Written by Angelo

Categories: supplements

February 22 2023

The composition and function of the human gut microbiome are important in determining health and disease. Each of us harbors about 10-100 times more bacteria in our gut than the cells in our gastrointestinal tract. These gut microbes are involved in the regulation of metabolism, physiology and immune function. Since vitamin D plays a vital role in regulating calcium absorption from the gut and has also been implicated in influencing immunity, researchers hypothesized that the gut microbiome may be an important regulator of vitamin D metabolism.

I had already commented on the study here:


To test this hypothesis, they studied 567 community-dwelling elderly men representing six clinical centers in the United States who had a mean age of 84 years (SD = 4,1) and who provided stool and blood samples between 2015- 16. They performed 16S ribosomal rRNA sequencing to define suboperative taxonomic units using Deblur and Greengenes 13.8 and used LC-MSMS to quantify serum vitamin D metabolites which included 25(OH)D, 1,25(OH) 2D and 24,25(AH)2D. The mean BMI of men was 27 kg/m2, with 89% reporting their health as good/excellent. Men residing in San Diego averaged more sunny days than the other 5 sites with correspondingly higher 25(OH)D levels as expected because sun exposure is known to affect 25(OH)D.



However, they found no significant differences between sites in vitamin D active hormone (1,25(OH)2D). (Figure 1). Which means that the 25OHD3 is not the right parameter to evaluate any "deficiencies"… CORRECT???? In full agreement with what is reported and deduced in my book: VITAMIN D.

REFERENCE: https://www.nature.com/articles/s41467-020-19793-8

In the study published in 2020 in the prestigious Nature Communications, strong correlations are demonstrated between the active vitamin D hormone and microbial diversity, diversity b and 12 specific taxonomies, most of which are known producers of butyrate. Additionally, the study of measures of vitamin D flux, 1,25(OH)2D/25(OH)D hydroxylation or “activation ratio,” and vitamin D metabolic ratio 24,25(OH)2D/25 (OH)D (VMR ) or "catabolism ratio," again the researchers report significant associations with increased microbial diversity in these men.

However, surprisingly, and despite what the hormone D "experts" say, no significant associations were found between 25(OH)D and measures of gut microbial diversity or specific taxonomies.


To assess vitamin D status in humans, physicians order blood 25(OH)D levels because it is a stable measure that reflects body stores of vitamin D. However, the active vitamin D hormone is 1,25, 1 dihydroxy vitamin D (25, 2(OH)2D) binding the vitamin D receptor. The vitamin D receptor is highly expressed in the human intestine. Many large observational studies conducted around the world suggest that people with vitamin D deficiency may suffer from a multitude of adverse health outcomes such as increased cancer, cardiovascular disease, SARS-CoV-1 infection, and early mortality (4- 25.000). However, several other studies, including a recent large randomized controlled clinical trial of vitamin D supplementation in over 5 people, have shown no health benefit (XNUMX). Based on the most recent results from randomized controlled trials, perhaps the focus on vitamin D supplementation should be reevaluated with respect to a better understanding of the underlying pathophysiological mechanisms.


The consistency of results between different measures of active vitamin D and measures of vitamin D flux but not 25(OH)D in relation to measures of gut microbial diversity and butyrate-producing bacteria is remarkable. The National Academy of Medicine (formerly known as IOM) has concluded that the evidence for a threshold of optimal 25(OH)D levels should be 50 nmol/L (20 ng/mL), as this level allows for adequate absorption intestinal calcium with no increased benefit demonstrated with higher levels of vitamin D (6). Existing evidence to date supports the concept that there is a physiological range of efficacy, that more is not necessarily better, and now the study results question the utility of measuring a body storage indicator without considering the underlying physiology.


The study design was cross-sectional in nature, so researchers were unable to comment on the directionality of the strong and significant association between active vitamin D, related metabolic ratios, and gut microbial diversity or specific butyrate-producing bacteria. Regardless of directionality, however, it was shown that, in 567 elderly men,

vitamin D flux assessments are more accurate measures of biological relevance than 25(OH)D as they correlate with both vitamin D status (Figure 2)

than with gut microbiota measurements at -diversity. In addition to studying the gut microbiome, future investigations should consider measures of vitamin D flux in relation to relevant clinical outcomes. Regarding the gut microbiome, further investigations are needed to understand the cellular interactions between commensal bacteria, their metabolic products, their hosts, and vitamin D substrates in regulating vitamin D metabolism to optimize calcium absorption, immune function and perhaps even further important cell processes that remain to be discovered.

Instead the exposure to light? Sun, photobiomodulation and phototherapy????

