Dietary Supplements | Natural Health Newsletter

Date: 01/10/2011    Written by: Jon Barron

Vitamin D Nonsense

On November 20th, the "prestigious" Institute of Medicine of the National Academies of Science (IOM) issued its eagerly awaited report on Dietary Reference Intakes for Calcium and Vitamin D. According to the study brief, "Calcium and vitamin D are two essential nutrients long known for their role in bone health. But since 2000, the public has heard conflicting messages about other benefits of these nutrients -- especially vitamin D -- and also about how much calcium and vitamin D they need to be healthy." And in fact, it was to help clarify this issue that the United States and Canadian governments asked the IOM to assess the current data on health outcomes associated with calcium and vitamin D, as well as update the nutrient reference values, known as Dietary Reference Intakes (DRIs).

In their report, the IOM proposed new reference values that the study's authors claim are based on much more information and higher-quality studies than were available when the values for these nutrients were first set in 1997. The IOM found that the evidence supports a role for vitamin D and calcium in bone health but not in other health conditions and not in significantly higher amounts.

As we will discuss, at least part of this conclusion is just plain silly -- the rest merely illogical. Unsurprisingly, the mainstream press simply parroted back a summary of the report with the usual over-the-top headlines:

But enough of picking on the press! It is now perfectly clear that the mainstream media no longer has the budget to support "investigative" journalism, with the possible exception of one or two major stories a year. All that can be expected when it comes to health and nutrition is that they parrot back the "news" they are given. That means that when a credentialed organization such as the IOM issues a report, the press will merely rework the press release issued by the researchers, add a "sexy" headline, and publish it as fact -- unquestioned, unexplored, and unchallenged. Unfortunately, that means that a lot of nonsense gets reported as "health fact" since credentials don't guarantee competence. In fact, they often mean corporate ties, hidden agendas, and huge bias. That means that if you want to truly understand the real story, you have to dig deeper and look at the underlying facts yourself or turn to alternative sources of information that you trust.

Interestingly, one such alternative source, the Council for Responsible Nutrition, a major spokes-group for the dietary supplement industry, was obsequiously cautious in their response to the IOM report, stating that the modestly increased DRI recommendations in the study were a step in the right direction, but regrettably fell short.  "Regrettably fell short"? That's the best you can do? Fortunately, after opening their response by sounding like a bunch of wusses (thank you Ed Rendell), they then went on to express some stronger concerns about the report. Unfortunately, they never actually confronted the serious flaws in the study that render all of its recommendations totally meaningless. So let's look at those flaws now.

Flaws in the IOM vitamin D study

(Note: I've discussed calcium in detail in several previous newsletters, so we'll focus on just the vitamin D aspects of the IOM study in this newsletter.)

The study's conclusions rest on four foundational pillars -- all of which I disagree with:

  • That vitamin D2 and D3 are interchangeable.
  • That previous studies ascribing health benefits to higher levels of vitamin D supplementation are contradictory and flawed.
  • That most Americans are maintaining serum 25 hydroxy vitamin D (25OHD) levels in the desirable 40 to 50 nmol/L range. Note: 25OHD is the recognized biomarker for vitamin D levels in the human body.
  • That supplemental vitamin D above 600-800 IU is inherently useless and unsafe (with up to 4,000 allowed under exceptional circumstances).

So let's take these four pillars on one at a time.

Vitamin D2 and D3 are interchangeable?

To quote from the study:

"Vitamin D, also known as calciferol, comprises a group of fat-soluble seco-sterols. The two major forms are vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is largely human-made and added to foods, whereas vitamin D3 (cholecalciferol) is synthesized in the skin of humans from 7-dehydrocholesterol and is also consumed in the diet via the intake of animal-based foods. Both vitamin D3 and vitamin D2 are synthesized commercially and found in dietary supplements or fortified foods. The D2 and D3 forms differ only in their side chain structure. The differences do not affect metabolism (i.e., activation) and both forms function as prohormones. When activated, the D2 and D3 forms have been reported to exhibit identical responses in the body."

