What and how the world is beginning to

learn about the importance of “Vitamin D”

Question: When is a Vitamin not a Vitamin?

Answer: When it is “Vitamin D”.



Special, 63-minute, “Vitamin D Only” Audio Files



The following files contain the very tightly edited “Vitamin D only” audio of our original podcast. These files have all of the non-Vitamin D (Security Now!) content removed, and they were further streamlined to remove all other audio annoyances. The resulting 63-minute audio is perfectly suited for sharing the Vitamin D podcast content with others who are not Security Now! listeners. The following files and formats are available for download with the provided links: Highest quality, 64kbps, mp3 audio file (30.2 mb)

This is a high-quality, single-channel audio file of the sort Leo normally provides for use with any media player that can handle standard MP3 files.

(30.2 mb) This is a high-quality, single-channel audio file of the sort Leo normally provides for use with any media player that can handle standard MP3 files. Smallest download, 16kbps, mp3 audio file (7.55 mb)

Since we're just talking, 64kbps can be overkill (though it certainly does sound the best). But if you'd prefer a smaller file, this one is probably all you need.

(7.55 mb) Since we're just talking, 64kbps can be overkill (though it certainly does sound the best). But if you'd prefer a smaller file, this one is probably all you need. Ready-to-Burn, Audio CD Cue/Bin file set (404 mb)

Since the audio now easily fits onto a standard audio CD, and since you might wish to share it with non-iPod or mp3 playing people, this ZIP file contains a standard Cue/Bin file set that can be loaded and burned by most CD burning software, to produce a standard audio CD, making sharing the content as easy as possible.

(404 mb) Since the audio now easily fits onto a standard audio CD, and since you might wish to share it with non-iPod or mp3 playing people, this ZIP file contains a standard Cue/Bin file set that can be loaded and burned by most CD burning software, to produce a standard audio CD, making sharing the content as easy as possible. Do-It-Yourself, high quality Stereo WAV (404 mb)

If you want the podcast content in any other format, this file provides the raw, full-fidelity, stereo WAV file from which all of the foregoing files were created. It can be packaged or compressed in any way you wish. The following files contain the very tightly edited “Vitamin D only” audio of our original podcast. These files have all of the non-Vitamin D (Security Now!) content removed, and they were further streamlined to remove all other audio annoyances. The resulting 63-minute audio is perfectly suited for sharing the Vitamin D podcast content with others who are not Security Now! listeners. The following files and formats are available for download with the provided links:

How to digest this page: (Hint: Not simply from top to bottom)



If you were to read this page without any additional introduction, from the top, you would doubtless wonder why I was making such a big deal about a "Vitamin."



So please scroll down toward the bottom, to the BLUE section of links to the many clinical trials and studies I have collected. BUT PLEASE DO NOT CLICK ON THEM YET. For now, just read each study's brief description and its conclusions. Doing both of these things should give you some sense for why Vitamin D might be significantly more important than you previously suspected. (And it's SO INEXPENSIVE and simple to supplement without any risk from increased sun exposure.)



Then come back up here to the top of the page and read from the beginning, knowing a bit more about what's in store. And once you get back down to the clinical studies details you'll have a much better sense for why you're there and why they probably matter.



And thanks for checking this out! I hope you'll be glad you did.

“Vitamin D” is in quotes here and above because it is not a vitamin at all — in its active form it is the most powerful steroid hormone in our bodies. Though it is surprisingly crucial to both our developmental and ongoing health and well being (as the many clinical studies provided below demonstrate), it is present in it's so-called “active form” in concentrations of only 20 to 50 picograms per liter of human blood (a “picogram” is a trillionth of a gram!)

So just a very tiny bit of this stuff goes a long way!

When human skin is exposed to sufficiently powerful ultraviolet (UV) radiation from sunlight, a form of cholesterol contained in our skin (“7-dehydrocholesterol”) is converted into the precursor of Vitamin D, called “cholecalciferol”. This is then converted by our liver into the inactive bulk storage form of vitamin D that blood tests measure (“25-hydroxyvitamin D”). Although Vitamin D is present in limited amounts in cod liver oil and some fatty fish (salmon, mackerel and tuna), it is essentially unavailable in metabolically useful quantities from dietary sources.

