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All,

 

After bashing on the Huffington Post for their poor coverage of yesterday's fish oil protects against Alzheimer's disease study, I want to be fair. Today they've got a pretty thorough and well-researched article on vitamin D. They advocate three things I can agree with:

  • The best way to get vitamin D is via modest sun exposure and supplements if necessary depending on your latitude/climate/lifestyle
  • The serum vitamin D level to target is 30-50 ng/ml (75-125 nmol/L) You don't want to be too high or too low.
  • The best way to determine how much to supplement is to get a blood test, and then titrate your supplement level to get into the 30-50 ngl/ml range by starting with these dosages:
    • 100 IU (2.5 mcg) per day increases vitamin D blood levels 1 ng/ml (2.5 nmol/L).
    • 500 IU (12.5 mcg) per day increases vitamin D blood levels 5 ng/ml (12.5 nmol/L).
    • 1000 IU (25 mcg) per day increases vitamin D blood levels 10 ng/ml (25 nmol/L).
    • 2000 IU (50 mcg) per day increases vitamin D blood levels 20 ng/ml (50 nmol/L).

Thoughts on the article, and the wisdom of the approach to vitamin D it advocates?

 

--Dean

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This is an important and somewhat controversial subject. The article is OK, but obviously not as comprehensive and nuanced as we favor around here :). For a much more nuanced and comprehensive discussion, see the archives, where Michael R. and Al P.  among others discussed optimum levels vs. all-cause mortality. Unfortunately, that demands access to the archives. I have the discussion archived in my emails, and I could simply copy and paste the whole chain, but I am not clear on the ethics/legality/good manners/best practices of reposting such emails (given that some of the participants are no longer active so I can't even ask for permission), so from an abundance of caution, I am going to refrain. But, for those of you who don't delete their CR-related emails, just perform a search of the COMM list (I use gmail) with search terms "optimum vitamin D Michael" and the chain starts on 12/22/2011 and goes on through the middle of 2012 (pretty long). I used to delete my CR emails, but given that the archives were always iffy with access, I wised up and stopped deleting them a few years ago - I'm glad I did as I now have my own "CR archives" and only regret that I have not been doing it since the beginning (though of course, I only got gmail in 2004 through an invitation, so that would have been a hard limit anyway). Take note kids - don't rely on things like "streaming", "cloud", "internet" for data you may need access to - for a variety of reasons, data can disappear or be no longer accessible through those means, therefore, it is always good to have your personal local storage (a bit of a pain, but can be invaluable) - that's true for everything: papers, journals, music, film etc... if you have a copy, you won't be as vulnerable to "404 Not Found". 

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Thanks Tom,

 

That's good advice, both about looking in the email list archives, and about not relying solely on cloud storage for critical data. That's one reason I've squirrelled away a full mirror of the entire 400-page cold exposure thread. I'd hate to lose all that effort...

 

Regarding the email archives, and that vitamin D thread in particular. They are accessible online, if you're a CR email list subscriber. Here is the link to the full archives (password required) at least from 2006-present - unfortunately there was a lot of good information pre-2006 that isn't available anymore, at least online as far as I know.  Also unfortunate is the fact that these archives don't appear to be (easily) searchable.

 

Here is a link directly to the archives from December 2011 when optimal vitamin D levels were discussed. Although I see several posts from Michael, I can't seem to find the one you're referring to on 12/22/2011. I do see a lot of other familiar names, like you (TomB), Al Pater, Saul Lubkin, Paul McGlothin, jwwright, Conrad Roland, Khurram, Tim C, Peggy Diamond, Apricot043.

 

And look at all those interesting topics - just in that single month!

 

Ah the good old days of the active CR email list...

 

--Dean

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Unfortunately, the archives don't work for me. Through a miracle, I actually have the password I was using back then for the crcomm list, but it doesn't appear to work - and clicking on the "remind" thing doesn't work either, so... out of luck. So I can't search the archives to dig up that thread, but I can give a bit more color on that first post, initiated by Michael - he kicked it off by discussing this study:

 

1: Zittermann A, Iodice S, Pilz S, Grant WB, Bagnardi V, Gandini S. Vitamin D
deficiency and mortality risk in the general population: a meta-analysis of
prospective cohort studies. Am J Clin Nutr. 2011 Dec 14. [Epub ahead of print]
PubMed PMID: 22170374.

