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When a person receives frequent doses of unprotected, midday sun exposure, is taking a whole food supplement like cod liver oil necessary and how to test for this nutrient at home to ensure optimal levels.
Confusion abounds when the topic of cod liver oil comes up. On the one hand, you have respected and reputable nutritional organizations that urge a daily supplement of high vitamin cod liver oil as necessary for health. (1,2)
On the other hand, you have some alternative health sources that urge people not to take cod liver oil. (3)
Cod Liver Oil Still the Number One Superfood?
I prefer to read all sides of an argument with an open mind before coming to any conclusions…
The research to date suggests that a daily cod liver oil supplement is a good idea to maintain optimal health even when a person gets frequent sun exposure.
Of course, it is very important to add natural Vitamin K2 into the mix! This fat-soluble nutrient works to prevent A/D toxicity and improve absorption. Sources for the elusive X-Factor nutrient are emu oil, butter oil, and natto extract. (vetted sources)
Type of Processing Makes All the Difference
But, not just any cod liver oil will do! Like any supplement, how the oil is processed makes all the difference.
Dr. Michael Teplitsky explains the difference between 99% of the cod liver oils on the market and the kind you actually want to take. The “to avoid” brands are high heat processed industrialized oils.
The best cod liver oil is purified with no heat. This is the type of whole food supplement used for centuries and the kind you want in your pantry. (4)
Incidentally, nearly all the fish oils on the market are high heat industrialized oils too.
Bottom line? If you agree that a daily fish oil supplement is important to health, unheated virgin cod liver oil is the informed choice. (this is my preferred brand).
What about krill oil and how it compares to fish oil? While an excellent source of omega-3 fatty acids, krill oil does not supply fat-soluble vitamins like A and D.
My History Taking Cod Liver Oil
So, getting back to the main premise of this article, why do I take a daily dose of cod liver oil AND get frequent doses of midday sun?
To answer that question, I need to go back to when I first started taking cod liver oil nearly 20 years ago.
In 2002, the Weston A. Price Foundation recommended a daily teaspoon of high vitamin cod liver oil. It was the only organization that I knew about that was recommending cod liver oil. Almost everyone else in alternative health-related fields was on the fish oil bandwagon.
I had been taking fish oil since 1999, so it was an easy switch for me to start taking cod liver oil instead.
After all, cod liver oil offers the same valuable omega-3 fatty acids (DHA and EPA). In addition, it offers natural vitamins A and D which plain fish oil does not.
At the time, there was only one brand of high vitamin cod liver oil on the market (it is no longer available). I consumed 1 teaspoon per day which the label stated was 1000 IU of Vitamin D. Unfortunately, it was likely synthetic D because the product was high heat processed, which destroys the natural vitamins.
Note: Since 2015, I’ve taken Dropi virgin high vitamin cod liver oil sourced from the Atlantic due to concerns with Pacific ocean pollution (see my review of Dropi here).
20 Years Ago, Experts Advised Against Sun and CLO
What’s more, at that time in 2002, I was careful to skip my dose of cod liver oil on days that I got midday sun. This pattern of behavior was based on an article by Krispin Sullivan called Cod Liver Oil: The Number One Superfood. (5)
In her analysis, Krispin Sullivan warns against getting sun and taking cod liver oil. At that time, there just wasn’t much research out there about what happens to vitamin D levels when a person gets sun and takes cod liver oil.
Hence, 20 years ago, I did not mix the two out of an abundance of caution.
Since that time, experts have realized that the chances of overdosing on Vitamin D from whole food sources and the sun are slim to none.
Why Cod Liver Oil AND Midday Sun is Best
Fast forward to a typical weekend day for me now where I get about an hour or so of late morning/midday Florida sun with NO sunscreen while doing yard work or recreating. Do I skip my dose of high vitamin cod liver oil for the day like I used to back in the day? No.
I still take my usual daily dose of 1 teaspoon, which is about 400 IU of natural vitamin D.
Considering that the typical person gets about 20,000 IU of vitamin D from a short, nonburning dose of midday sun exposure (with no sunscreen which blocks Vitamin D production), a few hundred IU from a teaspoon of cod liver oil is quite small by comparison.
Even if someone gets sun every single day, he/she would develop a tan from doing so. Since skin melanin blocks the Vitamin D rays, increasingly longer jaunts in the sun are required to continue to get the same Vitamin D producing effects.
Experts Keep Upwardly Revising Optimal Vitamin D Levels
In recent years, much more has been learned about vitamin D deficiency and its optimal levels. A lot of evidence has been gathered that getting sun and taking cod liver oil at the same time is not dangerous. In fact, the combo is beneficial.