As we age, our skin gradually loses its youthful cholesterol and its ability to synthesize Vitamin D declines over time. Although it has not been widely studied, some reports indicate that by the age of 50, Vitamin D production has fallen to approximately 50% of its original rate, and by the age of 65 production will have fallen to just 25% of its original capability. And independent of age, the skin's melanin pigmentation — either from natural genetic racial coloration or tanning adaptation — acts to absorb much of the sun's visible and ultraviolet radiation. This skin darkening has the beneficial effect of protecting our skin from UV radiation damage, but at the expense of further reducing the skin's rate and capacity for Vitamin D production. (Melanin is 99.9% efficient in absorbing the energy from ultraviolet light, converting it into harmless heat energy.)

“Vitamin D” was misnamed when it was first discovered hundreds of years ago, before we knew where it came from or how it was made. By definition, it is not a “vitamin” because vitamins are not produced endogenously (internally), they must be obtained exogenously (externally) from dietary food sources.

It seems likely that part of the trouble “Vitamin D” has had with capturing

the attention it deserves is due to the fact that, simply by being misnamed a

“vitamin”, it has been lumped in with all of the other vitamins and nutrients,

and thus assumed to be available in sufficient quantity through our diet.

“Vitamin D” isn't even a nutrient! It comes from the sun, not from nutrition.

Vitamin D Science has another problem: Vitamin D is very inexpensive and cannot be patented.

Large and long, many-year double-blind placebo-controlled clinical trials with many participants can easily cost millions of dollars. But since Vitamin D is technically free (just go stand in the sun) or super-inexpensive (about 2.4 cents per day as a dietary supplement), no commercial pharmaceutical company wants to even think about it. Unlike synthetic chemicals to lower cholesterol, control blood sugar, lower high blood pressure or improve sexual performance, no large pharmaceutical company can make money selling vitamin D. And as the studies below demonstrate over and over, maintaining adequate levels of Vitamin D throughout a lifetime is both simple and inexpensive. Prospective study after study shows that Vitamin D is apparently highly effective in preventing many of the health problems that big pharmaceutical firms have invested millions of dollars in developing expensive drugs to cure. This puts such companies in the admittedly awkward position of not being big fans of health.

Vitamin D inexpensively promotes health.

So only University and some hospital affiliated researchers, with comparatively limited budgets, have any interest in exploring the health benefits of Vitamin D. And even when they, again and again, demonstrate surprising benefits from maintaining higher levels of vitamin D ... who's going to market and sell that information? Once again, there's no money in it. So, once again, although all of these professionally prepared reports and studies are freely available for access, download, and printing on the Internet, the general public never knows about is since there's no one running expensive prime-time commercials to sell it.

As you read the studies provided below, I predict that you are going to be

amazed and surprised and perhaps finally skeptical. You're going to wonder “if

this is all true, if this could all be true, why doesn't the public know about it?”

We see expensive commercials every night during prime time for expensive and patented pharmaceuticals that allow older men to urinate more easily and less often, but we never see any similar advertisements mentioning that study after study has shown that simply (and inexpensively) maintaining sufficient levels of Vitamin D can work to prevent rickets (that's well known) but also 17 types of cancer including pancreatic, colon/rectal, stomach, prostate, lung, breast, bladder, uterine, espousal, kidney, ovarian, multiple myeloma, non-hodgkin's lymphoma, and leukemia, lower blood pressure, improve immune system function (prevents colds and flu), autoimmune function, inflammation, multiple sclerosis, autism, allergies, preeclampsia, both type 1 and type 2 diabetes, osteoporosis (also well known) depression, muscle and bone weakness and generalized pain.

Looking at that long list of problems above, you may wonder how something, anything, could possibly “cure” all of those very different disease conditions. But that's thinking about Vitamin D backwards. Vitamin D doesn't “cure” anything. NONE of those things are supposed to go wrong in the first place. So Vitamin D simply allows our bodies to work the way they were designed to . . . because our bodies were designed to have much more Vitamin D circulating through them than most indoor-living Westerners do today.

The human race evolved, developed and emerged in sub-Saharan equatorial East Africa where, year round without seasons, we received the sunlight we needed everyday for our skin to manufacture all of the Vitamin D hormone we required from our skin's natural cholesterol. When we migrated away from the equator, natural selection quickly eliminated most of the melanin pigmentation from our skin in an attempt to compensate for the much weaker levels of UV radiation available for making Vitamin D. But then we went indoors and have been inadvertently starving our bodies of Vitamin D ever since.

