My thinking on this topic has evolved as the research has changed. Click here to see a more recent article on the topic, and here for a podcast with updated information.
In the last two weeks alone three articles have appeared in the scientific press about new studies reporting on vitamin D’s many crucial roles in the body. Along with promoting strong bones, a healthy immune system and protection against some types of cancer, recent studies suggest vitamin D can treat heart failure, protect against heart attacks and reduce the risk of death from both cardiovascular and overall causes.
Exposure to sunlight may have protective effects when it comes to melanoma. Despite conventional wisdom that tells us to avoid sun exposure at all costs, it turns out that the vitamin D our bodies synthesize when exposed to UV light is a first line of defense against developing melanoma.
In an article published on June 9 in Archives of Internal Medicine, scientists reported that low levels of vitamin D are associated with a higher risk of myocardial infarction (heart attack) in men. The study showed that rates of cardiovascular disease-related deaths are increased at higher latitudes and during the winter months, and are lower at lower altitudes.
In an article published in the July issue of the Journal of Cardiovascular Pharmacology, on June 12, researchers found that vitamin D directly contributes to cardiovascular fitness. In fact, University of Michigan pharmacologist Robert U. Simpson, Ph.D. thinks it’s apt to call vitamin D “the heart tranquilizer”. Simpson and his team discovered that treatments with activated vitamin D prevented heart muscle cells from hypertrophy, a condition in which the heart becomes enlarged and overworked in people with heart failure.
Finally, in a study published on June 23 in the Archives of Internal Medicine, a team of Austrian scientists revealed that low blood levels of vitamin D appear to have an increased risk of death overall and from cardiovascular causes. Harald Donbig, M.D. and his colleagues studied 25-hydroxyvitamin D and 1,25 dihydroxyvitamin D levels in 3,258 consecutive patients (average age 62 years) who were scheduled for coronary angiography testing at a single medical center between 1997 and 2000.
During 7.7 years of follow-up, death rates from any cause and from cardiovascular causes were higher among individuals in the lower one-half of 25-hydroxyvitamin D levels and the lowest one-fourth of 1,25-dihydroxyvitamin D levels. These associations remained when researchers controlled for other factors such as coronary artery disease, physical activity and co-occurring diseases.
So what does all this mean to you? A recent consensus panel estimated that about 50 – 60 percent of older individuals in North America and the rest of the world do not have satisfactory vitamin D status, and the situation is similar for younger individuals. Blood levels of vitamin D lower than 20 to 30 nanograms per milliliter have been associated with falls, fractures, cancer, autoimmune dysfunction, cardiovascular disease and hypertension.
Low 25-hydroxyvitamin D levels are also correlated with markers of inflammation such as C-reactive protein, as well as signs of oxidative damage to cells, Donbig’s study revealed. In a previous article, I explained that inflammation and oxidative damage (not cholesterol) are the primary causes of the worldwide heart disease epidemic. Inflammation and oxidative damage are also contributing factors to diabetes, metabolic syndrome, cancer and many other diseases.
So how does vitamin D work its magic? It acts as a potent hormone in more than a dozen types of tissues and cells in the body, regulating expression of essential genes and rapidly activating already expressed enzymes and proteins. In the heart, vitamin D binds to specific vitamin D receptors and produces its “calming”, protective effects.
There are essentially three ways to obtain vitamin D: exposure to UV light, food and supplements. The most effective of all of these methods is exposure to sunlight. Full-body exposure of pale skin to summer sunshine for 30 minutes without clothing or sunscreen can result in the synthesis of between 10,000 and 20,000 IU of vitamin D. At most latitudes outside of the tropics, however, there are substantial portions of the year during which vitamin D cannot be obtained from sunlight; additionally, environmental factors including pollution and the presence of buildings can reduce the availability of UVB light.
In northern latitudes or during winter months when the sun isn’t shining, I recommend taking 1 tsp./day of high-vitamin cod liver oil (I recommend Extra Virgin Cod Liver Oil from Rosita as my preferred cod liver oil product) to ensure adequate vitamin D (and vitamin A) intake. You can also eat vitamin D-rich foods such as herring, duck eggs, bluefin tuna, trout, eel, mackerel, sardines, chicken eggs, beef liver and pork. If you follow this approach further supplementation should not be necessary.