For example, back in 2002, the optimal blood level of vitamin D using the 25(OH)D test was considered to be just 30-35 ng/ml.
That is considered a deficiency level today!
Current thinking is that anything less than 50-60 ng/ml is deficient! Optimal levels are currently considered to be 50-80 ng/ml and for those with cancer and heart disease (or any other autoimmune disorder), the levels should really be at 80-100 ng/ml.
Vitamin D Levels and COVID
In fact, I was at my primary care doctor just recently, and he told me that his clinical experience shows that 60-80 ng/ml is optimal for preventing serious symptoms from the novel coronavirus.
He went on to say that every single patient of his that has COVID complications has low Vitamin D.
Why could this be? Because vitamin D essentially acts as a natural steroid hormone in the body, powerfully acting to reduce inflammation in the body.
Who needs to reduce inflammation? Nearly everyone, right?
Sun and Cod Liver Oil. No Downside
In short, the vitamin D levels that would have been considered dangerous just a few years ago are now considered optimal!
This is because so little was known about it 20 years ago.
We now know that higher is better and that to get into “overdose” range (above 100 ng/ml), you really would have to be taking prescription-strength vitamin D drops or synthetic D2 in isolation.
It seems virtually impossible to get into overdose levels using a whole food like cod liver oil. In fact, such a case has never been reported from what I’ve been able to find in the research.
Getting vitamin D from the sun and from cod liver oil on a daily basis appears to have no downside whatsoever.
In fact, it seems a rather dangerous proposition to health to not get sun and just take cod liver oil!
Research Shows Vitamin D from Food Not Enough
I know from years of taking cod liver oil that I personally have absolutely no chance of getting my blood levels into optimal range unless I get frequent doses of sun AND take high vitamin cod liver oil on a daily basis.
Cod liver oil as a whole food ideally needs to be combined with the sun for optimal effect.
Dr. Reinhold Vieth of the Mount Sinai Hospital in Toronto cites 3 studies in a letter to the American Journal of Clinical Nutrition that show that maintaining even a deficiency vitamin D blood level of 32 ng/ml requires 4000 IU of vitamin D per day! (6)
4000 IU vitamin D is about 1 teaspoon per day of fish eggs, the densest source of Vitamin D on the planet. Shockingly, this amount will only maintain your vitamin D at deficiency levels!
If that doesn’t tell you to get some sun along with your daily cod liver oil dose, I’m not sure what will!
Traditional Peoples Got Sun and Ate Vitamin D Rich Foods
If you think about it, this approach makes perfect sense.
Traditional peoples in the tropics got plenty of sun on a daily basis and still ate plenty of vitamin D rich foods.
It seems that building up vitamin D levels quite high in the warm months to take you through the winter months when you don’t get much or any sun (but still consume cod liver oil and other vitamin D rich foods) is the way to go.
A seasonal cycling of vitamin D levels is completely natural. To stay in optimal range all year round requires building to the upper end of the spectrum in the summer (~70-80 ng/ml) and then falling back to the lower end of the optimal spectrum (~50-60 ng/ml) in the winter.
Avoid High Dose Vitamin D Drops and Pills
Some people take high dose Vitamin D drops or pills as a potentially easier and more convenient alternative. Is this safe?
While such an approach may be necessary for the infirm or those who are otherwise unable to get out into the sun, for the average person, it is a better approach to stick with whole foods like high vitamin cod liver oil combined with sensible sunning.
Taking nutrients in isolation, especially one as powerful as Vitamin D, can risk excessive levels. Concerning side effects from Vitamin D drops/pills have been reported as well. These include a buildup of calcium in the blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones. (7)
Such side effects have never been reports from high vitamin cod liver oil and sun from what I’ve been able to find in the research.
If you absolutely must take high dose Vitamin D, always do so under the care of a knowledgeable physician.
Testing Vitamin D Levels at Home
If you have any concern about taking cod liver oil and sensible, nonburning sun exposure (midday is best when the vitamin D rays are at their peak), I would strongly advise investing in a finger prick home vitamin D test after 90 days of actively seeking midday sun exposure and continue taking your daily cod liver oil supplement.
It takes a few weeks at minimum for vitamin D levels to rise which is why you need to wait a while to take the test after you start getting sun exposure along with your daily cod liver oil.
Hopefully, this article gives you food for thought (literally) that it is a good idea to get sensible, midday sun exposure during the warm summer months while still consuming your daily cod liver oil supplement.
If you have any doubts, do both for 90 days and then order this inexpensive, finger pinprick home vitamin D test (you don’t even need a prescription to order one).