A terrific state-of-the-art Vitamin D summary

After reading the original medical research studies provided below, I wondered what the popular press had to say about Vitamin D. So I purchased a number of inexpensive books to review. My favorite from among them is this book the “Vitamin D Prescription” that I recommend without hesitation. It very fairly and accurately recaps and summarizes in non-clinical non-medical language, all of the latest original research and findings regarding Vitamin D. If you were to read all of the fundamental research first, as I have, you would recognize it all in this book, but in much more readily accessible form. If you would like something more readily digestible, or if you want something for a family member or friend, this might be perfect. The book is available from Amazon for $14.99 USD at this direct link: http://amzn.com/1439229465

Vitamin D Related Resources

Retail Blood Tests

Unfortunately, purchasing your own blood tests is usually rather expensive. If you ask your doctor to add a few additional tests (like serum 25-hydroxyvitamin D) to your next regular annual test, insurance will likely pay for the test. But if you don't routinely see a doctor, or if for whatever reason you want to obtain your own tests, it's quite possible to do so. The following are two sources that I know of:

Life Extension Foundation — “LEF” offers retail blood testing through their affiliation with LabCorp, a national clinical testing laboratory with facilities everywhere. (There are four near me that I had to choose among.) After purchasing the test(s) online, you receive a packet send via postal mail or faster ways if you prefer. That is taken to the lab which draws blood and processes the tests. The results are electronically returned to LEF who makes them available to you online, by eMail, postal mail or fax (in any combination). Here's the link to Life Extension's Vitamin D (25-hydroxy) test. Since it is (as of this writing) $62.67 for non-members or $47.00 for members, with membership costing $75 per year, if you think you might be taking multiple tests, as I have been during my experiments, joining to get the lower price pays for itself pretty quickly. Here's the link to all of Life Extension's extensive selection of tests. Again, since the offer substantial discounts to members, becoming one can reduce the cost of even one expensive blood test.

Grass Root Health — I recently learned of this site, and their $40 "prick your finger at home" Vitamin D blood testing kit. SO I can't vouch for them in any way, but I wanted to pass on the information in case it might be useful to anyone.

Vitamin D IS HIGHLY TOXIC when ingested in

extremely high doses daily for many months !!! Our skin's natural sunlight-driven production of Vitamin D is internally regulated to limit the maximum rate at which Vitamin D can be produced. It has been estimated that approximately 10,000 to 20,000 IU of Vitamin D is generated by 20 to 30 minutes of full body exposure in direct overhead sunlight. Beyond that, continued exposure begins to degrade any additional Vitamin D produced to limit its total daily production. It is, therefore, impossible to overdose on Vitamin D obtained from sunlight, and there is no record that it has ever happened.



But no such limitation exists when high-potency Vitamin D supplements are ingested orally.



Although it is quite difficult to overdose on Vitamin D, YOU MUST TREAT IT WITH RESPECT. Its value lies in its power, but you want it to improve and not compromise your health. Follow the labels on supplements, educate yourself about dosages, if at all possible test your blood's Vitamin D level, check with your doctor, and be responsible.



John Jacob Cannell, M.D. and executive director of the Vitamin D Council has



has the following to say: “Because synthesis of 1,25(OH)2D (the most active metabolite of vitamin D) is tightly regulated, vitamin D toxicity usually occurs only if excessive doses (prescription or megavitamin) are taken. Vitamin D 1000ug (40,000 IU)/day produces toxicity within 1 to 4 months in infants. In adults, taking 1250 ug (50,000 IU)/day for several months can produce toxicity.” Our skin's natural sunlight-driven production of Vitamin D is internally regulated to limit the maximum rate at which Vitamin D can be produced. It has been estimated that approximately 10,000 to 20,000 IU of Vitamin D is generated by 20 to 30 minutes of full body exposure in direct overhead sunlight. Beyond that, continued exposure begins to degrade any additional Vitamin D produced to limit its total daily production. It is, therefore, impossible to overdose on Vitamin D obtained from sunlight, and there is no record that it has ever happened.Although it is quite difficult to overdose on Vitamin D, YOU MUST TREAT IT WITH RESPECT. Its value lies in its power, but you want it to improve and not compromise your health. Follow the labels on supplements, educate yourself about dosages, if at all possible test your blood's Vitamin D level, check with your doctor, and be responsible.John Jacob Cannell, M.D. and executive director of the Vitamin D Council has this to say about Vitamin D Toxicity The Merck Online Medical Manual has the following to say: “

Purchasing Vitamin D Supplements

I have been using the web site “iHerb.com” for many years and I recommend them without hesitation. An advantage for me is that they are located close enough that UPS Ground delivery is overnight, but I would use them if they were on the other side of the moon. Their service is perfect, their web site works well, and — most importantly — their prices are consistently the lowest anywhere.