 

And then Shane Keating responded and it snowballed from there.

 

Anyhow, I don't know if this is the right place to discuss the ins and outs of the archives, so I'm going to quit that tangent.

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Just one more OT thing: to clarify, Dean, when you said "unfortunately there was a lot of good information pre-2006 that isn't available anymore" you meant specifically COMM archives, right? Because I personally have emails from the main list in my gmail account going back to 2004 - the first CR email I have is from Al P. titled "CR, thyroid hormone and longevity" from 07/04/2004 :)... unfortunately, for some time (can't remember how long), I'd only keep those CR emails that interested me, and deleted stuff that didn't, like "in vitro cells of pregnant mice, blah, blah, blah".

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Tom,

 

Dean, when you said "unfortunately there was a lot of good information pre-2006 that isn't available anymore" you meant specifically COMM archives, right? Because I personally have emails from the main list in my gmail account going back to 2004

 

The next part of my statement was "..., at least online, as far as I know". Unfortunately I can't search your email archives. I guess I could have been more explicit and said "...at least publicly-accessible online...". 

 

--Dean

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Tom and others,

 

For those who have a CR-Community email list account (or want to sign up for one), here is a link to the 2011 post where Michael starts the discussion of optimal vitamin D levels.  Ironically, the GIF image of a figure from the paper Michael references in that post (stored at photo-hosting site imageshack.us) gives a 404 error... I suspect someday the same thing will happen with all my imgur.com links... That's one reason I squirrelled away the complete webpage for each of the cold exposure thread pages, and printed them to a giant (42MB, 400pg) PDF...

 

--Dean

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I thought the below paper gives a good idea of what blood levels vitamin D should be for minimum all-cause mortality of various ages, races and both sexes.

 

 

Is there a reverse J-shaped association between 25-hydroxyvitamin D and all-cause mortality? Results from the U.S. nationally representative NHANES.
Sempos CT, Durazo-Arvizu RA, Dawson-Hughes B, Yetley EA, Looker AC, Schleicher RL, Cao G, Burt V, Kramer H, Bailey RL, Dwyer JT, Zhang X, Gahche J, Coates PM, Picciano MF.
J Clin Endocrinol Metab. 2013 Jul;98(7):3001-9. doi: 10.1210/jc.2013-1333. Epub 2013 May 10.
PMID: 23666975 Free PMC Article
 
Abstract
 
CONTEXT:
 
A reverse J-shaped association between serum 25-hydroxyvitamin D (25[OH]D) concentration and all-cause mortality was suggested in a 9-year follow-up (1991-2000) analysis of the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994).
 
OBJECTIVE:
 
Our objective was to repeat the analyses with 6 years additional follow-up to evaluate whether the association persists through 15 years of follow-up.
 
PARTICIPANTS:
 
The study included 15 099 participants aged ≥ 20 years with 3784 deaths.
 
MAIN OUTCOME MEASURE:
 
Relative risk (RR) of death from all causes was adjusted for age, sex, race/ethnicity, and season using 2 Poisson regression approaches: traditional categorical and cubic splines. Results were given for 9 25(OH)D levels: <20, 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 74, 75 to 99 (reference), 100 to 119, and ≥ 120 nmol/L.
 
RESULTS:
 
The reverse J-shaped association became stronger with longer follow-up and was not affected by excluding deaths within the first 3 years of follow-up. Similar results were found from both statistical approaches for levels <20 through 119 nmol/L. Adjusted RR (95% confidence interval [CI]) estimates for all levels <60 nmol/L were significantly >1 compared with the reference group. The nadir of risk was 81 nmol/L (95% CI, 73-90 nmol/L). For 25(OH)D ≥ 120 nmol/L, results (RR, 95% CI) were slightly different using traditional categorical (1.5, 1.02-2.3) and cubic splines approaches (1.2, 0.9-1.4). The association appeared in men, women, adults ages 20 to 64 years, and non-Hispanic whites but was weaker in older adults. The study was too small to evaluate the association in non-Hispanic black and Mexican-American adults.
 
