I recently recommended cod liver oil to my email list, and one of my subscribers replied with concerns about cod liver oil being toxic and unsustainable, which are valid concerns. So I attempt to address those concerns in this post. This post also discusses beef liver, when it might be advisable to emphasize vitamin A over vitamin D or vitamin D over vitamin A, and relationships between vitamins D, A, K, E and zinc, copper, and iron.
Are Liver-Based Foods Inherently Toxic These Days?
Because the liver of an organism processes toxins, many people assume that liver is toxic by accumulating of toxins. And this certainly can be the case if the animal is exposed to a high level of toxins and/or does not have a well-functioning liver.
But the fat in the flesh of such an animal could be even more toxic because toxins are stored in fat, yet fat cells are not designed to expel toxins like the liver is designed to do.
So I would not avoid liver due to the fact that it processes toxins. That is actually one of the reasons I would eat it. Liver is packed with nutrients in part because it is toxin-expelling and metabolic powerhouse in a healthy animal.
But I would not eat the flesh, the liver, oil from a liver, or any other part of an animal from a highly toxic environment, or that is fed highly toxic food (e.g. conventional meats).
However, we must realize that manmade toxins have spread over the entire planet. So there no way to avoid toxins entirely. Even organic plant foods have toxins in them from pesticide drift and other sources.
Yet there are animal foods from many places on the planet that are low enough in toxins for us to gain more benefit than harm by eating them. For example, healthy pastures that are not sprayed with herbicides can produce high-quality livestock with low toxic burden.
And even certain ocean environments can still provide foods that provide more benefit than harm from their toxic contents. So the oil from a cod's liver harvested from one of these environments should provide more benefit than harm and is also probably lower in toxins than the flesh of the fish.
But is Cod Liver Oil Sustainable?
Whether cod liver oil can be considered a sustainable food depends on the fishery it is harvested from and how it is harvested.
An organization called the Marine Stewardship Council (MSC) has a well-developed system for monitoring and certifying fisheries, fishing methods, and the chain of custody of fishery products, such as the cod liver oil (Green Pasture) I recommended last week.
Some stocks of cod in the Atlantic are closed to fishing because they were fished unsustainably and still have not recovered. Other cod fisheries are doing well and are being harvested sustainably, according to the MSC.
But how does the MSC determine that a fishery is being sustainably harvested, and what methods are considered sustainable?
Although there is some information on the MSC website about this, I have not yet found highly detailed information to answer these questions and am waiting for an answer to an email I sent to the MSC.
Even if their answers are not totally satisfactory, there is an argument for consuming the most sustainable products available because it sends a demand signal for the most sustainable ones over the less sustainable ones.
Why Would I Even Want to Consume Cod Liver Oil?
The main reason to consume cod liver oil is the high concentration of preformed vitamin A. This is valuable for people that have a slow version of the enzyme that converts beta carotene to retinol (vitamin A).
And high doses of vitamin A are very useful in situations requiring a stronger immune response. Improving immune response is not all about herbs. You have to have the vitamins and minerals that are actually involved in immune system processes that can respond to herbs.
And high doses of vitamin A have been used successfully to treat tuberculosis and viral infections, including the one that has preoccupied the world for the past three years. Therapeutic dosing of vitamin A is a very potent strategy in various situations.
Is There a More Reliably Sustainable Option?
Despite the virtues of cod liver oil, liver from grass fed beef might be a more sustainable source of high quantities of vitamin A than anything from the ocean. But I am not aware of any research using beef liver to treat illness.
Some people have a very strong aversion to the taste of liver. I used to experience nausea in response to beef liver until I worked at being able to tolerate it. Now I actually enjoy it, so it's possible to totally reverse an aversion to liver. And liver probably has a more noticeable beneficial impact on how I feel than any other food, most likely due to the long list of nutrients in beef liver. More on that later.
But again, all or most of the research on mega-dosing natural vitamin A has been done with cod liver oil, not beef liver. So it's possible that there are other factors in cod liver oil that contributed to the therapeutic benefits. Perhaps beef liver would not have the same effect.
The bottom line is that cod liver oils is an amazing food / supplement, and sourced well it is probably not be any more toxic than the rest of the fish. But the true sustainability of it could use more documentation.
By the way, although some studies using synthetic vitamin A have shown benefit, others demonstrate it to be toxic. So it appears to be a mixed bag. It could be an acceptable option for vegans, but my preference is for food-based vitamin A, and no plants have vitamin A. Many plant foods contain "provitamin A", which is beta carotene, but some people do not efficiently convert beta carotene to vitamin A.
