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A Brief Look at the Importance of Ensuring Adequate Vitamin D Status

I've been working to put together a comprehensive look at why ensuring that you're getting enough vitamin D is one of the most important ways you can prevent disease and increase your lifespan.

My full report should be ready in a few days, but until then, here's a look at a few essential details on vitamin D and some of what it does in your body:

  • Decreases your risk of all types of cancer

  • Helps to maintain strong bones and teeth

  • Enhances the strength and efficiency of your immune system, which decreases your risk of developing autoimmune conditions like rheumatoid arthritis and lupus

  • Helps your body regulate its blood sugar levels, playing an important role in preventing type II diabetes

  • Lowers risk of developing Rickets (in childhood)

  • Helps to prevent high blood pressure

Since the 1980s and until just a few years ago, the conventional medical perspective on vitamin D was that you could get all that you need by exposing your arms and legs to sunlight for 10 minutes a day.

It's true that an excellent source of vitamin D is sunlight. Sunlight contains ultraviolet (UV) rays that come in three different lengths: UV-A, UV-B, and UV-C. UV-B rays are the ones that are capable of producing vitamin D in your body by acting on the cholesterol found in your skin.

The reason why conventional advice about getting 10 minutes of exposure to sunlight everyday is woefully simplistic is that the amount of UV-B rays that reach your skin and produce vitamin D depends on a variety of different factors, the main ones being:

  1. Skin Color: Lighter skin color allows deeper penetration by UV-B rays, which decreases the amount of sunlight exposure needed for adequate vitamin D production. So, the darker your skin, the harder it is for UV-B rays to penetrate it and produce vitamin D, increasing your need for sunlight exposure.

  2. Season: People living above 35 degrees latitude north or below 35 degrees latitude south receive little to no UV-B rays from early autumn to late spring.

  3. Altitude and Latitude: The higher you live above sea level, the greater exposure you have to UV-B rays. The higher you live above the equator, the less exposure you have to UV-B rays.

  4. Pollution and Clouds: Both decrease the number of UV-B rays that reach you.

  5. Age: As people age, natural degenerative changes that occur in skin make it harder for UV-B rays to convert cholesterol to vitamin D. Elderly people typically need to rely more on food sources than sunlight for their vitamin D needs.

So How Much Do You Need?

The current Dietary Reference Intakes by the Institute of Medicine range from 200 to 600 IU per day depending on age, with the U.S. upper limit for vitamin D being 2,000 IU per day. These numbers are woefully out of date, as they don't take into account a great deal of research on vitamin D and its effect on human health that's been published over the last several years.

Ultimately, the most responsible recommendation that I can make is to take a 1000 IU supplement every day - this applies to children and adults alike, even those who are already getting some vitamin D from an appropriate amount of cod liver oil. This number takes into account my own clinical experiences as well as the work and recommendations of Dr. Michael Holick of the Boston University Medical Center.

The only group of people that I can't recommend 1000 IUs for on a daily basis are those who live between 35 degrees south and 35 degrees north latitude and who get at least 15 minutes of sun exposure on their skin a few times a week. But even some of these people might need supplementation.

Most people should also strive to eat some foods that are naturally rich in vitamin D, such as:

Food Sources Serving Vitamin D (IU)
Wild salmon, canned 3 ounces 530
Cod liver oil 1 teaspoon 400
Sardines, canned 3 ounces 231
Organic egg yolk 1 medium 25

How to Test Your Vitamin D Status

If you plan on getting more than 1000 IU of vitamin D per day, I highly recommend that you have your blood level of vitamin D monitored about once every 6 months. Ask your doctor or laboratory for the 25(OH)D test, also known as the 25-hydroxyvitamin D test. Please note that some labs do a similar test called 1-25(OH)D test, which is not as accurate a marker of your vitamin D status.

If your test shows a level lower than 30 ng/ml (75 nmol/l), you have a higher than average risk for prostate and breast cancer, as well as autoimmune conditions like rheumatoid arthritis and lupus.

