Vitamin D Deficiency

Here is an email exchange I recently had:

November 06, 2009

Hi Jack,

I’ve been vegan for almost two years and am wondering about a skin condition I recently developed. I have a red flaky patch of skin right below the corner of my lip and above both eyelids. The patch is not itchy or yellowish, so I suspect it is not eczema. I am wondering if the patches are the result of a vitamin deficiency. I used to take a multivitamin, but I quit taking it because my skin took on a yellowish hue, especially in the winter when I eat more squash (and my doctor thought I might be getting too much beta-carotene). I now only take a B-complex vitamin. Is it possible that the skin patches are a sign that I’m not getting enough of a particular vitamin?

My response:

A lack of vitamin D can cause psoriasis in some cases, but other than D and B-vitamins, which it sounds like you are good on, I don’t know what it might be or if it is likely to be nutrition-related. It’s definitely not a common complaint I hear from people who are vegan.

November 14, 2009

Dear Jack,

I saw my primary care doctor this week and she speculated that I might have a vitamin D deficiency. I began taking supplements and going outside for 30 minutes a day around noon. The patches have all but disappeared in a matter of days. Just wanted to let you know in case you ever come across any other individuals with the same condition. I have since read more about the health problems associated with vitamin D deficiency, and I am thankful my deficiency manifested itself in a way that I was able to take notice and do something about it.

Addendum Nov 15, sent from a different reader:

I had ‘eczema’ for years every winter and when I started taking Vitamin D2, 2000 IU, it went away for good. I also had my 25-hydroxy-Vitamin D level tested and it was at the very lowest end of normal…. Any skin condition that’s worse in the winter (where UV is low in the winter) I would suspect Vitamin D deficiency.

6 Responses to “Vitamin D Deficiency”

  1. rick Says:

    Are you familiar with vegan sources of D3? Is there a new technology? It was my understanding that vegan sources of D3 were limited to sunlight/sunlamp because D3 suppplements are derived from either wool lanolin or fish oil. I see now that some companies are claiming to sell vegan D3, e.g.: or D3 derived from yeast (I thought that would instead be D2), e.g.:

  2. Jack Norris RD Says:

    I am not familiar with that vegan vitamin D3. I will look into it more.

    – Jack

  3. Rick Says:

    In a previous vitamin D post you referenced the April 2009 Hollick interview at As I recalled from that article, Hollick said that vitamin D blood levels last about three-days from D2 and two-weeks from D3 (about a fivefold difference). Unfortunately, I could not open that page today to confirm my memory of this aspect. Other than that, I had understood that short term blood levels from the same single dose of the two forms of the vitamin were identical.

    It seems to me therefore that in comparing daily intake of the two forms of the vitamin, equivalent doses of D3 and D2 should require an adjustment to accommodate for the difference in accumulated doses as consequence of the difference in how long they last in the bloodstream.

    Indeed, in his 2000 article, Hollick addresses this aspect:

    “Since vitamin D2 is approximately 30% as effective as vitamin D3 in maintaining serum 25-hydroxyvitamin D levels,up to three times as much vitamin D2 may be required to maintain sufficient levels. …Alternatively, either 1000 IU of vitamin D3 per day (available in most pharmacies) or 3000 IU of vitamin D2 per day is effective.” (references omitted)

    MF Hollick, MD, PhD n engl j med 357;3 july 19, 2007 p275

    In that article he calls for a threefold adjustment rather than the fivefold adjustment that I would have anticipated necessary from the 2009 interview, if I recall that article correctly.

    In another article from 2007, he says identical daily doses of the two forms of the vitamin maintain identical status:

    “CONCLUSION: A 1000 IU dose of vitamin D2 daily was as effective as 1000 IU vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and did not negatively influence serum 25-hydroxyvitamin D3 levels. Therefore, vitamin D2 is equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status.”

    J Clin Endocrinol Metab. 2008 Mar;93(3):677-81. Epub 2007 Dec 18

    Are you able please to shed any light on these apparent discrepancies? Do you think it reasonable that a higher daily dose of D2 than D3 is required to maintain the same blood levels?


  4. Jack Norris RD Says:


    I do not recommend increasing the amount of vitamin D2 in order to make up for it lasting less time in the blood because in the study where it was shown not to last as long, levels actually dropped below baseline after a few days. So it seems much better to take it regularly than to increase the amount. There is more research needed in this area before we know for sure what is the best way to take vitamin D2.

  5. Jack Norris RD Says:

    Update: After looking into it more, it appears that there is confusion on the manufacturer’s side and that this vitamin D is not actually D3 but rather D2.

  6. Rick Says:

    Thanks, Jack; I thought I had remembered D3 lasting two weeks and D2 only lasting three days. Now I see where I had read it!

    Still, I was not asking about taking it regularly versus increasing the amount. Assuming regular intake, I am asking whether, if daily intake recommendations are based on D3, then shouldn’t DAILY intake for D2 be adjusted upward threefold to fivefold to compensate for its lower accumulation over time due to it not lasting as long in the blood as D3?

    I realize that the same answer applies, that more research is needed before we know for sure, but is not an increase in D2 daily intake a reasonable resolution for the interim?

Leave a Reply