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Before closing, I must mention (briefly) the issue of vitamin D toxicity. Vitamin D is widely considered to be the most toxic of all vitamins, and dire warnings are often issued to avoid excess sun exposure and vitamin D in the diet on that basis. The discussion of vitamin D toxicity has failed to take into account the interaction between vitamins A, D and K. Several lines of evidence suggest that vitamin D toxicity actually results from relative nutrient deficiencies of vitamins A and K.
So, the solution is not to avoid sun exposure or sources of vitamin D in the diet. Rather, it ensure adequate vitamin D intake (through sunlight and food) and to increase the intake (through diet and/or supplements) of vitamins A & K. Stay tuned for a future post on the interaction between vitamins A, D & K and their relevance to human health.
- Throw away your sunscreen. Use coconut and sesame oil if needed, and moderate your exposure to sun to avoid frequent sunburn.
- Get an hour or two of exposure to sunlight each day if possible. Don’t cover your skin (or your child’s skin) completely when out in the sun.
- In northern latitudes or during winter months when the sun isn’t shining, take 1 tsp./day of high-vitamin cod liver oil (I recommend Extra Virgin Cod Liver Oil from Rosita as my preferred cod liver oil product) to ensure adequate vitamin A & D intake.
- Eat vitamin D-rich foods such as herring, duck eggs, bluefin tuna, trout, eel, mackerel, sardines, chicken eggs, beef liver and pork.
- Make sure to eat enough vitamin K. Primary sources in the diet are natto, hard and soft cheeses, egg yolks, sauerkraut, butter and other fermented foods. Make sure to choose dairy products from grass-fed animals if possible.
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This may be a dumb questions, but who is “THS”?
I have for some time searched an answer to a question about synthesizing Vitamin D from sunlight: Showering BEFORE sun exposure. I see lots of opinions about whether showering AFTER sun exposure “washes off” the Vitamin D. But nowhere do I see anything about showering beforehand.
My understanding is that as Vitamin D is a fat soluble vitamin, it requires you to have body oils on your skin before you can synthesize sunlight. If you shower before going into the sun (or swim a lot at the beach or at the pool), you are likely washing off your natural body oils. Are there any studies showing that showering beforehand defeats the purpose of sun exposure?
And how long would one have to wait after showering or swimming for sun exposure to do its job?
I’m thinking of countries like Australia, which have high rates of skin cancer, but possibly not adequate Vitamin D intake.
I’d appreciate a response from anyone — haven’t seen this addressed by you, can someone point me in the right direction?
I’ve been told years ago to apply almond oil to my skin as a carrier for vitamin D before going out in the sunlight. Especially after showering or if my skin is dry. I did this for my children and now my grandchildren.
I just heard you on a radio station in regards to a vitamin d suppliment with boron and other stuff added to it, you also recommended to take a red Krill oil with it. You said you had made a deal with a supplement company. First bottle was 4.95 for shipping. I want this how do I get it
If you wanted to take a Vitamin D substitute – just as a fallback and particularly if you don’t get regular sun exposure – what dose and frequency would you take? I had taken 2000 IU twice a day, but after reading this will probably cut back and just take 2000 IU once in morning.
Hi Dr Davies
I am enormously interested in your views on Vitamin D and the consequences of its excess. My educational background is non-medical/non-scientific and my interest in D arose from having dysregulated D myself. In order to find doctors who understood my condition, I pretty much had to learn everything I could first.
Australia is in the midst of a debate centred around the government wanting to add Vitamin D to our food supply. I and others are adamantly against this from what we have learned about D ourselves. Your book Vitamin D Disarray is on order so as yet I’ve only read snippets of your writing that I could find online but I am so in agreement with your views and delighted to find a medical specialist/academic voicing his views.
I am putting together a document to send to various professors and government agencies here in Australia and would love if perhaps you could give it a quick read when I’m done to pick up any glaring errors I may make in medical facts pertaining to D. If that might be possible, may I ask you to email me at [email protected] or let me know some way I might send this paper to you.