If your test shows a level higher than 70 ng/ml (175 nmol/l), you have a high risk of suffering from kidney stones, heart disease, and bone loss. Please know that while having too little vitamin D in your blood is a huge problem, having too much vitamin D in your blood can cause equally dangerous health problems.

I believe that a healthy range for the vast majority of people is between 50-60 ng/ml (125-150 nmol/l).

If you're looking for a whole food supplement with a generous amount of vitamin D-3, the one that I use and recommend can be found here:

Organic Whole Food Multi

For a comprehensive look at this topic, including guidelines on how to get the right amount of sun for your skin type, please view:

How to Make Sure that You Are Getting Enough Vitamin D for Your Best Health


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I was hoping for an extensive listing of healthy foods containing Vitamin D, but I appreciate the information given about Vitamin D. It is true that the importance of Vitamin D is misunderstood. And, both extreme levels of Vitamin D have far-reaching effects. The truth is that most people are deficient of this vitamin at one time or another due to the various factors mentioned, in addition to, consuming a nutritionally imbalanced diet.

Important to note is that Calcium taken with it increases the absorption of Vitamin D. Also noteworthy, is that low levels of Vitamin D affect not only our physical health, but also our mental health. So, if you have feeling very blue for more than a couple of weeks or have been diagnosed with clinical depression, chances are that your Vitamin D levels are too low. For those of us who are at an extremely low level and need quicker recovery, there is Vitamin D therapy that can be prescribed 50,000 IU taken once a week for 8 weeks. And, It MUST BE prescribed. It would be ineffective trying to consume that amount of IU with over-the-counter vitamin pills. Your body wouldn't be able to digest more than one pill at a time leading to wasted money and energy trying to do so.

Thanks again for your overview of Vitamin D. I'm looking forward to reading other articles. rg

Dear Rebecca, please note that it is not Calcium is needed for vitamin D absorption but quite opposite: vitamin D has to be present for Calcium absorption. According to latest research the minimum dose of vitamin D for adults should be 2000UI/day to achieve serum 25-hydroxyvitamin D level of 40-60 ng/ml regardless of intake of Calcium.


I read your query as to what foods contain vitamin D and your request for a list. I'm a colllege student and have to do a small paper on vitamin D and in researching and reading from different sites here is one I found that provides a list. I hope this helps.

We read recently that cows that are outdoors naturally have vitamin D in their milk. They seek out the sun to relax and absorb it. They get vitamin D by sunning, then licking it off of their hair which apparently absorbs it. This is then integrated into their milk.

I think that the connection between calcium, magnesium and vitamin D in raw milk is very interesting. If the cow is pastured, it will have the correct ratios of each, that we need, present in their milk. Most dairy cows are not pastured anymore, but are inside barns all day, so they would be low in natural vitamin D. Also, their milk is processed which destroys a lot of what is naturally in the milk, thus the artificial reintroduction of it back into the processed milk.

I would post where we read it, but we can't recall our source at the moment.

We found our source of our information. It is in the book, "The Family Cow" by Dirk van Loon, and published by Storey Publishing.

There is a bit more information on this subject in the book, as it mentions that vitamin D is also absorbed into the oils of the skin and so is absorbed by the cow in this way as well. I just thought that you might want the source of our information.

Hi Rebecca,

Not many foods contain vitamin D, so the list is quite short. The best source of Vitamin D is not in our foods though, it's present (biologically inactive) in our skin. This is synthesized into biological active Vitamin D through UV-B radiation (sun light). So the sun is your friend!


Hi Rebecca, I have compiled a list of 30 foods that contain vitamin d. Plus, you can learn how vitamin d is essential for us. Visit here for this list:

Hello Dr. Kim, I feel you are right that we need to be careful about getting too much Vitamin D. Recently I received an email(reproduced below)from health enthusiast Karen Van Cleef which sheds some much needed light on the subject.
Hi David,

I am fortunate to have some amazing
people in this group.

I learn so much from all of you and am
very grateful.