Quite simply, this is not true. Vitamin D2 is much less effective in humans than D3. In fact, the metabolic pathways for D2 and D3 in the human body are clearly understood by the scientific community and are known to be anything but identical. The net result is that vitamin D2's potency is less than one third that of vitamin D3. But that's not all. The IOM report further states:

"The utility of serum 25OHD level as a biomarker of effect is less certain. Prentice et al. (2008) pointed out that the adequacy of the vitamin D supply in meeting functional requirements depends upon many factors, including the uptake of 25OHD by target cells, the rate of conversion of calcitriol and its delivery to target tissues, the expression and affinity of the VDR in target tissues, the responsiveness of cells to the activated VDR, and the efficiency of induced metabolic pathways. Nonetheless, despite these uncertainties, serum 25OHD levels can be regarded as a useful tool in considering vitamin D requirements; in fact, such measures are virtually the only tool available at this time."

Amusingly, this is actually a bit of a dance by the committee in regard to their own conclusions concerning the "identical" nature of D2 and D3. If you read between the lines, what they're saying is that D2 and D3 are only identical if you restrict your comparison to short term 25OHD levels. In other words, calling them identical requires you to close your eyes to all contradictory evidence.

So what am I talking about?

As it turns out, in addition to having markedly lower potency, D2 also has a significantly shorter duration of action relative to vitamin D3, which shows up in 25OHD levels…if you care to look. Specifically, both forms of vitamin D produce similar initial rises in serum 25OHD over the first 3 days. But 25OHD continues to rise with D3 supplementation, peaking at 14 days, whereas serum 25OHD falls rapidly in D2 treated subjects. In fact, levels fall so far with D2 supplementation that they are no different from baseline at 14 days.

This is proof positive that even a layman can understand that D2 and D3 are not metabolically identical in the human body. Is this important? You bet it is since this fact alone undercuts all of the IOM study's conclusions, as well as the committee's analysis of the existing body of work vis-à-vis vitamin D. As a fun side note, the prescription form of vitamin D is ergocalciferol, or vitamin D2, not the more effective human form, vitamin D3 or cholecalciferol. It's brilliant when you think about it! You pay a doctor several hundred dollars for a visit so he can prescribe vitamin D for you. You then have to pay over 20 times as much money for the prescription form of vitamin D that's only one third as effective as the stuff you can buy in the health food store for a fraction of the amount -- and without the need to pay a doctor for the prescription in the first place. Ya gotta love it!

The bottom line, as clearly stated in the American Journal of Clinical Nutrition, is that "vitamin D2 should not be regarded as a nutrient suitable for supplementation or fortification".

And with that in mind, let's take a look at the issue of contradictory studies that the IOM report focuses on.

Vitamin D studies are contradictory and flawed?

After reviewing nearly 1,000 published studies along with testimony from scientists and others, the experts on the IOM committee concluded that vitamin D does indeed play an important role in creating and maintaining strong bones. However, the committee also concluded that while further research was warranted into vitamin D's role in other health issues, at this point the evidence is mixed and inconclusive.  Or to quote from the study:

"While preliminary evidence, usually from mechanistic studies, experimental animal studies, and observational studies in humans, can generate exciting new hypotheses about nutrient--health relationships, evidence from these studies has limitations. For instance, even in well-designed, large-scale observational studies, it is difficult to isolate the effects of a single nutrient under investigation from the confounding effects of other nutrients and from non-nutrient factors.

"Outcomes related to cancer/neoplasms, cardiovascular disease and hypertension, diabetes and metabolic syndrome, falls and physical performance, immune functioning and autoimmune disorders, infections, neuropsychological functioning, and preeclampsia could not be linked reliably with calcium or vitamin D intake and were often conflicting. Although data related to cancer risk and vitamin D are potentially of interest, a relationship between cancer incidence and vitamin D (or calcium) nutriture is not adequately and causally demonstrated at present; indeed, for some cancers, there appears to be an increase in incidence associated with higher serum 25-hydroxyvitamin D (25OHD) concentrations or higher vitamin D intake."