CONCLUSIONS:
 
A reverse J-shaped association between serum 25(OH)D and all-cause mortality appears to be real. It is uncertain whether the association is causal.
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  • 1 month later...
  • The best way to determine how much to supplement is to get a blood test, and then titrate your supplement level to get into the 30-50 ngl/ml range by starting with these dosages:...

This approach does not take into account the body weight.

 

I am using an online calculator that take also into account the body weight  along with the actual and target levels. Adding that parameter makes more sense since because vitamin d is a fat-soluble vitamin and the weight is a better indication of your body fat than nothing :D.

Also, there is no recommendation to the maintenance dose after reaching the desired level.

But I was not able to induce the formula used with a quick multiple linear regression.

 

In the past, I have used their  free online test to estimate my Vitamin D Level. According to the delivered report, the calculation is based on over 30 formula and the precision is plus/minus 8 ng/ml.

My online result was 16.5 ng/l and my lab result was 11.5 (difference: 5ng) so the announced accuracy of +/- 8ng was respected. That is why I trust their approach that need to be confirmed with a new lab test.

 

Tasbin

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Tasbin,

 

Welcome to the CR Forums! 

 

You wrote:

  • The best way to determine how much to supplement is to get a blood test, and then titrate your supplement level to get into the 30-50 ngl/ml range by starting with these dosages:...

 

This approach does not take into account the body weight.

 

Very interesting point. Here is something I didn't know or ever really think about, but you appear to be correct.

 

People with more body fat seem to require more exogenous vitamin D (from sun, food, or supplements) to "move the needle" on their serum level of vitamin D [1], because body fat act as a 'sink' for vitamin D. In other words, the more body fat you've got, the more D you need to add before your fat sink finishes soaking it up and therefore leaves enough in your bloodstream to do all the good things vitamin D does.

 

Below is the relevant graph from [1] from nearly 18,000 healthy people who self-reported their supplemental vitamin D intake and then had their serum vitamin D measured. Note these were folks from Alberta Canada, where they get very little vitamin D from the sun, even in summertime. Different curves represent different body weight categories. I've added a red horizontal dashed line at the (pretty widely accepted serum) target vitamin D level of 100 nmol/L (equivalently, 40 ng/ml). I've dropped vertical dash lines where the curves for various body weight categories intersection this horizontal target line:

 

lWy8P3m.png

 

Eyeballing where the vertical lines intersect the X-axis, it appears to me that a good starting point for so-called "underweight" and normal weight individuals is around 2000 IU/day of vitamin D, assuming if you don't get any vitamin D from the sun. For overweight people it looks like about 2700 IU/day is the right place to start, and for obese folks it looks like about 5500 IU/day. 

 

These seem like the right level to start one's vitamin D supplementation strategy. As you say, the level of supplementation you should start with varies based on your body weight (or more accurately, fat mass).

 

But I stick by my original advice - one should titrate one's vitamin D supplementation up or down from these baseline supplementation levels (i.e. ~2000 IU/day for thin folks) based on blood testing in order to target a serum D level of ~100 nmol/L or ~40 ng/ml.

 

--Dean

 

--------

[1] PLoS One. 2014 Nov 5;9(11):e111265. doi: 10.1371/journal.pone.0111265.

eCollection 2014.
 
The importance of body weight for the dose response relationship of oral vitamin 
D supplementation and serum 25-hydroxyvitamin D in healthy volunteers.
 
Ekwaru JP(1), Zwicker JD(2), Holick MF(3), Giovannucci E(4), Veugelers PJ(1).
 
Author information: 
(1)School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
(2)School of Public Policy, University of Calgary, Calgary, Alberta, Canada.
(3)Section of Endocrinology, Nutrition and Diabetes, Department of Medicine,
Boston University School of Medicine, Boston, Massachusetts, United States of
America. (4)Harvard School of Public Health, Departments of Nutrition and
Epidemiology, Boston, Massachusetts, United States of America.
 