Balancing Vitamins A and D
Whenever vitamin A intake is increased vitamin D intake should also be increased, and vice versa. The potential for toxicity from high doses of vitamin A or vitamin D is due to an imbalanced ratio of vitamin A to vitamin D.
As long as there is enough of both vitamins in the body, the ratio between the two is highly flexible and depends on the needs of the situation. In fact, there may be situations when it would make sense to emphasize vitamin A over vitamin D, or vitamin D over vitamin A.
Differing Therapeutic Ratios of Vitamins A and D
Vitamin A seems to ramp up an acute immune response,
In contrast, vitamin D seems to support immunity while dampening an overactive immune response like a cytokine storm.
So when autoimmunity or other immune system hyperactivity is present, I believe that the ratio of vitamin A to vitamin D should probably be lower than what is the research usually indicates is generally optimal. General research on ratios suggests that the ratio should be anywhere between 2:1 to 8:1 in favor of vitamin A.
But with autoimmunity or other immune system hyperactivity, the emphasis should probably shift toward vitamin D, perhaps targeting a radio fo 1:1 or even less than 1:1, which means using more vitamin D than vitamin A.
On the other hand, when there is an infection that requires more immune system activity, then an emphasis on vitamin A is probably necessary to ramp up a more aggressive immune response.
Additional Benefits of Whole Liver and Cod Liver Oil
Another reason to potentially use liver instead cod liver oil for day-to-day use (but possibly not when wanting to fight an acute infection), is that in addition to vitamin A, whole liver (e.g. beef liver) contains many other vitality-promoting nutrients. Liver is a great source of B vitamins, copper, and other minerals and nutrients. But perhaps more importantly, liver contains short peptides called "bioregulators" that help regenerate the liver of the animal or human eating the liver.
Everybody I know that has ever eaten liver noticed a lift in vitality, even people that don't particularly like liver. I think that well-sourced liver is one of the healthiest foods that anyone can eat.
Cod liver oil is also a broadly nourishing food. In addition to vitamin A, it contains vitamin D (usually 1/10th the amount of vitamin A), omega-3 fatty acids, and proresolving mediators (reduce inflammation).
Liver and cod liver oil are foods that I recommend to most of my clients in the Bio-Individual Blueprint program as part of general nutrition.
Do Not Forget About Vitamin K2 , Vitamin E, and Zinc!
By the way, no conversation about vitamins A and D would be complete without mentioning vitamins K2 and E. As you probably know, vitamin K2 is necessary for completing the activation of vitamin D dependent proteins that govern the distribution of calcium in the body. Without K2, calcium might be deposited in soft tissues rather than hard tissues, and this can become life-threatening if the soft tissues being calcified are arteries.
Vitamin E is involved in processing vitamin K2, so it's important to get both and not neglect the other. In fact, Dave Asprey, the original biohacker, has coined a term for the combination of these vitamins: "DAKE". He refers to them as "vitamin DAKE" in order to communicate that these vitamins should always be considered together.
It's also important to realize that vitamin A is activated by zinc, so if you're deficient in zinc, your vitamin A might not work very well. And without activation by zinc, high doses of vitamin A are more likely to become toxic.
The Copper Connection
And when we speak of zinc, we must also include copper because zinc reduces absorption of copper, so supplementing with a lot of zinc can cause copper deficiency, which can develop quickly.
Copper is carried around the body by a protein called ceruloplasmin, which requires vitamin A and healthy adrenal glands for its production. So if there is not enough vitamin A and/or wiped out adrenal glands, and if ceruloplasmin levels drop below normal, copper can become unbound and contribute to oxidative stress.
The regulation and distribution of iron in the body depends in part on ceruloplasmin and copper, so if ceruloplasmin and/or copper become deficient, then iron regulation gets impaired, potentially leading to anemia and/or extra oxidative stress in the body caused by unbound iron.
Supplement Intelligently, Not Randomly
Nutrients operate in a complex symphony, and it's best to test nutrient levels, understand how they work together, and then if appropriate, supplement intelligently rather than randomly or impulsively.
This is one of the things we do in the Bio-Individual Blueprint program to help people get from where they are now in their health to where they want to be. I invite you to check out our methodology by downloading the Bio-Individual Blueprint Roadmap and watching the walkthrough video.