But let's take another look at these "conflicting" vitamin D studies that the committee referred to -- this time separating the studies into two different piles: those conducted with vitamin D2 and those conducted with D3. Voila! Suddenly, the studies would most likely exhibit stunning consistency -- those conducted with D2 providing only marginal benefits (except for bone health and rickets), whereas those conducted with D3 would most likely produce significant, consistent benefits across a wide spectrum of conditions. And those conducted with D3 produced in the skin by exposure to the sun would most likely produce the biggest benefits of all. And in fact, a broad reading of the available literature is strongly supportive of these conclusions.

Now to be fair, the committee did point out that nailing down conclusive evidence about any health benefits associated with a specific nutrient in regard to a specific disease is extremely difficult because of the difficulty in isolating the effects of a single nutrient under investigation from the confounding effects of other nutrients and non-nutrient factors. But this does not negate the results of vitamin D3 studies which strongly suggest the health benefits of D3 supplementation. On the contrary, it merely speaks to the need for additional studies combined with a different way of looking at the data. Or to look at it another way, would you refuse to bring an umbrella if the weatherman said there was only an 80% chance of rain? Would you refuse to act until he said the odds were 100%?

Most Americans are already maintaining desirable levels of Vitamin D?

The IOM expressed "surprise" when it concluded that a majority of North Americans are meeting their needs for vitamin D, based on the IOM's determination of optimal blood levels of 25OHD needed to support calcium absorption and bone health. The IOM hypothesized that this surprise is likely due to food fortification, the increased use of supplements, and the body's ability to synthesize vitamin D from sun exposure. All well and good, except for three key issues:

  1. Which 250HD levels are they measuring: D2 or D3? As we've already learned, D2 provides only 1/3 the potency at equivalent levels. This is crucial in that one of the largest sources of supplemental vitamin D in the average diet is vitamin D fortified milk. And yes, milk is fortified with D2, not D3.
  2. Who's getting sun exposure in North America? Thanks to skin cancer scare mongering, everyone is covering up and using high SPF sunscreens. In fact, sunscreen is now a common addition to skin moisturizers and even makeup.
  3. But more significantly, the IOM guidelines stand in stark contrast to overwhelming scientific evidence that confirms the significant medical benefits of higher vitamin D levels. How high are we talking about? 50 to 100 nmol/L minimum, with some experts recommending as high as 250 -- and that's D3 based, not D2.

That supplemental vitamin D above 600- 800 IU is inherently unsafe?

The logic the committee used to reach their conclusions concerning the upper safe levels for vitamin D supplementation is a masterpiece of sophistry.

"The ULs for vitamin D were especially challenging because available data have focused on very high levels of intake that cause intoxication and little is known about the effects of chronic excess intake at lower levels."

Then again, they could just as easily have said that "little is known about the effects of long term chronic insufficiency" -- which is, in fact, the very essence of their mandate.

"The committee examined the existing data and followed an approach that would maximize public health protection. The observation that 10,000 IU (250 μg) of vitamin D per day was not associated with classic toxicity served as the starting point for adults."

Note: the committee clearly states that daily intake of 10,000 IU of vitamin D per day has not been associated with any form of classic toxicity. Further, according to the American Journal of Clinical Nutrition, one can take 10,000 IU of supplemental vitamin D every day, month after month safely, with no evidence of adverse effect. Unless you are hyper-sensitive, you must consume 50,000 IU a day for several months before hypercalcemia (the initial manifestation of vitamin D toxicity) might occur.

"This value was corrected for uncertainty by taking into consideration emerging data on adverse outcomes (e.g., all-cause mortality) which appeared to present at intakes lower than those associated with classic toxicity and at serum 25OHD concentrations previously considered to be at the high end of physiological values."