Thank you and regards
I have just, I am afraid, come across your reply to my note to you of May4th about Vitamin D, in which I told you of my opinion about it being related to the coronary ‘epidmic’ of the 20th century. I need to correct a misapprehension, for which I wasentirely responsible in not making myself clear. My opinion is that excess not deficiency of Vitamin D is what is involved.
I have spelled out my reasoning in a pamphlet entitled “Vitamin D in Disarray” in which I seek also to demolish the idea that geographic latitude is related to the incidence of certain diseases like cancer, MS and cardio -vascular.
I would like you to read this if you would, and would be glad to send it to you if I could have a postal address. I would wish for as severe a criticism as appropriate. I am incidenntally a retired cardiologist, living in Switzer-land , with along interest in Vitamin D. I have probably not taken enough account of the influence of the other vitamins which you mention.
Best regards Hywel Davies MD FRCP FACP (attached for the record only).
I enjoyed this article, and found it to be a very reasonable one, emphasizing that it is a very important substance, which is perfectly true (it controls hundreds of genes). I also approve of exposure to sunshine, as they advise. A few things are a bit doubtful, like saying that is the most toxic of all the vitamins – it is certainly true that it is toxic, but it is not a vitamin in the real sense. It was only called one because it was discovered at the same time as the others.
The natural Vitamin D seems superior to the synthetic, too and codliver oil much more innocuous unless taken in excess. The great problem is that there are all those non-clinical enthusiasts pushing the synthetic stuff and being believed and quoted, when the better work is indicating that the range of safety is quite narrow. What I am trying to do now is throw some light on the possibility that Vitamin D was the cause of all the heart disease in the 20th century. It is not so far-fetched. A good topic for some young person to take up, I would think.
All the best,
I agree that D deficiency may well have played a significant role in the CHD epidemic. But I also believe that vitamin K2 deficiency has also played a role. As you know, the fat-soluble vitamins A, D, K2 and E act synergistically, and any excess of one combined with a deficiency of another can be problematic. Vitamin K2 regulates calcium metabolism and when it’s deficient, calcium gets put into the soft tissues where it doesn’t belong – causing heart disease. Overall, though, I tend to think the rise in consumption of industrial seed oils and refined carbohydrates is more responsible for heart disease than deficiency of fat soluble vitamins. Thanks for your comment.
I just got back from a trip and haven’t had the chance to read the article Ken linked to. My first reaction was incredulity, for exactly the same reasons you pointed out. We evolved in a vitamin D-rich environment and it’s extremely unlikely that D would be the cause of disease for this reason.
I just followed that link and it’s some of the most misleading drivel I’ve ever read. The claim that rickets isn’t caused by vitamin D deficiency is ludicrous and contradicts hundreds, if not thousands of experiments. The experiment is very simple: you feed a mammal a D-deficient diet. It develops rickets. You can block this by giving it vitamin D or UV light. Case closed.
Furthermore, the idea that vitamin D contributes to chronic disease doesn’t make a shred of sense. We evolved outdoors in a high-sun environment with high levels of vitamin D in our blood. The idea that getting vitamin D from the sun could be unhealthy requires a vivid imagination.
Your writing is clear and concise and graphics are excellent. Unfortunately, you are just repeating outdated mainstream dogma about vitamin D. You need to be more skeptical. See http://bacteriality.com/2007/09/15/vitamind/
Awesome article. Very informative and helpful! Thanks for sharing!
Thanks for your feedback and kind words!
Yes, I’ve definitely been influenced by Price’s work and the Foundation. I’ll check out the “Whole Health Source” blog you suggest.
I’ve read almost all of Masterjohn’s articles and have corresponded with him frequently on the Weston A. Price Yahoo group. I actually wrote a 20-page research paper on Activator X (K2) a few months ago so I’m quite familiar with his work!
Hi Chris, great blog! You’re a strong thinker and a good writer. I just discovered your blog and added it to my Google reader. I see you’ve been influenced by Weston Price, right on. I also have a blog you might enjoy; it’s along the same lines: Whole Health Source. The link should appear on my comment.
I’ve been publishing a lot about K2 MK-4 (activator X) lately. Have you read Chris Masterjohn’s activator X article on the WAP website? I highly recommend it.