5,000 IU “Now Foods” Vitamin D3, 120 capsules for $8.80

This is the Vitamin D3 I had chosen for my own use, and it's what I had been recommending to others. I have since switched to the Vitamin D from “Healthy Origins” (see below) because it is even less expensive than Now Foods and they are an equally good and trusted supplier.



Because Vitamin D3 (Cholecalciferol) is so potent and fat soluble, the capsules are tiny, filled with olive oil, and easy to swallow. The label instructs to take one 5,000 IU capsule every three days, for an average daily dosage of 5000/3 = 1667 IU/day. Since the 120 capsule bottle costs $8.80, taking one capsule every third day will last one full year, which is impossible to beat for the price.



“Day skipping” works well with Vitamin D3, since after being quickly metabolized by your liver into “25-hydroxy vitamin D”, that fat soluble metabolite has a half-life of at least three weeks in the body. So whatever regimen you choose will quickly "average out" to a nice even level in your blood.



Although you should never go “off label” to obtain a higher dosage without the advice of a doctor and/or keeping an eye on your important blood levels, especially calcium, this high-potency per capsule does make obtaining higher daily dosages extremely convenient.



You can also get similar quality in reduced dosage and in various capsule counts:

5,000 IU “Now Foods” Vitamin D3, 120 capsules for $8.80 This is the Vitamin D3 I had chosen for my own use, and it's what I had been recommending to others. I have since switched to the Vitamin D from “Healthy Origins” (see below) because it is even less expensive than Now Foods and they are an equally good and trusted supplier. Because Vitamin D3 (Cholecalciferol) is so potent and fat soluble, the capsules are tiny, filled with olive oil, and easy to swallow. The label instructs to take one 5,000 IU capsule every three days, for an average daily dosage of 5000/3 = 1667 IU/day. Since the 120 capsule bottle costs $8.80, taking one capsule every third day will last one full year, which is impossible to beat for the price. “Day skipping” works well with Vitamin D3, since after being quickly metabolized by your liver into “25-hydroxy vitamin D”, that fat soluble metabolite has a half-life of at least three weeks in the body. So whatever regimen you choose will quickly "average out" to a nice even level in your blood. Although you should never go “off label” to obtain a higher dosage without the advice of a doctor and/or keeping an eye on your important blood levels, especially calcium, this high-potency per capsule does make obtaining higher daily dosages extremely convenient. You can also get similar quality in reduced dosage and in various capsule counts: 2,000 IU “Now Foods” Vitamin D3, 120 capsules for $5.02

1,000 IU “Now Foods” Vitamin D3, 180 capsules for $5.02

1,000 IU “Now Foods” Vitamin D3, 360 capsules for $9.43





5,000 IU “Healthy Origins” Vitamin D3, 360 capsules for $14.98

This Vitamin D3 appeared on the iHerb site in August 2009, right around the time of the Vitamin D podcast. It's label suggests taking one per day which, frankly, even though it's three times the dosage suggested by the Now Foods label, is not something I would disagree with so long as its users always act responsibly with making sure there are no problems, rare as they might be, with hypercalcemia, which could affect some people who would be genetically sensitive to higher intakes of Vitamin D. PLEASE remember that Vitamin D can definitely be toxic when taken in large doses over an extended period of time.

5,000 IU “Healthy Origins” Vitamin D3, 360 capsules for $14.98 This Vitamin D3 appeared on the iHerb site in August 2009, right around the time of the Vitamin D podcast. It's label suggests taking one per day which, frankly, even though it's three times the dosage suggested by the Now Foods label, is not something I would disagree with so long as its users always act responsibly with making sure there are no problems, rare as they might be, with hypercalcemia, which could affect some people who would be genetically sensitive to higher intakes of Vitamin D. PLEASE remember that Vitamin D can definitely be toxic when taken in large doses over an extended period of time. There are so many available potencies and capsule counts of Healthy Origins Vitamin D3 that rather than listing them all, here's a search link of iHerb.com for: “Healthy Origins Vitamin D3” which should give you a page showing all of the many options of 1200, 2400, and 5000 IU Vitamin D3.

A Terrific Vitamin D Video Presentation

One last point about iHerb and Now Foods Vitamin D3: While you're browsing the pages, check out the customer feedback for the 5,000 IU capsules . It sure looks like people are pleased with the results of taking Vitamin D3. (At the time of this writing, the Healthy Origins D3 was too new to have many feedback postings.)