Unlike vitamin D recommendations by the Institute of Medicine, the Clinical
Practice Guidelines by the Endocrine Society acknowledge body weight
differentials and recommend obese subjects be given two to three times more
vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine
Society also acknowledges that there are no good studies that clearly justify
this. In this study we examined the combined effect of vitamin D supplementation 
and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy
volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum
25(OH)D from 17,614 healthy adult volunteers participating in a preventive health
program. This program encourages the use of vitamin D supplementation and
monitors its use and serum 25(OH)D and serum calcium levels. Participants
reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had
serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response
relationship between vitamin D supplementation and serum 25(OH)D followed an
exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000
IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per
1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI,
relative to absolute body weight, was found to be the better determinant of
25(OH)D. Relative to normal weight subjects, obese and overweight participants
had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower,
respectively (P<0.001). We did not observe any increase in the risk for
hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D
supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher
for overweight subjects relative to normal weight subjects. This observational
study provides body weight specific recommendations to achieve 25(OH)D targets.
 
PMCID: PMC4220998
PMID: 25372709 
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As usual, you are quite obsessive/devoted to every subject with your lengthy and evidence-based response to the point that I sometimes confuse you with the forum itself :rolleyes:

 

 You did not comment the maintenance phase after reaching the desired level.

 

So i suppose, that after reaching it  and confirmed by a blood testing, you stick to the same dose and test it periodically. If it is higher that your target, you will normally stop/reduce  the dosage for a while (and how long) and then take it again (and how much) through a 'trial and error' process.

Digression:I am wondering what could be the effect on the vitamin d level during a rapid weight loss of a obese person which already have a high level and how the body cope with that "rush". I know that with sun exposure, you cannot overdose it but in case of massive "release", I have no idea.
 

Edited by tasbin
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Tasbin,

 

As usual, you are quite obsessive/devoted to every subject with your lengthy and evidence-based response to the point that I sometimes confuse you with the forum itself  :rolleyes:

 

I guess I'll interpret that as a compliment...

 

You did not comment the maintenance phase after reaching the desired level.

 

I didn't think it was necessary. The folks in the study I posted (PMID 25372709) were (presumably) already in steady state - those levels (e.g. 2000 IU/day for thin folks) were the levels it took to put (and presumably keep) them at the target of 100 nmol/L serum vitamin D.

 

So i suppose, that after reaching it  and confirmed by a blood testing, you stick to the same dose and test it periodically. If it is higher that your target, you will normally stop/reduce  the dosage for a while (and how long) and then take it again (and how much) through a 'trial and error' process.

 

Yes, exactly. That's what I meant by 'titrate'. Sorry to use such an unfamiliar word. Perhaps 'adjust' would have been more intelligible.

 

Digression:I am wondering what could be the effect on the vitamin d level during a rapid weight loss of a obese person which already have a high level and how the body cope with that "rush". I know that with sun exposure, you cannot overdose it but in case of massive "release", I have no idea.

 

My gut says it would be very hard to overdose on vitamin D released from fat during weight loss. I'd be much more concerned about the weight-loss induced release of other toxins sequestered in fat cells (e.g. heavy metals, pesticide residues, etc.). Heck, the extra circulating vitamin D might even help avoid or mitigate the damage from the simultaneously released toxins!

 

--Dean

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For everyones information, if you get on the website of the  American Academy of Enviromental Medicine on the front page and it can also be found on you tube. There is a great video on a lecture by Ty Vincent M.D. on vitamin D supplementation.  He recommends a daily dose of 10,000 iu to achieve a 150 - 200 ng/ml level for good health.

