Vitamin D's Role in Muscle vs. Fat — Full Breakdown & Transcript

[00:00] Can vitamin D increase muscle mass and decrease fat mass? Well, a new review paper highlights the under-recognized aspects of vitamin D when it comes to metabolic health, inhibiting myostatin, as well as affecting leptin signatures.

[00:13] This is a really interesting paper that was published in 2024 titled High-Dose Dietary Vitamin D Allocates Surplus Calories to Muscle and Growth Instead of Fat via Modulation of Myostatin and Leptin Signaling.

[00:26] I think this is really interesting. I love all things related to vitamin D. It's been something that I've been very curious about since my mentor, Joao Guillory, in 2007, told me that, and this was in Denver, Colorado,

[00:40] he started to test every single patient after going to a Michael Hullick seminar. Michael Hullick, I think he's at Mass General or Boston Children's or some such thing. He's done a lot of research in the realm of vitamin D. He went to a conference that he gave, and some of his research studies were really interesting.

[00:56] This is how we figured out that sun exposure between October and March was insufficient to induce cutaneous synthesis of vitamin D. He had medical students stand on the roof of a hospital and tan during the winter, and their vitamin D levels didn't budge.

[01:09] And so we started to learn all about vitamin D. But anyway, I got really curious about vitamin D because my mentor was really into it, and he had a clinical practice very busy. He started testing every patient. For those of you that aren't familiar with Colorado, there's over 300 sunny days per year.

[01:23] and he was just astounded that many patients who were taking vitamins and living a healthy life, some of them recreational athletes, outdoors, during the winter their levels just sucked when it came to vitamin D. And he would get their levels up and they reported all of these benefits.

[01:36] Their blood pressure went down. Oftentimes their metabolic health and blood glucose improved. Their mood improved. Their sleep improved. And he was like, whoa, as a mainstream internal medicine doctor, a vitamin can cause all these parameters that clinically I'm dealing with to improve.

[01:50] Let's get people on vitamin D. So he was recommending 4,000 to 6,000 IUs of vitamin D and receiving a lot of clinical benefit. And I was seeing his patients from a nutritional standpoint kind of helping the practice.

[02:02] And so I've been a big fan of vitamin D now for almost 20 years. But it turns out that vitamin D does affect leptin and myostatin. So myostatin is involved in the catabolism of muscle.

[02:15] I'm not an expert when it comes to myostatin. I know a lot more about leptin than myostatin. But the investigators say it's been long known that vitamin D causes muscle weakness when there's low levels,

[02:27] and that is relieved by replenishing vitamin D. Animal models to date have primarily examined vitamin D signaling and effects through experimental models of deficiency. Specifically, investigators have used approaches on limiting dietary vitamin D or conventional and or tissue knockout of the vitamin D receptor,

[02:46] and they have found that that affects muscle function. and that has led us to myostatin. It turns out that vitamin D knockout mice have very low serum leptin levels and have excess production of myostatin mRNA.

[03:02] So it turns out that myostatin can inhibit muscle growth. And so this led to the speculation that replenishing vitamin D when people have low levels can inhibit myostatin and affect leptin signaling

[03:16] And so there's some amazing images that I'm going to overlay here as we sort of talk more about this. Now, this is not a randomized clinical trial. This is a narrative review with some animal model mechanistic studies and things that I think is really interesting.

[03:28] But in conclusion, the investigators say, we report for the first time that high-dose dietary vitamin D preferentially allocates excess calories to muscle and growth instead of storing them as fat by decreasing myostatin signaling and increasing leptin production and sensitivity.

[03:45] These results provide evidence to update the conventional model of energy sensing to a new model of energy balance sensing, where integration of leptin and myostatinsincerin allow control of calorie allocation,

[03:57] which I think is just incredibly fascinating. So, let's focus on high-dose vitamin D. And first, just pause. And I want to say thank you for being here. If you're enjoying the content, hit that like button.

[04:09] Be sure to leave a comment in the comment section below. I will link this article in the description below, also in the description, will be a link to our sister company, MyoScience. So if you want to get one of the best vitamin D3 and K2 products on the market,

[04:21] also paired with vitamin A, it turns out that the vitamin D receptor is approximately close to the vitamin A receptor. The co-activation of the two enhances the health benefits more so than using them in isolation.

[04:34] So vitamin D and vitamin A are actually found together in foods. Think about like hot liver oil or even various dairy products and things like that. You often find both of them together, and that's for a reason. There's pretty good evidence to suggest that you should marry and be taking the two together.

[04:49] And we know that vitamin K is so important for affecting calcification, preventing calcification in soft tissue, making sure that calcium goes into bone and beyond. So that's why you often see these three things paired together.

[05:02] That is vitamin D, vitamin A, and vitamin K2. And myofasciense makes an awesome foreign drug. It's very affordable. You can save it to go to podcast at checkout. I'll put links in the description below. Well, in this particular study, they found that increased vitamin D inhibits myostatin production, as I mentioned.

[05:21] So myostatin is a protein that can slow down muscle protein synthesis. I know it has myo, so it sounds kind of cool and so forth, but myostatin is not something that you really want to have elevated.

[05:35] We've all seen pictures of the bowl on the Internet. There's this bull that was genetically found to have like no myostatin, very muscular. And there's been some very infrequent cases of humans who have a myostatin polymorphism in their gene.

[05:50] So have really low myostatin levels. And these are these kids that are excessively muscular. They look like they're on steroids. That's because they have low levels of myostatin. So it turns out that increased vitamin D, like super physiologic vitamin D, may inhibit myostatin production, which is a good thing.