The YouTube video below is a VERY WORTHWHILE quite fast-paced, 58-minute presentation by Michael Holick, one of the leading Vitamin D researchers. (About 40 minutes into the presentation he gets into the many cancer and other preventive aspects of sufficient Vitamin D.)





http://www.youtube.com/v/Cq1t9WqOD-0 Click the video above to play embedded, or this link for large size:

Dr. John Jacob Cannell of the Vitamin D Council

This is the doctor (MD & Psychiatrist) who I mentioned during the podcast as working at the Atascadero State Mental Hospital where he had all of the patients on Vitamin D for its beneficial effects on their emotional state. During that time, an extremely serious influenza (flu) outbreak swept the hospital, causing the quarantining of the wards surrounding his on every side . . . while not one of his patients became sick, despite having had ample pre-quarantine contact with the adjoining wards. Today, everyone in the hospital takes vitamin D. Doctor Cannell is also the founder of The Vitamin D Council and, as you can probably tell from the video, he appears to really know his stuff . . .





http://www.youtube.com/v/--NqqB2nhBE Click the video above to play embedded, or this link for large size:

A news blurb by Science Central, Inc.

The following YouTube video news blurb, produced by “Science Central, Inc.” is just a random bit of further confirmation of the conclusions of the many studies and reviews on the topic, some of which I have described and provided in their entirety, as PDFs, below:





http://www.youtube.com/v/C7lGBT3oMiw Click the video above to play embedded, or this link for large size:

A 7-minute audio feature from “Living on Earth”, August 28th, 2009

It is not my intention to bury you in media. But seeing samples from many different sources helps make the point that the awakening to the Vitamin D problem is happening all over and is not an isolated “crackpot” phenomenon.



THIS LINK will take you to the Living on Earth program for August 28th,2009 titled “Skin Color and Vitamin D”. Note that the page also contains a complete textual transcript of the audio file for anyone who would also like to have that.



If at some future time that original source link above fails to work, you can download the original audio file in MP3 format with this local link hosted by GRC.

Topics in Vitamin D Health

The following collection of PDF files were gathered from freely available public Internet sources. Nothing was paid for — though some digging was sometimes required to locate a freely downloadable version of an article that was available only for purchase elsewhere — and all copyrights have been left intact and unchanged. So you should feel free to print or share anything here with anyone else. Also, the URLs of these documents are stable. They will not be changing or going away for the foreseeable future.

U.S. National Institute of Health (NIH) on Vitamin D Dietary Supplement Fact Sheet — Vitamin D:

This provides a good ultra-conservative take on the U.S. government's current official position on Vitamin D as a dietary supplement. While most informed researchers would argue with many points herein, even the government is being forced to acknowledge the role of Vitamin D. Check out the section on Cancer.



(I created this PDF from the nih.gov web site on 7/30/2009)

Clinical Research & Epidemiological Studies Vitamin D and calcium supplementation reduces cancer risk:

2007 - American Journal of Clinical Nutrition — 6 pages

This 4-year, population-based, double-blind, randomized placebo-controlled trial showed that the relative risk (RR) of all forms of cancer was reduced to 0.232 in women receiving 1100 IU of daily Vitamin D plus calcium compared to the placebo control group. (Please see the study for all details.)

This 4-year, population-based, double-blind, randomized placebo-controlled trial showed that the relative risk (RR) of all forms of cancer was reduced to 0.232 in women receiving 1100 IU of daily Vitamin D plus calcium compared to the placebo control group. (Please see the study for all details.) Prospective Study of Predictors of Vitamin D Status and Cancer in Men:

2006 - Journal of the National Cancer Institute — 9 pages

This is a statistical study based upon a cohort of 51,529 medical professionals aged 40-75 in 1986. From their analysis, an increase of 25 nmol/L (which is 10 ng/ml, the more commonly used units) of predicted serum 25-hydroxy Vitamin D, resulted in a 17% reduction in total cancer incidence, a 29% reduction in total cancer mortality, and a 45% reduction in digestive-system cancer mortality. (Please see the study for all details.)