Last week I got an email from Charlotte
who warned me about something that
happened to her in regards to vitamin D.

Of all the vitamins, we know that vitamin
D is the one vitamin you need to be careful
with as taking too much can have detrimental

But everyone seems to be deficient now,
I mean just everyone. I am getting tons of
emails from many of you who have been
tested for vitamin D deficiency.

When the doctor told me I needed to take
all the hormones and vitamin D, I started
taking just the vitamin D.

I have been watching the studies on vitamin
D and breast cancer because my mother died
of breast cancer when she was 47 and I am
going to be 47 in a few months.

So these hormones and deficiencies and my
own mortality are heavy on my mind.

But after getting an email from Charlotte, I
have some concerns.

You see, Charlotte sent me some very
interesting info from Dr. Trevor Marshall.

Dr. Marshall's research can be found here:

Charlotte writes:

"Just want to tell u that I had the same results,
low vitamin D and I supplemented with vit D
too. That was NOT good. What people in general
don't know is that "vitamin D" is a hormone, it's
not a vitamin. There have been papers published
about the danger of supplementing with vitamin D.

Basically, the "vitamin D" u take as pills and
liquids will depress your immune system.
You might feel better in the short term, but
in the long term its not good.

I had a hidden infection that was making my
vitamin D levels low. Its not because you lack
vitamin D, but most probably because of
infection from pathogens (bacteria, virus)."

I am reviewing Dr. Marshall's research thoroughly
with the help of Dr. Adler and will report back when
I know more.

I am also going to be talking to other doctors
about vitamin D and will let you know when
those interviews are available.

And may all of us be balanced and
open to whatever it takes to bring us
to true optimum health.

Karen Van Cleef

I urge you to take a good look at this very informative and surprising website from Dr.Marshall below. It was a real eye-opener for me.

The Truth About Vitamin D: Fourteen Reasons Why Misunderstanding Endures.

Let us know what you think.

Thanks for your time.

This comment is true -- I had a good friend who was incredibly deficient in Vit D. At her doctor's advice, she took massive doses of Vitamin D2. As it turns out, this version of the Vitamin is incredibly toxic and it crashed her system, causing her body to reject all Vitamin D from foods. She had to move to a sunnier climate just to get by. Because she was a single mother without much income (and very sick), this took an epic effort.

D2 is toxic. Do not take it for any reason, no matter who prescribes it to you.

D3 is not toxic and is generally quite beneficial. That said, make sure it's a form that your body can absorb. I'm not sure if they synthesize Vitamin D, but would be surprised if they didn't. The synthetic forms of vitamins are generally not helpful and can be quite harmful. For example, the process of synthesizing them ends up creating "mirror molecules" which are the same form reversed. These cause harm in the body, instead of helping.

Further, there are 8 different factors in the full Vitamin D. Most Vitamin D supplements give you only one or two.

So the best form of Vitamin D is from food: egg yolks, butter, cream, liver and fish. The more these foods are modified (pasteurized, industrialized, processed, animals fed on inferior foods, such as cows feeding on other than grass, or salmon fed on artificial foods, etc.), the more the D is destroyed, and the less available the remaining D is.

I highly recommend Sally Fallon's "Nourishing Traditions" cookbook -- worth the margin notes alone. She also put out a great "diet book" called "Eat Fat, Lose Fat" which compresses the information quite a lot. Of course, the work of Weston Price is beyond compare, but sometimes hard to understand. Sally Fallon is the best at compressing the concepts and providing pragmatic advice (recipies, etc).

I thank you for the helpful imformation, Humans have lost almost all of thier intuitiveness when it comas to health and medecine, Mother earth knows what we need and has it available to us, and she charges her children nothing.

wanted to add that the natural vegan source of vitamin D is Mushrooms. Found that there is also a company, Monterey Mushrooms, that has done a coloborative study regarding using UV light exposure to enhance the naturally occuring D in mushrooms. Thought it might be of interest to those who choose a vegan diet.