 

Dr Bennett

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On Vitamin D supplementation. I have a history of severe food and pollen allergies, in fact I only know of two other individuals that are affected as much as I am. I became suspicious recently about what my vitamin D level might be and I wondered if it might be low.  If you listen to the lecture by Dr Ty Vincent a physician who specializes in the care of individuals with vitamin D deficiencies, you quickly learn that vitamin D is very involved in the functioning immune system. I had my levels checked 5 weeks ago and found I was severely deficient for vitamin D on my lab report. So I followed Dr Vincent's suggestion and have been on a daily dose of 10,000 i.u. of vitamin D. Well what a difference it has made to my general well being. My sinuses are generally always running and congested because of the pollens.  I feel so much better after after the supplementation. So if you suffer from allergies you also want to have your vitamin D  levels checked and give it a try supplementing with vitamin D.  Want to say HI to Saul!

 

Dr Bennett

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I have lost my entire post. it is so frustrating !

 

Anyway, I do not have the patience to rewrite everything but I would like to share with you some studies mentionning some equations to the Vitamin D dosage depending on your target level.

Cholecalciferol loading dose guideline for vitamin D-deficient adults.

A Predictive Equation to Guide Vitamin D Replacement Dose in Patients

 

Notice that none of them take into account the body fat but only weight. It might be probably link to fact that the fat-soluble Vitamin D can circulate freely in the body(sorry I lost the reference, I have just read it yesterday in one of those papers :angry:  )

 

Also a study supports the position of Dean on the optimal vitamin D3 daily intake of 2000IU

Edited by tasbin
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Tasbin,

 

Thanks for the additional info on adjusting vitamin D dosage based on body weight / fat mass.

 

I have lost my entire post. it is so frustrating !

 

Yes, extremely frustrating.

 

It's too late now, but see this thread for helpful tips on using these forums, and in particular this post about how to recover lost drafts of posts you are in the middle of composing. It will come in handy the next time it happens...

 

--Dean

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One person data point:  I find that taking 50,000 IU twice per month keeps me at a good level -- for example, 41.6 ng/mL on 02/25/2016. I've been using the BIO-TECH D3-50, 100 (dry powder) capsules for many years -- if I recall correctly, based on a recommendation from "Rodney" as a reasonable non-prescription online source. This is the only supplement that I've been taking for quite a while now.

 

[My doctor mentioned some think that up to 60 ng/mL might be good for preventing osteoporosis.]

 

Todd

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Hi, as a first time poster I hope this is not a dumb question, but how clear is it whether the association between Vitamin D levels in the blood and various good health markers/outcomes is causative or not?  In particular there is some speculation that solar UV exposure causes NO production in the skin which results in improved circulatory health and possibly other benefits.  For one example of many see the TED talk:

 

http://www.ted.com/talks/richard_weller_could_the_sun_be_good_for_your_heart

 

Is there evidence which indicates whether NO production by sunlight exposure is responsible for all/some of/none of the link seen  between vitamin D levels and health?

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  • 3 weeks later...

All,

 

Dr. Greger is in the middle of a series on vitamin D. In today's video (embedded below), he talked about optimal vitamin D dosing. Based on a public health organization's recommendation, he (and they) recommend against regular test of vitamin D. Instead, the recommendation he has is for all adults is to get 2000 IU / day of Vitamin D from sun or supplements, and not to worry about overdoing it unless you are consistently pushing it to more than 10,000 IU / day. He says obese or elderly folks may need more than the 2000 IU / day, as we discussed above. 

 

But what about that U- or J-shaped mortality curve in  Al posted about above, and that Michael has described as well?

 

Dr. Greger cites a 2014 meta-analysis [1] of 32 studies of vitamin D and all-cause mortality. Here is the needle plot showing the hazard ratio of being in the lowest category of serum vitamin D vs the highest category for each of the studies:

 

aM6cXzc.png

 

As you can see, all the studies found benefit from being in the group with the highest vitamin D. But how high was that, and more importantly, is there such a thing as too high a vitamin D level?

 

Apparently not, at least in any reasonably range. Here are the figures from [1] showing the risk of all-cause mortality as a function of serum vitamin D level averaged those same 32 studies (left) and for each individual study plotted separately (right):

 

utGQGlp.png    K8TEX7L.png

 

It looks like all-cause mortality reaches it's minimum somewhere between 30 and 40 ng/ml, and is flat for any reasonable value of serum vitamin D beyond that - apparently without any uptick in mortality with higher serum vitamin D, as other studies (like Al's above) have reported previously. 