So, they dropped the 10,000 IU by a factor of 16 to account for uncertainty??!! And are they talking about emerging data based on D2 or D3 supplementation? They certainly aren't talking about D3 production in the skin -- considering that a light-skinned person will synthesize 20,000 IU of vitamin D in as little as 20 minutes sunbathing on a beach.


The committee's recommendations for the new DRI's for vitamin D are absurdly low. They ignore the fundamental differences between vitamin D2 and D3. And because they ignore those differences:

  • Their analysis of existing data is totally flawed
  • Their assessment of optimal 25OHD serum levels is based on fantasy and flies in the face of mounting scientific evidence.
  • And their caution on maximum safe levels of supplementation rests on mind boggling logic.

There is nothing in the committee's analysis to convince me to change my recommendations for vitamin D. These are:

  • Get daily, direct sunshine for 10 to 20 minutes, and make sure you don't completely cover your body whenever you're outside. And keep in mind that wearing sunscreen pretty much kills the ability of your skin to produce vitamin D from sunlight -- meaning, the more you cover up and/or use sunscreen, the more you need to supplement.
  • Lose weight, as vitamin D deficiency is more prevalent among overweight people.
  • Supplement with 1,000 to 2,000 IU of vitamin D3 daily. It's quite difficult to get enough of the vitamin from food sources, and it's difficult to overdose on vitamin D at these levels.

Click for Related Articles


    Submitted by Janice Condon on
    February 14, 2011 - 9:40pm

    Hello Dr Jon Barron- very much enjoy your articles and have high trust in them. I recently attended a Weston A. Price Foundation meeting, then bought their recommended book called Nourishing Traditions by Sally Fallon. As I understand it, we need fat in order to process the vitamin A and D in our bodies...natural fat from grass fed and pasture raised animals as well as coconut oil, organic eggs...the Foundation also recommends raw fermented foods and much other info which is making sense to me... much of this is new info for me....especially raw milk, as I have stayed away from dairy for a long time. They also have a soy alert. I was surprised to see the number of over 150 people at this meeting of our rather small college town.

    Have you heard of Weston Price Foundation? what do you think of it?

    Jan Condon, Chico CA

    Submitted by MARGRET on
    August 20, 2011 - 7:53am

    hi Jan, thanks for the very interesting vit. D2/3 informations - old quarrel with new data-
    In your letter to Dr. Barron you mention a soy alert. Would you be so kind to mail me information on how to get this report. Thank you in advance, Margret

    Submitted by steve on
    February 14, 2011 - 10:21pm

    Exelent article about Vits. D2&d3 and thier differances. They match exactly my understanding from the folks at Life Extension where I purchase all my supplements. I take 50000 IU a day or Vit.D3 daily and have done so for four years. Keep up the good work.

    Submitted by Al on
    February 16, 2011 - 2:30pm

    I am a 4 year bladder cancer survivor, a 3.5 year choroidal melanoma cancer survivor and also have had basal cell carcinomas from time to time. When I had the bladder diagnosed, my ND tested my vitamin D level and it was resting nicely in single digits. She immediately put me on a regimen to correct that and I now take 8000 IU per day to keep it at or around 80. I read a LOT of stuff that says that people are vitamin D deficient. Where did these people get an opposite view if I have seen nothing about adequate levels but lots about insufficient levels? A study in England measured D levels in known cancer patients and every one was deficient, most in single digits just as I was. I am with you Jon, this report does not pass my smell test.

    Submitted by Guest on
    August 9, 2011 - 9:08pm

    I agree. I was taking 5000 units per day and was still getting sick with colds/flu symptoms about once a month. After bloodwork showed I was still deficient, I doubled my amount to 10,000 and have not been sick in 6 months.

    Submitted by Vic on
    February 19, 2011 - 6:18am

    I enjoy your articles especially your through amount of research. The only thing that concerns me that often you appear to be critical of other authorities i.e. Dr.Mercola.

    At the same time I wouldn't want you to stop the debate, I guess my point is sometimes it comes across as being overstated. It is my opinion only I may be wrong.

