The evidence for targeting >/= 50 ng/ml Vitamin D sufficiency is stronger than you think.

And not just against SARS-CoV2, against all T-cell moderated infectious disease.

My goal with this inaugural post is to bring some new perspective to the discussion of Vitamin D supplementation. My modus operandi will be to first lay out the evidence I will be using to make my case, and then explain how it speaks to me. If you hear the data telling a different story, then we should discuss, as that is the essence of science.

Here is the well-known paper that first shined a spotlight on 50 ng/ml - a meta-study published in Sept. 2021;

https://www.medrxiv.org/content/10.1101/2021.09.22.21263977v1

COVID-19 mortality risk correlates inversely with vitamin D3 status, and a mortality rate close to zero could theoretically be achieved at 50 ng/ml 25(OH)D3: Results of a systematic review and meta-analysis

While this single paper, being a meta-analysis of many studies, was really enough to seal the deal regarding how much Vitamin D sufficiency is enough, we can still ask ourselves two questions: Is this just relevant to a respiratory virus? Also, if this is truly a magic number for sufficiency, can we find some tie to evolutionary biology?

Here then is the next paper I would like to read into evidence, from Feb. 2014:

https://jamanetwork.com/journals/jamasurgery/fullarticle/1782085

Title: Association Between Preoperative 25-Hydroxyvitamin D Level and Hospital-Acquired Infections Following Roux-en-Y Gastric Bypass Surgery

Results: ……Locally weighted scatter plot smoothing plots (Figure 1 and Figure 2) showed a near inverse relationship between 25(OH)D level and the risk for nosocomial infection for 25(OH)D levels around 30 ng/mL. Between 25(OH)D levels of 30 ng/mL and 50 ng/mL, there was a progressive flattening of the curve. Beyond 50 ng/mL, the curve appeared flat.

Wow.. what a coincidence! There’s that 50 ng/ml level again, this time in a paper relating tendency toward a post surgical bacterial infection to Vitamin D sufficiency. There appears to be a protective benefit to higher levels, finally leveling off at 50 ng/ml. Let’s look at the graphical depiction of this data from the paper.

I hope that the above graph is speaking to you, especially in conjunction with the Covid-19 data. The final question I asked was this; Is there evidence of an evolutionary basis for 50 ng/ml being the magic threshold for sufficiency? If humans first appeared on earth ~ 300,000 years ago in Africa, getting their Vitamin D mostly from sun exposure, is there any means by which we can determine whether or not there exist evolutionary roots to this magic number? As it turns out, the answer is yes, right here in a paper published in 2012;

https://pubmed.ncbi.nlm.nih.gov/22264449/

Title: Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l

“……Populations with traditional lifestyles having lifelong, year-round exposure to tropical sunlight might provide us with information on optimal vitamin D status from an evolutionary perspective. We measured the sum of serum 25-hydroxyvitamin D₂ and D₃ (25(OH)D) concentrations of thirty-five pastoral Maasai (34 (SD 10) years, 43 % male) and twenty-five Hadzabe hunter-gatherers (35 (SD 12) years, 84 % male) living in Tanzania.”

We only need convert the Vitamin D blood level units from the more technically oriented nmol/l back to ng/ml in order to finish telling the story. Here’s a handy conversion website;

https://www.unitslab.com/node/84

The answer is…. drumroll…… 115 nmol/liter = 46 ng/ml!!!!!!!!!!! Remember that this was a mean, with some test subjects above, and some below this value. Still, 46 ng/ml is remarkably close to the magic sufficiency numbers pointed to by the other two papers I have entered into evidence above. For the Maasai tribe, the mean was actually 119 nmol/liter = 48 ng/ml. Closer still.

The data is telling us something, but it still needs perspective. Unless a modern human is spending an inordinate amount of time in the sun, or supplementing with Vitamin D3 well beyond the RDA, almost all of us are walking around with Vitamin D (as 25-hydroxyvitamin D metabolite) levels well below this magic threshold of 50 ng/ml. Let’s look at the “before” and “after” blood level data for this study of Vitamin D supplementation as a means to reduce incidence of Covid-19 infections in Mexican front line medical workers;

https://www.sciencedirect.com/science/article/pii/S0188440922000455

Title: Efficacy and Safety of Vitamin D Supplementation to Prevent COVID-19 in Frontline Healthcare Workers. A Randomized Clinical Trial

The above placebo-controlled study tested the benefit of supplementing with 4000 IU daily for a period of 30 days, mostly during the second half of 2020. Unsurprisingly, the supplemented folks had a risk ratio of .23 for infection vs. their un-supplemented colleagues, in other words, 77% less infections. But I am not here to tell you that Vitamin D is beneficial.. you already knew that.

Instead, please focus on the “before” or basal data in both the Vitamin D and placebo groups above, because these are a pretty good representation of the average blood levels of folks living in Mexico City. Do you see anyone reaching >/= 50 ng/ml? One person in the Placebo group… out of over 300 that started the study. Only a handful in each group were above 30 ng/ml at the start of the study, and Mexico City does not lack for sun.

4000 IU per day supplementation raised the mean 25-hydroxy Vitamin D levels in the supplemented group measurably, but still only a handful reached >/= 50 ng/ml. The mean shifted from 18 ng/ml up to 26 nm/ml. Could the results have been even better with higher/longer supplementation, getting the mean closer to 50ng/ml? Likely yes. That is why I, and many others I know take 10,000 IU daily, along with co-factors Mg and Vitamin K2 MK-7. The truth is, in many developed countries, without supplementation, almost nobody is walking around with fully sufficient Vitamin D, and that is the revelation of the data presented here today.

For a one-stop Vitamin D reference I highly suggest this site that popped up early in the Covid-19 saga - it interestingly lists the actual supplementation dosages of each of the medical signatories;

https://vitamindforall.org/letter.html

Further Reading:

Many pro-health commentators have shed light on the benefits of sufficient Vitamin D, summarizing research and exposing its mechanisms of action - in particular I will point the reader to this post, the last in a series of five posts on the subject by the excellent Colleen Huber, NMD;

How much vitamin D is optimal to take? Part 5 of a series