This is a statistical study based upon a cohort of 51,529 medical professionals aged 40-75 in 1986. From their analysis, an increase of 25 nmol/L (which is 10 ng/ml, the more commonly used units) of predicted serum 25-hydroxy Vitamin D, resulted in a 17% reduction in total cancer incidence, a 29% reduction in total cancer mortality, and a 45% reduction in digestive-system cancer mortality. (Please see the study for all details.) Prevalence of Cardiovascular Risk Factors & Serum Vitamin D Levels in the U.S.:

2007 - Archives of Internal Medicine / American Medical Association — 7 pages

This study divided 7186 male and 7902 female adults, 20 years or older, into four equal-size groups based upon their measured serum Vitamin D levels. Comparing the lowest serum group (the lowest quartile) to the highest (the highest quartile), those with the lowest serum Vitamin D levels had 1.3 times the occurrence of hypertension (high blood pressure), 1.98 times the occurrence of diabetes mellitus, 2.29 times the occurrence of obesity, and 1.47 times the occurrence of high serum triglyceride levels. (Please see the study for all details.)

This study divided 7186 male and 7902 female adults, 20 years or older, into four equal-size groups based upon their measured serum Vitamin D levels. Comparing the lowest serum group (the lowest quartile) to the highest (the highest quartile), those with the lowest serum Vitamin D levels had 1.3 times the occurrence of hypertension (high blood pressure), 1.98 times the occurrence of diabetes mellitus, 2.29 times the occurrence of obesity, and 1.47 times the occurrence of high serum triglyceride levels. (Please see the study for all details.) 25-Hydroxyvitamin D and Risk of Myocardial Infarction in Men:

2008 - Archives of Internal Medicine / American Medical Association — 7 pages

This prospective statistical study examined 18,225 male health professionals aged 40 to 75 years who were free of cardiovascular disease at the time of blood collection. During 10 years of follow-up, 454 men developed nonfatal myocardial infarction (MI, heart attack) or fatal coronary heart disease. Compared with twice the number of age- and smoking status-matched control subjects, men deficient in Vitamin D (≤15 ng/mL) were 2.42 times more at risk for heart attack than those with sufficient serum Vitamin D (≥30 ng/mL). (Please see the study for all details.)

This prospective statistical study examined 18,225 male health professionals aged 40 to 75 years who were free of cardiovascular disease at the time of blood collection. During 10 years of follow-up, 454 men developed nonfatal myocardial infarction (MI, heart attack) or fatal coronary heart disease. Compared with twice the number of age- and smoking status-matched control subjects, men deficient in Vitamin D (≤15 ng/mL) were than those with sufficient serum Vitamin D (≥30 ng/mL). (Please see the study for all details.) Predictors of Vitamin D Status and Cancer Incidence in Men:

2006 - Journal of the National Cancer Institute — 9 pages

This is a report on a “prospective statistical study” meaning that they took an existing medical database of information and analyzed it carefully for statistically significant relationships of a specific nature. In this case, they were examining the relationship, if any, between serum (blood) levels of Vitamin D and incidents of cancer and cancer mortality in men. What they found was that every increase of 25 nmol/L (that's 10 ug/mL on the scale most often used) of serum Vitamin D was associated with a 17% reduction in total cancer incidence, a 29% reduction in total cancer mortality, and a 45% reduction in digestive-system cancer mortality. The study concluded, in addition to the above, that the Vitamin D supplementation required to achieve a 25 nmol/L (10 mg/mL) increment in Vitamin D serum levels was approximately 1500 IU/day. (Please see the study for all details.)

This is a report on a “prospective statistical study” meaning that they took an existing medical database of information and analyzed it carefully for statistically significant relationships of a specific nature. In this case, they were examining the relationship, if any, between serum (blood) levels of Vitamin D and incidents of cancer and cancer mortality in men. What they found was that every increase of 25 nmol/L (that's 10 ug/mL on the scale most often used) of serum Vitamin D was associated with a 17% reduction in total cancer incidence, a 29% reduction in total cancer mortality, and a 45% reduction in digestive-system cancer mortality. The study concluded, in addition to the above, that the Vitamin D supplementation required to achieve a 25 nmol/L (10 mg/mL) increment in Vitamin D serum levels was approximately 1500 IU/day. (Please see the study for all details.) Low Vitamin D Status Despite Abundant Sun Exposure:

2007 - The Journal of Clinical Endocrinology & Metabolism — 6 pages

An odd thing that Vitamin D researchers occasionally encounter is surprisingly low serum Vitamin D levels in people having plenty of exposure to the sun. This study examined students of the University of Hawaii and patrons of a Hawaiian skateboard shop who are regularly in the sun. (Please see the study for all details.)