    Submitted by Barbara DAngelo on
    February 19, 2011 - 10:47am

    Thank you for your analysis. When these "reports" come out I wonder what the motivation is for those trying to minimize the benefits of nutritional supplements. Can the D2 lobbyists be that pervasive? Is the sunscreen industry sending bribes? Or is it just "traditionally" trained MDs who have zero background in nutrition? I'm always amused by MDs' warnings about the dangers of supplements, as they blithely inject people with chemo and leave them burned and tattered from radiation and surgery. It's also interesting that research studies one variable at a time, and therefore if a potential subject consumes calcium, vitamin D and vitamin K, she is not included in a study of calcium. I believe the recent "shocker" showing that calcium is good for nothing only included subjects taking calcium carbonate without any other "confounding" supplements. Isn't it common knowledge that nutrients work in synchrony and as co-factors. P.S. Weston Price Foundation is wonderful! Check it out!

    Submitted by Guest on
    February 20, 2011 - 11:09am

    I have received other health information from you in the past found it helpful I would like to receive your newsletter.I've been diagnosted with crohns and would appricitate any info on that. Thanks Olive

    Submitted by Guest Dr P.C.Tatham on
    February 20, 2011 - 8:10pm

    every adult patient who comes to me is advised to take5000 iu Vit D3 daoily unless they are going to holiday in the tropics or have MS when they are advised to take 10 000 daily & check cblood levels after 6 months of therapy
    I do not know the W.Price foundation & would love to learn more as I was so facinated by his book on Nutrition & physical degeneration I regard it as one of my "bibles" on nutrition
    Thus has been a great article emphasising the total negetivity of conventional doctors & scientists, which is causing a huge amount of unnecessary suffering in the western world

    Submitted by walter Smith on
    March 11, 2011 - 12:28pm

    My wife and I have a 5 yr. old son who has no opportunity to play outside (we live in a townhouse complex and have no yard). My wife thinks that giving him a children's vitamin which contains 100 IU of D3 is sufficient. She will not allow me to give him a vitamin ( D3 ) that has 1000 IUs daily. My wife's doctor ( also is my son's doctor )
    also says my son is getting enough D3. Are they right or should I be giving him more, and how much.

    Submitted by Larry Hoover on
    March 20, 2011 - 3:05pm

    This article is the first I've seen from Jon Barron, after one of my email correspondents gave me a link to his webpage. I now subsribe to this newsletter.

    What is of particular significance to Jon Barron's comments about the Institute of Medicine of the National Academies of Science (IOM) and other institutions like it: that they ("insitutes")take on an aura of officialdom and influence government bureaucrats and politicians who don't have anything to loose if they simply parrot what the "officials" say.

    When our medical profession in this country is taken over by government officials following the sophistry of bureaucratized medical practitioners, these bureaucrats will be directing doctors to use certain procedures and will not allow them to use their own intelligence and discretion without severe personal and professional consequences.
    Thanks for people like Jon Barron who can think outside the box and communicate intelligently to debug the sophistry that controls much of officialdom.

    Submitted by J.P. Ditto on
    April 19, 2011 - 12:01pm

    Supurb article with unsurpassed research and comparison facts. Never stop investigating. This website is a Godsend!

    Submitted by Gues]Jennifer on
    May 4, 2011 - 7:51am

    I get newsletters from the Vitamin D Council, & that's where I learnt about the 25Hydroxy test. As I'm living in UK I thought I'd go for a test(on NHS & therefore gratis) but no my GP looked at me as though I was from planet Zog & did a test for calcium levels which were really quite high , This didn't seem to bother too much though.I added magnesium supplements to my mineral intake. Are all GPs this barmy?!!!

    Submitted by jan on
    May 26, 2011 - 12:09pm

    Vitamin D is required to cause calcium to be deposited in the bones (along with other minerals). Vitamin D is best absorbed in the presence of adequate intake of calcium, vitamin K, phosphate, potassium, magnesium, boron, zinc, vitamin B complexes, and Co-Q10. Essentially, your MD will avoid discussing much of this with you because most doctors are not educated beyond the most basic levels as to the details of proper nutritional balance. Occasionally barmy, too, I would add.

