Watch Rhonda’s full appearance on The Tim Ferriss Show: https://www.youtube.com/watch?v=T2FV1Ir344A
In this video, Dr. Rhonda Patrick discusses:
• Why is vitamin D deficiency so widespread?
• Do vitamin D supplements actually contain what they say?
• What is the optimal blood level for vitamin D?
• Does magnesium deficiency cause low vitamin D?
• How much vitamin D should you actually take?
Read the FoundMyFitness topic page on Vitamin D for a deeper dive into the science:
https://www.foundmyfitness.com/topics/vitamin-d
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I want to loop back around just so people aren’t like, “Ferris, you forgot about vitamin D.” I wanted to talk about vitamin D. So, the vitamin D, I’ve taken vitamin D forever. Tend to take 5,000 IU a day. I particularly in the summer get I would say at least an hour in the sun without skin protection. And I build up to that. I’m not an idiot about it. And yet, I am barely in my labs. I’m always barely squeaking by on vitamin D. And for almost all of my adult friends who get labs, and this is also race agnostic, right? Everybody is deficient or just on the border of being deficient, even if they seem to be taking a lot of supplemental vitamin D and getting a lot of sunshine. And I have to ask myself, what the hell is going on here? In what set of circumstances is it possible that everyone would be so deficient if they seem to be getting a bunch of sunlight? They’re taking a bunch of supplemental vitamin D. Can you shed any light on this? I can. Or is there a problem with this measurement in the first place? Which is why I was talking about like proxies and confounders and stuff earlier with respect to some of the other studies. Yeah. So please please educate me the way vitamin D is measured. So vitamin D actually gets converted into a steroid hormone. And this steroid hormone essentially it’s going inside the nucleus of our cells where all of our DNA is and it’s activating 5% of the protein encoding human genome. Many of these genes it activates cloth by the way you mentioned cloth. Vitamin D is important for activating cloth. Nice. Yeah. So very hugely important for dementia risk which we we can talk about. But to sort of answer your question, so your vitamin D levels are measured by a proxy and it’s called 25 hydroxy vitamin D which is the precursor to the steroid hormone. So essentially vitamin D3 which is made in your skin or if you supplement with it exogenously gets into your bloodstream and that vitamin D3 then goes to the liver and it’s converted into 25 hydroxy vitamin D. That’s the major circulating form of vitamin D. Mhm. after it’s, you know, 25 hydroxy vitamin D is made in the liver, it then goes to the kidneys and it’s made into the actual active steroid hormone which is called 125 hydroxy vitamin D. Well, it turns out the enzymes that are doing the conversion of vitamin D3 into that stable form that everyone gets, you know, when they’re getting a vitamin D blood test, that’s what they’re looking at requires magnesium to work. And there have been studies showing that in with low magnesium, it doesn’t happen readily at all. Interesting. 50% of the US population has insufficient levels of magnesium. So, you’re talking about a coin toss here, right? One out of two. One out of two, right? Mhm. 50-50 chance a person’s not going to be getting enough magnesium. That’s been shown to actually play a role in circulating levels of vitamin D. So, there have been NHEN studies and stuff showing that people that are that have low magnesium intake also have low circulating forms of 25 hydroxy vitamin D. So, that’s one thing. Mhm. Another thing comes down to genetics. There’s actually a lot of people that have snips, very common ones that probably came from more southern latitude areas that don’t make as much vitamin D3 from the sun exposure because probably they’re getting so much sun, right? Yeah. So, essentially, there’s the genetic component as well. And I’ve seen a lot of people’s, you know, different snip makeups. And I know quite a few people that actually have to take a super high level of vitamin D3 to actually get enough vitamin D. And then the other thing is that you mentioned earlier the variation between supplements. There have been studies on vitamin D supplements and it’s the same problem with melatonin. There are some vitamin D supplements with a fraction of what is stated in terms of concentration of vitamin D3 on the nutrition facts and then some of them have like 10 times as much vitamin D. Yeah. So, there’s just like this huge variation where you’re like, it says it has 5,000 IUs, but it only has 500. There’s a lot of different factors that could be contributing to that as well. So, and then there’s also in terms of like people getting sun exposure. You said you don’t wear sunscreen. Some people do. People that have darker skin pigmentation have melanin. That’s a natural sunscreen. There have been studies showing that. For example, out of the University of Chicago, there was a study that was published a few years back showing African-Americans have to stay in the sun six to 10 times as long as a Caucasian to make the same amount of vitamin D3 from the same amount of sun exposure because they have a natural sunscreen. Yep. Melanin, which is that darker skin pigmentation. It’s a natural sunscreen. It’s also why their skin always looks great as they’re aging. You’re like, “Oh, you’re 75. Your skin looks like you’re 30.” I remember I won’t mention him by name but meeting this this African-American fellow and I thought he was like 25 and he was 53 and had like f and the way we got to that is I was like oh you are you married and he’s like yeah I have five kids and I was like wait what you have five kids you don’t look Mormon like wait what’s going on here and lo and behold let me dig into some of this real quick so recommended brands for vitamin D and how much should someone like me potentially be taking as a starting point because I’m also wary of taking too much vitamin D. I don’t want to overdose on vitamin D. It seems like there are some risks associated with that. Maybe I’m over overstating them, but how do you think about that? And then in terms of this rate limiting factor that you mentioned, magnesium, what type of magnesium? How much? How should I think about both of these? First of all, we need to talk about vitamin D levels and what the optimal levels are. And that’s really important for someone to figure out how much they should supplement with. I tend to think anywhere between 40 60 to 80. Like 40 to 80 nanogs per mill. You’re you’re in an optimal range. I like 40 to 60. I think that’s my sweet spot. And and that’s because there’s lots of studies out there showing all cause mortality is lower within that range. So, you know, if you’re with like 50 nanogs per male would be great. I mean, that’s a great place to be if you’re below, you know, 30. If you’re about just 30, you might want to try to get up to 40. Let’s just say for argument sake that I’m at 30. I think I’m probably closer to 40, but let’s say let’s say it’s 30 for someone that’s at 30 Danograms per mill is supplementing with 5,000 IUs a day. Five. Yeah. 5,000 IUs a day and getting an hour of sun in the summer without sunscreen, you probably should be closer to 50 nanogs per mill. I would say if you’re taking that, I’ll check my last labs. I just had them pulled two weeks ago, so I’ll double check. So, for someone in that case, you might go up to 7,000 IUs and check and see where you’re at a month later. Mhm. And if you then are in the 40 to 50 range, then that’s your optimal dose to take. And this is an important conversation to have Tim because it really is there’s an individual component here and people just want to at the end of the day they want to what how much do I take? How much do I take? Well, you have to get a vitamin D blood test. This is one of those that you have to really measure because as you mentioned there’s huge variation