I have yet to see or hear of anyone getting above 70 ng/ml (or anywhere close) with regular sun exposure and cod liver oil together. The danger of not getting your vitamin D levels into this optimal range is far more serious!
References
(1) Weston A. Price Foundation
(2) Price Pottenger Foundation
(3) Important Cod Liver Oil Update
(4) Is Cod Liver Oil Healthy?
(5) Cod Liver Oil: Number One Superfood
(6) More evidence that vitamin D requirements are much, much higher than traditionally recommended amounts
(7) What is Vitamin D Toxicity, Mayo Clinic
Hooray for the glorious sun! Whenever a conversation turns to what's the best sunscreen, I always boast that I use an all-natural sunscreen, and that it's a traditional one used effectively for thousands of years, at least. When I have people's attention, and they're ready to hear about whatever magic herbal ointment I'm going to describe, I let it out: "It's called a hat."
What an informative, thoughtful post! This is something I've never looked into…thanks so much for sharing with us at Two for Tuesdays this week =)
Welcome Jean! So glad you clicked over from Katie's space – hope you find the info here helpful in your wellness adventure!
I just stumbled upon your website while reading kitchen stewardship! The article on vitamin D and cod liver oil could not be more welcome! I, too have been concerned about Dr Mercola's recent comments as to whether to go on taking Cod Liver Oil. I belong to WAPF and so I have continued to take CLO while spending at least 20 minutes in the sun here in Calif in the summer. I spend time in Fl in the winter and stay brown but my D levels were still low. I am taking D3 at 4000 a day hoping to get levels up
It is so great to find your site and I will look forward to lots of good info from you Jean
I loved this post – I am always promoting sun without sunscreen and I get all sorts of flack. I ordered some of the CLO from Green Pastures today! Thanks for linking it to Two for Tuesdays.
Great question .. I think Dr. Mercola pushes his own product at the exclusion of reason sometimes. I think his stance on cod liver oil is primarily to boost the sales of his competing product krill oil. Why doesn't he promote Green Pastures brand? He says he is also concerned about sustainability for cod as one of the reasons, then why not promote Green Pastures brand skate oil instead? Because he doesn't make any money on it.
I agree with him on so many things and it seems the things we agree on are the same things that he doesn't make a buck on. I could be completely wrong here, but I am dubious of his opinion where he has a product involved. Selling product in and of itself is no problem, but I have seen a pattern over the years with him that where he sells a product – it seems to skew his opinion.
Hi, Sarah. I've been following your blog for a while now, and I've got a question for you. Why do you trust Dr. Mercola on so many things even though he has not been "completely forthcoming" on this front? Do you ever worry that he may not be sharing the full picture on other topics as well?
Good post, Sarah.
That Green Pasture's combo of fermented CLO + butter oil with a little cinnamon flavor is actually tolerable.
Sarah,
thanks so much for this post!!! I've been wondering about this question myself and have actually skipped my CLO on days I'm going to be in the sun very much. I really didn't know how to go about researching it, so I appreciate you taking the time to research it and report. I do have a question–do you ever take or what are your thoughts about Flax seed oil and Evening Primrose Oil? I know they are different from Cod Liver oil. Do they have a needed place in our diets too?
Sarah – I totally agree with all you have said here, great post and there is so much useful information here. I believe that most of mainstream information about Vitamin D is so short sighted because most of what we eat is synthetic, and medical authorities are always cautioning against taking too much Vitamin D because those synthetic versions are dangerous, period.
Synthetic Vitamin D is prescribed or recommended for patients because their natural Vitamin D sources are either so low or completely non-existent. Anyone who takes the synthetic version of any nutrient is going to run into problems sooner or later.
It is very common for people to try and quantify how much of this or that we should be getting daily – such as in fat, calories, or cholesterol, but for some reason there is much less emphasis on how much of various vitamins and minerals we should get daily, and everything we read in the media is always on the "minimum requirement" scale, which as you pointed out is way too low.
So yes, like you, I take my fermented cod liver oil daily, whether I am getting sun or not, because it's natural and won't cause toxic reactions in my body like synthetic vitamin supplements and foods that are fortified with Vitamin D like pasteurized milk. I only learned this about 3 years ago, so I think I'm still building up stores in my body from years of neglect.
I actually know someone who never burns when she is out in the sun and eats a very processed diet, and on more than one occasion she has pointed out that I eat healthy food most of the time and I still do burn on occasion, but she is the opposite. Although I cannot explain this phenomenon, I still believe it is much better to receive nutrients from natural sources than to be deficient and hope for the best with processed foods.