    Submitted by Karenina on
    July 7, 2012 - 9:32am

    Yes, most GPs don't have a clue about natural supplements, why? Simple, they want to make money from their medicines prescribed for their patients whereas nothing can be made financially while you take natural supplements. You can get your Vitamin D3 checked at the Birmingham hospital for £20. I have mine checked twice a year. I have not been ill or had the flu for three years now and I take 15,000iu during the autumn/winter and 10,000iu during the spring/summer seasons. As it is raining so much this summer I am still taking 15,000iu at the moment. The Vitamin D helps my progesterone cream to work better for me too. Yes the magnesium supplements are an excellent choice to the mineral intake.

    Submitted by Guest on
    June 21, 2011 - 1:48pm

    Vitamin D from the Sun is probably one of the best and most abundant sources we have (not to mention it's FREE). In fact, the Sun has been known to prevent cancer! This infographic explain the benefits of getting a little sun every now and then.

    Submitted by Kathy on
    August 8, 2011 - 7:32pm

    Thanks for the article Jon,

    I would like to raise a question about overweight and vitamin D deficiencies.
    I suspect that overweight is the consequence of a lifestyle that includes not much time outdoors in the sun. Perhaps it is not a cause of the D deficiency but another effect of the lifestyle that causes a deficiency in vitamin D...

    It also smacks, just a little, of "blame the victim"... most overweight try or have tried very hard to be normal - with poor guidance and ever mounting confusion and food degeneration.. It's a little like getting cancer because of overweight. No one is responsible for GM foods or chemical additives to our "food". Governments or school board rarely bother to provide enlightened, honest education about healthy eating and living habits. Most do not know to look elsewhere to people like yourself.
    Keep up your good work.

    Submitted by nathir on
    September 29, 2011 - 11:37pm

    thank you very much

    Submitted by [email protected] ir is Mimi on
    October 16, 2011 - 2:26am

    Here it is Mimi --the lost primer on vitamin that was missing for a long time. I hope u enjoy it and live forever. Love Dad

    Submitted by [email protected] on
    October 16, 2011 - 2:32am

    Some skinny on vitamin D --- read and live for ever--almost--love JC

    Submitted by DanO on
    August 2, 2012 - 10:00am

    Thanks, Jon for an unending supply of great Bio knowledge. Much research has been performed and documented on VitD. One of the best sites that I've gone to and get information from on VitD is vitaminDcouncil dot org. It is part of Dr. John Cannell's work. According to him, there has been no VitD toxicity levels at 200 iu/ml. That said, a 25OHD test about every six months is highly recommended I believe that these so called studies by entities that have conflicting financial support have an agenda that's beside facts and truth. As an FYI, Dr. Cannell does sell a VitD combo supplement that has the ingredients for the right kind of volume, etc., for a healthy outcome.

    Submitted by Chris on
    December 26, 2012 - 5:09pm

    Hello to the Baseline staff and writers (especially Jon), and thank you for all the information you put out.

    I have a question regarding sourcing of Vitamin D, D3 specifically since I'm not really all that interested in D2. I read in another one of your articles on dietary supplements that many vitamins and minerals are actually synthetically produced, with Vitamin D being from oil if I recall correctly (regardless, I got the idea there is a load of fake vitamins out there, too).

    I don't want to name specific brands in case you are worried of libel issues, but my question is with regards to supplementing. I would love to get out in the sun, but living in the Pacific Northwest see it very rarely throughout the winter. I have been taking a dropper to provide a good amount of D3 daily. The only other ingredients listed are d-alpha-tocopherol and medium chain fatty acids (from coconut and palm sources). So - is this a reliable, healthy source of Vitamin D, or could this synthetic form be among those bad ones you admonish against? IS there a safe Vitamin D3? I looked on your Baseline page to purchase from, but did not see one.

    Any information on this or recommendation would be amazing. Thank you again for your time and articles.