[06:06] Now again this is an animal model analysis but they also found in this animal model study that normalizing vitamin D levels improves leptin generation per pound of fat mass and it affects and increases leptin sensitivity which is really important so let talk about leptin why do you care about leptin well leptin as you know is about 95

[06:27] of it is released from adipocytes or fat cells and it serves to tell your hypothalamus that you have enough energy on board but when individuals are leptin resistant they almost it's kind of

[06:39] like being insulin resistant right where insulin doesn't work and so it's hard to maintain normal glucose levels. Well, leptin is kind of the same thing, but leptin levels are super physiologic, over 29 nanograms per ml. That's when we start to see leptin resistance. And so people have

[06:55] excessive amounts of fat, but they're chronically hungry because these satiety pathways are skewed. Even more about leptin is it's also a pleiotropic adipocytokine. What does that really mean? Well,

[07:07] leptin not only affects energy sensing and satiety, but it promotes a unique shift in your immune system to make your immune system more chronically inflamed and so that's why we see people with lupus and multiple sclerosis and allergies and atopy and asthma they generally

[07:20] have high levels of leptin and so that's why losing body fat can actually reduce the inflammation in your body because you're becoming more leptin sensitive and leptin skews your immune system i wrote a whole book on this if you care i'm not promoting that it was over 10 years old but it's

[07:34] called belly fat effect if you're interested so leptin sensitivity is really important and it Turns out that vitamin D, super physiologic vitamin D, at least per animal model studies, might improve retin sensitivity, which is really interesting because we've known that

[07:47] vitamin D can increase a specific type of T cell in your body known as the T regulatory cell. And the T regulatory cell can help decrease chronic inflammation by shifting the tone

[07:59] in your immune system. You know that different probiotics also increase the T regulatory cell. And that's why there's a lot of therapeutics now that are targeting this T-regatory cell. And one cytokine that shifts the cells is known as interleukin-10.

[08:14] It turns out that lactobacillus plantarum, bifidobacterium, different probiotics that you can get from eating kefir or fermented milk products, even like yogurt or different probiotic supplements can increase interleukin-10.

[08:27] That can affect the T-reg cell in a favorable manner. and most importantly, exercise and not having excessive amounts of body fat can also affect the Treg cell. But it turns out that, guess what, that having super physiologic levels of vitamin D can affect leptin sensitivity,

[08:44] which, you know, is good from an appetite perspective, but it's also good for decreasing chronic inflammation. So let's go to some of the summary and findings here. Our results in mice to this point suggested to a model

[08:57] where myostatin was not simply playing a homostatic role in muscle alone, but was also conveying nutrient needs centrally. They say that is myostatin conveys not just how much energy is being used, but what the energy needs are likely to be.

[09:12] If we were to use the metaphor of the muscles as an engine, then myostatin conveys not just how much gas the engine is consuming minute to minute, but how large the engine is. I mean, this is really interesting. this model would predict that high D needed inhibition that is high vitamin D needed inhibition of myostatin and increases in leptin ceiling would not only increase energy expenditure but would also facilitate increased growth

[09:36] This is awesome. Like if you're going to have someone in a surplus, like most Americans are having potato chips and Cheez-Its and all kinds of junk food and things like that, at least maybe shunt those calories to grow muscles and not just grow fat cells.

[09:50] They say, to examine this possibility, we measure lengths of anesthetized mice from our diet groups. As we hypothesized based on this model, high vitamin D increases nose-to-tail and nose-to-rump length in mice.

[10:02] This result is consistent with vitamin D facilitating increased central energy sensing across modalities for allocation to muscle as well as for use in linear growth. This reminds me to remind you, if you have children, especially this time of year because they're not going out in the sun,

[10:19] at least in North America, make sure that they are also taking vitamin D above what the American Academy of Pediatrics says of 400 IUs of vitamin D, which is far too low to be considered optimal, especially for growing children who are laying down bone and heart tissue and things like that.

[10:37] So for your children, I do recommend minimum of 2,000 IUs of vitamin D. So that's something to consider. There's liquid formats. You can put it in yogurt or smoothies. I'm never going to know. It's virtually tasteless.

[10:49] So tasteless. So vitamin D is really important. But what I want to do is go to the discussion of this paper. Again, this is just really interesting. Now, of course, there's limitations here. This was conducted in animal models.

[11:01] We need human clinical studies to corroborate the findings from this animal model study. But I think it's important. The investigators say, Replenishing vitamin D to normal decreased myostatin production, but further increases of vitamin D did not alter serum myostatin.

[11:16] And measuring leptin concentration across dietary groups revealed that replenishment of vitamin D to normal increased the amount of leptin produced per fat mass, while high-dose vitamin D increased sensitivity to leptin. And so there's a great figure here, figure four.

[11:30] I think this is awesome. I think there's really not much of a downside to super physiologic levels of vitamin D. You know, 65 plus nanograms per ml, I think, is a great target point for most people.

[11:45] especially during cold and flu season you know I have several clients that get their levels up to 100 we do just want to watch for elevated levels of calcium the hypercalciuria in the blood that can be problematic so as long as calcium is you know not higher than 9.5 I can't remember the

[12:02] units or threshold of serum calcium here in North America but you know under 10 I think we're probably good but also make sure that if you you are doing super physiologic levels of vitamin D to pair that with K2 to ensure that if your calcium does get elevated,

[12:16] you're depositing calcium into the bone and affecting those so-called matrix CLA proteins that vitamin K2 works on. So in sum, in conclusion, in summary, it seems that superphysiologic vitamin D can help shunt calories and energy

[12:30] to preferentially make muscle and not form new fat, and it can also improve leptin sensitivity. So I appreciate you tuning all the way in. Thanks for watching this video, and we'll catch you on a future one down the road.