting. In my PUFA Report (http://www.cholesterol-and-health.com/PUFA-Special-Report.html), I argue that EPA is not an essential fatty acid, but that if your diet is low in linoleic acid from vegetables and rich in zinc and B6, you'll convert small amounts of EPA to DHA, which is essential.
Either way, the amount of EPA in cod liver oil is small, and blood thinning is mostly a concern with large amounts, like when people take “fish oil” in large amounts for its anti-inflammatory properties.
You can minimize the EPA you get by using high-vitamin cod liver oil, so you get the most vitamins for the least EPA. You can get over 10,000 IU vitamin A from just one teaspoon of high-vitamin cod liver oil, which provides only a small amount of EPA that will probably not cause blood thinning in most people.
By the way, Chris has a great new blog called, The Daily Lipid.
(Note: the above information was used here with permission from Chris Masterjohn.)
Recently, I also emailed Sally Fallon with my concerns, and she replied with a new cod liver oil update.
However, if I posted all of it here, this would be way too long. So click here for the INFORMATION UPDATE ON COD LIVER OIL from Sally Fallon.
- My favorite cookbook: “Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and the Diet Dictocrats” by Sally Fallon
- Another book by Sally Fallon along with Mary Enig – I love this one too: Eat Fat, Lose Fat: The Healthy Alternative to Trans Fats
Chris Masterjohn's Bio from the Weston A. Price Foundation:
Chris Masterjohn is the author of several Wise Traditions articles and the creator and maintainer of Cholesterol-And-Health.Com, a website dedicated to extolling the virtues of cholesterol and cholesterol-rich foods. He has authored two items accepted for publication in peer-reviewed journals: a letter in an upcoming issue of the Journal of the American College of Cardiology criticizing the conclusions of a recent study on saturated fat and a full-length feature in an upcoming issue of Medical Hypotheses proposing a molecular mechanism of vitamin D toxicity. Masterjohn holds a Bachelor's degree in History and is preparing to pursue a PhD in Molecular and Cellular Biology. He is also a Weston A. Price Foundation Local Chapter Leader in West Brookfield, Massachusetts.
Sally Fallon is the author of Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and the Diet Dictocrats (with Mary G. Enig, PhD), a well-researched, thought-provoking guide to traditional foods with a startling message: Animal fats and cholesterol are not villains but vital factors in the diet, necessary for normal growth, proper function of the brain and nervous system, protection from disease and optimum energy levels. She joined forces with Enig again to write Eat Fat, Lose Fat, and has authored numerous articles on the subject of diet and health. The President of the Weston A. Price Foundation and founder of A Campaign for Real Milk, Sally is also a journalist, chef, nutrition researcher, homemaker, and community activist. Her four healthy children were raised on whole foods including butter, cream, eggs and meat.