 

But despite the apparently all-cause mortality harmlessness of serum vitamin D levels greater than 40 ng/ml, it doesn't seem to be worth pushing higher than that, given the lack of all-cause mortality benefit from having it any higher. Here are a couple good quotes from [1]:

 

The present analysis also suggests that serum 25(OH)D concentrations of less than 30 ng/mL may be too low for safety.

 

A target range of 25(OH)D of greater than 30 ng/mL could be achieved in most individuals by intake of approximately 1000 IU per day of vitamin D3, 12 which is one quarter the National Academy of Sciences---Institute of Medicine tolerable upper level of intake of 4000 IU per day at ages 9 years and older.

 

The Endocrine Society has established a tolerable upper-limit intake of 10 000 IU per day at ages 19 years and older.12 Doses of vitamin D3 below 10 000 IU per day in adults have not been associated with toxicity, and serum 25(OH)D concentrations less than 200 ng/mL are generally not considered toxic.12 This leaves a considerable margin of safety for efforts to raise the population concentration of 25(OH)D to 40 ng/mL.

 

I've personally been taking the amount Dr Greger recommends (2000 IU / day) plus getting modest sun exposure during the summer months and have found that indeed it brings my serum vitamin D level to between 30 and 40 ng/ml. 

 

--Dean

 

 

------------

[1] Am J Public Health. 2014 Aug;104(8):e43-50. doi: 10.2105/AJPH.2014.302034. Epub

2014 Jun 12.

Meta-analysis of all-cause mortality according to serum 25-hydroxyvitamin D.

Garland CF(1), Kim JJ, Mohr SB, Gorham ED, Grant WB, Giovannucci EL, Baggerly L,
Hofflich H, Ramsdell JW, Zeng K, Heaney RP.

Full Text: http://sci-hub.cc/10.2105/AJPH.2014.302034

We examined the relationship between serum 25-hydroxyvitamin D (25[OH]D) and
all-cause mortality. We searched biomedical databases for articles that assessed
2 or more categories of 25(OH)D from January 1, 1966, to January 15, 2013. We
identified 32 studies and pooled the data. The hazard ratio for all-cause
mortality comparing the lowest (0-9 nanograms per milliliter [ng/mL]) to the
highest (> 30 ng/mL) category of 25(OH)D was 1.9 (95% confidence interval = 1.6,
2.2; P < .001). Serum 25(OH)D concentrations less than or equal to 30 ng/mL were
associated with higher all-cause mortality than concentrations greater than 30
ng/mL (P < .01). Our findings agree with a National Academy of Sciences report,
except the cutoff point for all-cause mortality reduction in this analysis was
greater than 30 ng/mL rather than greater than 20 ng/mL.

DOI: 10.2105/AJPH.2014.302034
PMID: 24922127

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JR,

 

Hi, and sorry to ignore your post. Welcome to the CR Forums! I hope you'll stick around and continue posting. If you plan to, would you mind registering rather than posting as guest?

 

In particular there is some speculation that solar UV exposure causes NO production in the skin which results in improved circulatory health and possibly other benefits.  For one example of many see the TED talk:

 

http://www.ted.com/talks/richard_weller_could_the_sun_be_good_for_your_heart

 

Is there evidence which indicates whether NO production by sunlight exposure is responsible for all/some of/none of the link seen  between vitamin D levels and health?

 

Yes, there certainly is evidence that sun exposure boosts Nitric Oxide (NO) levels in the blood, and that this can have benefits independent of the link between vitamin D (from sun or supplements) and health. In fact, today's video from Dr. Greger (embedded below) discusses that very topic, and points to a multitude of studies (including [1-4]) showing the benefits of increased nitric oxide, particularly for cardiovascular health. In fact, Dr. Greger highlights how sunlight exposure can convert the nitrates in foods like beets and arugula into heart-healthy nitric oxide.

