Vitamin D and Your Gut
Some patients take vitamin D but their levels never seem to rise, or not very much.
“Vitamin D sufficiency” is not as easy as spending a bit of regular time in the sun or swallowing pills.
Vitamin D needs to be “activated” in a two-step process, in the liver and kidneys.
But there’s more.
It is also linked to your gut biome make-up.
Vitamin D - A Pro-Hormone
This is important to understand as vitamin D, as a pro-hormone, is being linked to more and more protective actions from helping the immune system “see” cancer cells, especially breast cancer cells, to even protecting against COVID.
One of my favorite institutions, the University of California in San Diego did a deep dive on the connection between gut bacteria and vitamin D levels in your blood.
University of California San Diego researchers and collaborators recently demonstrated in older men that the makeup of a person's gut microbiome is linked to their levels of “active vitamin D”.
Vitamin D can take several different forms, but the standard blood tests most often run... detect only one, an inactive precursor that can be stored by the body.
To use vitamin D, the body must metabolize the precursor into an active form.
They found that “microbiome diversity” -- the variety of bacteria types in a person's gut -- was closely associated with active vitamin D, not the precursor form.
Greater gut microbiome diversity is thought to be associated with better health in general.
Low Vitamin D Levels
Multiple studies have suggested that people with low vitamin D levels are at higher risk for cancer, heart disease, worse COVID-19 infections and other diseases.
But realize that the largest randomized clinical trial to date, with more than 25,000 adults, concluded that taking vitamin D supplements has no effect on health outcomes, including heart disease, cancer, or even bone health.
This study suggests that this might be because these studies measured only the” precursor” form of vitamin D, rather than the active hormone (1,25-dihydroxycholecalciferol).
Active Vitamin D Levels
In addition to discovering a link between active vitamin D and overall microbiome diversity, the researchers also noted that 12 particular types of bacteria appeared more often in the gut microbiomes of men with lots of active vitamin D. Most of those 12 bacteria produce butyrate, a beneficial fatty acid that helps maintain gut lining health.
It may well be that if you can’t seem to bring up your active vitamin D levels, taking butyrate, or resistant starch like raw green banana flour and potato flour, may help boost vitamin D levels.
Because they live in different regions of the U.S., the men in the study are exposed to differing amounts of sunlight, a source of vitamin D. As expected, men who lived in San Diego, California got the most sun, and they also had the most precursor form of vitamin D.
But the team unexpectedly found no correlations between where men lived and their levels of active vitamin D hormone.
This may explain the older study of Hawaii surfers that spent many hours in the sun without sunscreen and still had surprisingly low levels of vitamin D in their blood.
It seems like it doesn't matter how much vitamin D you get through sunlight or supplementation, nor how much your body can store.
It matters how well your body is able to metabolize sunlight or supplements into “active vitamin D”.
There is also research to show that Vitamin D is a contributor to gut microbial diversity so this may be a cross-talk that works in either direction.
Nothing means anything unless you have the "bigger picture".
That is what the wise nutritionally oriented practitioner, and/or human being, strives to do: appreciate the bigger picture: what am I not seeing that is contributing to what I am seeing? That is the question.
Dr. B.
(This was originally posted in the Smart+Heart Private group on December 1, 2020)
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Reference:
Vitamin D metabolites and the gut microbiome in older men. Nature Communications, 2020; 11 (1)
Wow wow, or at least a mmm, .. 'it matters how well your body is able to metabolize .....”.. the much-lauded mighty Vit D, ....really?! Am I overreading it or is this a pretty big 'subject to? Appears to me a 'Fix' = (smarts of dedicated experts like Dr Devaki) + (trial/patience)+ (patient effort/commitment) + (regular testing) before we can conclude the thesis of what a supplements offers is proven.