    Submitted by BaselineFoundation on
    December 27, 2012 - 11:12am

    The ingredients look clean

    Submitted by Mark on
    December 19, 2013 - 3:47pm

    Wouldn't it be better to take a naturally derived mineral and let our intuitive bodies and Mother Nature figure out what we need, instead of a " one pill " approach just like conventional doctors do today?

    Submitted by Andres on
    September 9, 2014 - 7:32pm

    From the journal paper that supposedly shows the difference between vitamin d2 and d3

    "Serum calciferol concentrations were measured at d 0, 1, and 3. The results are shown in Fig. 1. Baseline values of both calciferols were low, with the D3 concentration higher than the D2, as would be expected. However, the rise by d 1 was essentially identical for both calciferols, and at d 3 the serum levels of the two had fallen close to baseline and were virtually identical. This behavior indicates that absorption of the two calciferols was approximately equivalent."

    Let me emphasize the last part


    Equivalent meaning the same...

    Submitted by BaselineFoundation on
    September 15, 2014 - 6:56pm

    Andres, we are in awe that you actually took the time to go to the source study and read to that level of detail—and yet miss both the title of the article, which is in much larger print than anything else in the article, as well as the explanation of the statement you quoted.

    First, the title: "Vitamin D2 Is Much Less Effective than Vitamin D3 in Humans"

    And then if you just read two paragraphs past where you quoted, you will see how that quote is put in context.

    “The best measure of total exposure of the organism to an administered agent is given by AUC of the serum concentration against time. Here the greater potency of D3 was dramatically evident. AUC28 was 60.2 ± 23.4 ng·d/ml (150.5 ± 58.5 nmol·d/liter) for D2 and 204.7 ± 32.4 ng·d/ml (511.8 ± 80.9 nmol·dl) for D3 (P < 0.002). This is a more than 3-fold difference in potency.”

    Bottom line: From the journal paper that really does show the difference between D2 and D3. They are not equivalent. They are not the same.

    Submitted by MrsM on
    April 23, 2015 - 6:46am
    Tampa , Florida

    Hi Jon! Thanks so much for this article! I am darker skinned, and although I live in Florida, I am in indoors for most of the day. I have been undergoing fertility treatments for the past two years and have read that Vitamin D plays a huge role in female fertility. I have been taking 5000IU per day of D3. I am 40 years old and in good health. Is that too much?

    Submitted by Steve on
    October 27, 2016 - 2:25am

    Your being darker skinned means that it is harder for your skin to produce as much d3 as lighter skinned people.
    I am lighter skinned and take 40,000 iu per day and have done so for 2 years. I don't get colds or flu since taking at this level.
    You must also supplement with Vitamin K2 mk7 as well as this will prevent calcification of soft tissues.
    Your being darker skinned will mean you can take even more, especially if you don't get any sun exposure.
    The best way to tell is to have a blood test for serum25 and make sure your levels are at 100 - 120. (Some now saying even higher)
    If your MD won't do the test for you you can get a kit online. Just google Vitamin D blood test.

    Submitted by Debbie on
    May 24, 2015 - 4:12pm
    Abbotsford ,

    There is recent literature that disputes the use of vitamin D supplementation because non-dietary supplementation actually causes a chain of events that depletes other crucial minerals, especially magnesium. There is no disputing that many of us need vitamin D in higher levels in our bodies...the discussion is around how to make that happen. I have read some very thoughtful and convincing arguments that blanket Vitamin D supplementation is not the way to go and can, in fact, be very harmful.

    I would be interested in your comments.

    Submitted by BaselineFoundation on
    May 25, 2015 - 6:33pm

    Vitamin D--no matter its source, sunshine, food, or supplements-- requires and 'uses up' magnesium to convert into its active form in the blood. If taking large doses of Vitamin D, you need to take magnesium supplementation into consideration. You want to be sure you get adequate vitamin D, but as Jon Barron frequently points out, you should never think of supplements in isolation, but holistically.

    Learn more:


Add New Comment