 

For those of you who (like me) are fans of brown adipose tissue, nitrate-rich foods and nitric oxide cause white adipose tissue to shift to thermogenic brown/beige adipose tissue, as discussed here

 

But it seems this benefit of sun exposure is independent of the benefits of vitamin D, since sufficient circulating vitamin D is associated with lower mortality even in populations living in northern climates where the body is unable to produce vitamin D (or nitric oxide) from sun exposure.

 

Final note - in the video Dr. Greger points to the opioid-related addictive nature of tanning, and recommends against getting too much sun exposure due to it's obvious cancer-causing and skin-aging UV rays.

 

--Dean

 

 

---------

[1] C Opländer, C M Volkmar, A Paunel-Görgülü, E E van Faassen, C Heiss, M Kelm, D Halmer, M Mürtz, N Pallua, C V Suschek. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res. 2009 Nov 6;105(10):1031-40.

[2] M Mowbray, S McLintock, R Weerakoon, N Lomatschinsky, S Jones, A G Rossi, R B Weller. Enzyme-independent NO stores in human skin: quantification and influence of UV radiation. J Invest Dermatol. 2009 Apr;129(4):834-42.

[3] C Opländer, C V Suschek. New aspects of nitrite homeostasis in human skin. J Invest Dermatol. 2009 Apr;129(4):820-2.

[4] M Feelisch, V Kolb-Bachofen, D Liu, J O Lundberg, L P Revelo, C V Suschek, R B Weller. Is sunlight good for our heart? Eur Heart J. 2010 May;31(9):1041-5.

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Hi Dr. Bennet!

Like you and Todd, I take 5,000 IU daily, and my blood levels are excellent (tested twice per year).

I agree strongly with both of you and Dean, that your blood levels should be your guide I determining the out to supplement (rather than a guru's opinion, or someone's equations).

-- Saul

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Has anyone come across any data that indicates how long vitamin D stays stored in the body? The reason I ask, is that I live at 54' latitude, which means i'm only able to obtain sufficient vitamin D from the sun from about April-mid October.  In the summer I usually get a fair bit of sun (say 15 min daily full body wearing only shorts + 30 min daily on arms/legs/face), and then don't start supplementing until mid December, since I believe my vitamin D stores will last for a while.

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  • 2 months later...

I had a phone call from my doctor after getting a bunch of blood tests done. First time I've measured my vitamin D levels....

 

My 25(OH)D level came back 504! nmol/L which is around 200 ng/ml

 

Deficient: 0-40 ng/ml (0-100 nmol/l)

Sufficient: 40-80 ng/ml (100-200 nmol/l)

High Normal: 80-100 ng/ml (200-250 nmol/l)

Undesirable: > 100 ng/ml (> 250 nmol/l)

Toxic: > 150 ng/ml (> 375 nmol/l)

https://www.vitamindcouncil.org/further-topics/for-health-professionals-position-statement-on-supplementation-blood-levels-and-sun-exposure/

 

I had been taking 5000 IU gel caps (Now foods) as I went months without taking vitamin D.  Figured I was probably low because I work from home so I barely get any sunlight. About 2 months ago I took some big doses to boost my levels quickly, around 50,000 IU in total per week, for maybe 2-3 weeks, and then lowered it to 5,000 a day, maybe sometimes 10,000. For the last month though though I have just been just getting 1000 IU a day....

 

No symptoms of hypercalcemia, and level came back normal. I am surprised that it got so high though.

 

Vitamin D intake and toxicity 

 

https://youtu.be/emjCzaHtSrg?t=30m8s

 

Eek!! Today was a good reminder to be careful with supplements and actually get tested! Which i have been a little lazy about recently D: The video says much higher doses are needed to reach the level I got to? :/ I'm really surprised.

Edited by Matt
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I got my blood test results printed out (now posted on blog) and my 25(OH)D was actually 304!  I repeated it back to him when he said 504... Looks like he just glanced at it and never read it correctly....  Still pretty high, so I'll continue to let it go down. My other results were also kind of interesting... I definitely will be paying more close attention now to my diet and more frequently getting blood results (even if I have to pay privately).

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