A nourished microbiome offers critical protection

It’s important to pay attention to (and nourish) your microbiome for various health reasons. Not only does good gut health help combat depression, low mood, and anxietybut now, a new study shows it may help keep your levels of vitamin D in check, too. 

And given vitamin D’s vital role in combatting COVID-19—and with sunshine in short supply until summer—I think it’s safe to say this is a benefit we can all get behind 

Diversity makes the difference 

Researchers at the University of California San Diego recently found that a person’s microbiome makeup is directly linked to their levels of active vitamin D.  

Of course, there are several forms of vitamin D in your body. Your standard blood screen tests for the inactive form—which is only useful if your body can metabolize it into a an active, usable form 

And guess what? It seems your gut bacteria play a key role in this vitamin D metabolism. In addition, more diverse microbiomes, with a greater variety of friendly flora, also happen to be linked with higher levels of usable, active vitamin D.   

The researchers looked at stool and blood samples from more than 500 men participating in the Osteoporotic Fractures in Men (MrOS) Study Research Group. They used genetic sequencing to map bacterial populations in each stool sample, and measured a range of vitamin D metabolites in the blood. 

Results showed that, in addition to the benefits of overall microbiome diversity, a dozen specific bacterial strains were associated with higher levels of active vitamin D in this population. And most of those bacteria produced butyrate—the fatty acid I mentioned yesterday, which slashes inflammation and protects the lining of your gut. 

But here’s the really interesting part: All the men in this study lived in different parts of the United States, which means they had different levels of sunshine exposure. And as you might expect, the California men enjoyed more sunshine… and also higher levels of the precursor form of vitamin D.  

But active levels of vitamin D had no correlation to location at all… and everything to do with microbiome composition.  

In other words, it doesn’t matter how much vitamin D you soak up (or supplement with). Your body also needs a diverse bacterial population in order to actually use it.     

A two-way street 

It’s worth pointing out that this isn’t the first time vitamin D has come up in a conversation about microbiomes. 

In fact, recent studies show that just five weeks of high-dose vitamin D supplementation can significantly reduce populations of certain potentially harmful bacteria in the upper gastrointestinal (GI) tract. All while boosting the richness and diversity of beneficial flora. 

As an added bonus, research also shows that high-dose vitamin D can improve irritable bowel syndrome (IBS) symptoms.  

Clearly, this particular relationship is a two-way street. So here’s the bottom line  

You can—and should—boost your intake of vitamin D, especially now that sunshine is in short supply. As always, start by having your vitamin D 25 OH blood level checked every six months(“Optimal” levels are between 80 and 100 ng/mL.Then, I always recommend a daily dose of at least 50 mcg (2,000 IU) to 125 mcg (5,000 IU). For lower blood levels, I normally recommend 250 mcg (10,000 IU) daily.  

But remember, as this study shows, you must nourish your microbiome, too.  

That’s why I always recommend taking a good probiotic right alongside that D3 supplement—one that delivers prebiotics, probiotics, and postbiotics, plus dozen different strains of friendly flora.  

P.S. I talk more about how “normal” levels of vitamin D mean a lowered risk of COVID-19 infection—and deathؙ—by up to 16 percent when compared to “optimal” levels in the July 2020 issue of my monthly newsletter, Logical Health Alternatives (“COVID-19 UPDATE: The No. 1 nutrient you need in your coronavirus arsenal this summer [and all year long]”). Not yet a subscriber? Become one today! 


“Connection between gut bacteria and vitamin D levels.” Science Daily, 11/30/2020. (sciencedaily.com/releases/2020/11/201130131356.htm)