By Thomas DeLauer

What is vitamin D? Does it play a critical role in your immune system? Here’s what science has to say! Watch as HYLETE Community Captain, Thomas DeLauer explains why vitamin D may play a bigger role than we think.

Watch Thomas DeLauer's other most recent video, to learn more about vegan deficiencies.

About Thomas DeLauer
From 280 lbs. to the magazine covers... All by living a lifestyle that is honest and real. Thomas DeLauer brings nutrition expertise along with a unique perspective on health and wellness that is everything HYLETE.

The following is a transcription of the above video:
You have vitamin D receptors everywhere, all over your body, whether it's going to be in your brain, whether it's going to be in different organs, whether it's going to be in your immune system or in your intestinal tract. Vitamin D is not even a vitamin. It's a hormone, and it plays a critical role, so whether you're supplementing or not, your vitamin D levels are something that you should be very, very aware of because now, scientists starting to show that they have more of an effect than just the small things we thought even five or six years ago. They could be a catalyst to so many different things that are wrong or powerful within our bodies.

All right, so what I want to talk about today is specifically vitamin D and its effect on not only the immune system, but more specifically, the gut itself and even our gut biome. You see, because we have vitamin D receptors within our gut, it means that we have a tight correlation between vitamin D levels and our immune system and how it affects our gut. What we are starting to find now is that vitamin D modulates what is called T-cell antigen receptors within our gut.

You may not know this, but a lot of our immune system is in our gut, and if the receptors for vitamin D are connected to T-cell antigen receptors in our gut, that means that consequently, vitamin D levels directly affect our ability to produce T-cells. Let me give you a quick background on what T-cells are.

T-cells are a big part of the immune system. When we have an infection or we have something come in our body that's a foreign invader, we have T1 and T2 cells. T1 cells go around, and they label those infections or they label those foreign bodies as bad so that T2 cells can go through and do the right rigmarole to create antibodies or get rid of them or whatever has to be done. If we have a correlation between our vitamin D receptors and how they are triggered in our actual T-cell development specifically within our gut, we can affect what is called a leaky gut.

Now, beyond just a leaky gut, there's new evidence that's starting to show that proper T-cell function and proper vitamin D levels can actually contribute to proper bacterial colonization within the gut. That's a whole different ball game. Now, that might have something to do with the fact that without a leaky gut, we're able to maintain the proper homeostasis of the gram-positive and gram-negative bacteria within our gut, but again, that's a story for a different day. I digress.

Let's talk about specifically what happens with a leaky gut. Now, a leaky gut is kind of a markety term. You hear Dr. Axe, you hear all these guys talk a leaky gut and trying to sell you products based on it. The reality is, it's a little bit more complex than just having a gut that's leaking stuff into your body. A leaky gut realistically is just inflammation within the gut. All it means is that you have this inflammation, and it's contributing to a breakup of the mucosal layer, which means that larger particles of nutrients and food can get into your bloodstream. What this ultimately can link to is systemic inflammation. It's a little bit of a stretch, but it still does make sense. If we have bigger food particles going into the body, the body has to trigger the immune system because it doesn't quite know what they are, and thus begins the T1, T2, T-cell helper system and all of that.

If we have a leaky gut, the immune system is really attacking that in a bad way, making it worse, causing more inflammation. Immune system equals inflammation. Not always good. Not always bad. In this particular case, when we find that vitamin D actually affects T-cell antigen receptors, it means that we're able to activate T1 cells. When we activate T1 cells within the gut, it means that our body is able to label the right infection and the right inflammation in our gut, consequently potentially healing the leaky gut, so therefore, reducing chronic inflammation throughout the rest of the body. It's all going to make sense in a study that I'm going to reference right now.

This study was published in the United European Gastroenterology Journal. What they did is they took 27 patients who had Crohn's disease but then they've been in remission for an extended period of time, so they probably still had some damage to their overall gut. In fact, because the inflammation was there from the Crohn's disease to begin with, they probably had a continuation of damage occurring to the gut.

What they did is they gave part of the group a 2,000 IU supplement of vitamin D. Another part of the group, they gave a placebo to. What they found is that those that took the vitamin D were very much more likely to be able to maintain their gut mucosal layer versus those that took placebo. Those that had Crohn's disease and had this chronic issue of a leaky gut going on that didn't take vitamin D had a continued immune response that continued to make their gut bacteria, their gut biome, and their gut mucosal layer totally out of wack. We're finding that even though we don't know the full reason why, we're starting to understand that vitamin D as a hormone does have that strong correlation with the immune system, specifically in the gut.

But it gets even better. They also found that those that took the vitamin D supplement had an overall reduction in C-reactive protein overall. C-reactive protein is our main modulator of inflammation, it's our main indicator inflammation, rather, so when we have high levels of CRP, it means that something's awry, something's going on, and CRP level's reduced, it means that more than likely, in this given instance, the gut is healing, and you're having less larger chunks of nutrients getting into the bloodstream, therefore, not activating the immune system, not activating the inflammation response, not activating tumor necrosis, 1-alpha, interleukin-10, interleukin-15, and of course, triggering the almighty C-reactive protein.

In short, keep your vitamin D levels in check. Whether you have to supplement or get some sunshine, you need to know your body. You need to get the blood work to see. If your doctor says you have low vitamin D, you might need to do something about it. If you think you have low vitamin D, you might need to do something about it.