How light improves the microbiome

And this is why our customers are delighted both with our lamps and above all with our VDR supplement which works great especially at the intestinal level, unblocking, as far as possible, the VDR (Vitamin D Receptors) allowing both greater functionality of the active form of VITAMIN D (1,25OHD3) but also (we have just seen it from the study) to obtain an IDEAL microbiome structure regardless of the diet (which is still important) and above all from other supplements sold as "miraculous". The famous probiotics that are generating space profits for their manufacturers, to no avail for the poor customers.


Reading continues below…


  1. Yin L, Ordóñez-Mena JM, Chen T, Schöttker B, Arndt V, Brenner H. Circulating 25-hydroxyvitamin D serum concentration and total cancer incidence and mortality: a systematic review and meta-analysis. Prev Med. 2013 Dec;57(6):753-64. doi: 10.1016/j.ypmed.2013.08.026. Epub 2013 Sep 10. PMID: 24036014.
  2. Wang TJ, Pencina MJ, Booth SL, Jacques PF, Ingelsson E, Lanier K, Benjamin EJ, D'Agostino RB, Wolf M, Vasan RS. Vitamin D deficiency and risk of cardiovascular disease. circulation. 2008 Jan 29;117(4):503-11 . doi: 10.1161/CIRCULATIONAHA.107.706127. Epub 2008 Jan 7. PMID: 18180395; PMC ID: PMC2726624.
  3. Meltzer DO, Best TJ, Zhang H, Vokes T, Arora V, Solway J. Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results. JAMA Network Open. 2020 Sep 1;3(9):e2019722. doi: 10.1001/jamanetworkopen.2020.19722. PMID: 32880651; PMC ID: PMC7489852.
  4. Fan Biobank. J Clin Endocrinol Metab. 2020 Oct 1;105(10):dgaa432. doi: 10.1210/clinem/dgaa432. PMID: 32620963.
  5. Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, Gibson H, Gordon D, Copeland T, D'Agostino D, Friedenberg G, Ridge C, Bubes V, Giovannucci EL, Willett WC, Buring JE; VITAL Research Group. Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease. N Engl J Med. 2019 Jan 3;380(1):33-44 . doi:10.1056/NEJMoa1809944. Epub 2018 Nov 10. PMID: 30415629; PMCID: PMC6425757.Bottom of Form
  6. Institute of Medicine. Dietary reference intakes for calcium and vitamin D. Washington, DC: National Academies Press, 2011.



I was recently sent a fifth grade article by a vitamin D "expert" who claimed that its "high dosages" could improve the structure of the precious intestinal microbiome and, consequently, improve the course of all inflammatory bowel diseases such as colitis, IBS, SIBO…

What was the article based on? Trivially on an association.
That is, deposition "levels" of the hormone were associated with better intestinal health.
The expert on duty therefore automatically deduced that by "supplementing" the D3 it was possible to solve all the problems of this world and go smoothly to the bathroom every morning, serene and peaceful.

Well, the short article inevitably collides with the reality of RCTs.

REFERENCE: https://www.nature.com/articles/s41598-018-29759-y

In this article published in NATURE, humanized guinea pigs with VITAMIN D were tested and it was seen that vitamin D supplementation, which we should rather call by its name: HORMON REPLACEMENT THERAPY (UNCONVENTIONAL)… With the equivalent of 10.000 IU of vitamin D per day, exactly as advised by the expert to whom I refer, ALTERED THE STRUCTURE OF THE MICROBIOME BUT NEGATIVELY… So the expert was half right… He forgot the second half…

Thus, high dose vitamin D supplementation is associated with a shift to a more inflammatory faecal microbiome and increased susceptibility to colitis, with a fall in circulating vitamin D occurring as a secondary event in response to the inflammatory process.

Thus, high-dose vitamin D supplementation is associated with a shift to a more inflammatory fecal microbiome and increased susceptibility to colitis, with a fall in circulating vitamin D occurring as a secondary event in response to the inflammatory process.

Attention now!!!!

The mice that exhibited colitis also saw a dramatic drop in 25OHD3 (despite HRT!!!) which shows that it is inflammation that drives the “levels” and not the other way around…


A subset of mice were exposed to UV rather than given HRT and saw REGULATION of all measured metabolites (which dropped) and no gut problems.

A dog that bites the thing… Do you understand?????


But then the "addicted" to HORMONE D arrives and exclaims: BUT I TROFOH GOODHEHHH...

Of course you're fine… The immunosuppressive effect hides the damage you're inflicting on yourself like a total moron.

And with that, that's all for today too.

Angelo Rossiello.

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