Hey everyone, welcome to a sneak peek ask me anything or AMA episode of the drive podcast. I'm your host Peter attia at the end of this short episode. I'll explain how you can access the AMA episodes in full along with a ton of other membership benefits. We've created or you can learn more now by going to Peter attia md.com subscribe. So without further delay, here's today's sneak peek of the ask me anything episode
Peter. Welcome to another AMA. How you doing?
I'm doing well. I noticed you're in a a new environment today.
Yeah, just always keeping you on your toes always got to switch it up. You would be happy that there's still a race car theme even in this new environment.
I noticed that right away.
I'm sure you did. So today's AMA we're going to focus on something that we haven't really covered before but we see a lot of questions come through which is related to iron iron deficiency. Feritin. This is something that people see on blood tests and they're kind of curious of like what this means. Why does it matter all of that? So we gathered all these questions and the hope is we'll cover why is iron necessary in the body what happens if you're deficient. What are those symptoms how prevalent is it? Who is most susceptible and then ultimately really lean into what can someone do about this. And is there even any concern if you have too much iron, so I think it will be really interesting for a lot of people but before we get started anything on that you want to say
No, I think this is kind of 1 of those weird topics where I just didn't learn this in med school or I didn't pay attention to it. And in residency, I don't know. I just didn't know much about what was going on. So this has been something that I have learned about only in the last few years. I would say and I think it's a far more complicated topic than we're going to cover today. And that's by Design the way we prepare for these amas is obviously very involved just in case people think I'm not just sitting up here talking off the top of my head. There's a lot of prep that goes into this but as we got down the rabbit hole of iron biology, it was like the most overwhelming thing I've ever encountered at least for me and I realized that we needed to bring it way back to make it more actionable and I think we've struck that balance here today. So there might be some people who say oh my God, you didn't get into this carrier protein and that carrier protein and and I think what we really want to do is make sure that after the end of
Listening to this you can look at your blood test. First of all, you know, what blood tests you should get and you can ask for them. If you're not getting them, you know how to look at it and interpret it and you know what to do about it. That's basically what we're trying to accomplish here and I hope we I guess people will be the judge if we can accomplish that before we get an
iron too. I think what we also did for this AMA was snag a few questions that we've seen come through and really high volume based on previous content. This will look at do you take creatine? Do you worry about the sodium in your venison sticks a few other questions that we've seen come through a lot that will also tack on at the end of this. But before we get to those when we look at iron, I think it'd be really helpful to start with helping people understand why is iron so necessary in the body and why is this something that people should think about
yeah, I was a little bit surprised to kind of learn the ubiquity of iron in the human body. So basically 2% of the human
Human Genome encodes for iron related proteins that's a staggering amount of our human genome and of these nearly half are heme binding proteins. So as we get into this and you start to understand, okay. Well, what is it about iron? That's important in the body. Well a big part of it comes down to all things related to hemoglobin and oxygen binding and oxygen transport.
Another big part of it is basically every enzyme in the body. In fact, 6.5% of all enzymes in the human body are iron dependent. And again, let's remind people what an enzyme is an enzyme is a substance that facilitates a chemical reaction. So if you think about the literally trillions of chemical reactions that are going on inside of our body imagine how many of them are facilitated by enzymes that depend on iron so we could get into more detail, but I think that's the high level of it. I mean we could literally spend the entire AMA just talking about what's going on in the mitochondria in the endoplasmic reticulum with respect to iron and how it feeds into aerobic metabolism. But I think honestly for the sake of getting to what's more actionable, I'll let people refer to the show notes where they can maybe get a little bit more detail on what's happening with iron, but if you forget everything else about iron's importance, just remember this you're not going to be able to move oxygen around your body without it and when it comes to your mitochondria and other very important
places in the body where cellular respiration takes place some of the most important enzymes depend on iron
Do certain tissues require iron or is it something that's necessary? Let's just say throughout the
whole body.
We had a hard time finding examples of tissues that don't require iron. So I'm positive that there is some whippersnapper listening to us that's going to send us an email and we always appreciate those emails correcting something and they'll say no actually Peter. This tissue does not depend on iron and so that's great. But the fact that after a bit of searching we had a hard time finding an example of a tissue that didn't require iron tells you just how important it is and as we're going to talk about especially as we get into like how do you measure iron levels and stuff a very important protein is going to come up over and over again, and it's so important that I need to just introduce it now that protein is called feritin.
And if you've ever had at least a reasonably comprehensive blood test where they've checked more than just your iron level. Hopefully you've noticed that they've checked your feritin level and take-home message number 1 of this podcast is if your doctors are not checking your feritin levels, please ask that they do it's not enough to just know what your iron level is. You have to know what that feritin level is as well. So this is a very very ubiquitous protein. I might be the only 1 that thinks of it this way but I think of it as a analogous to a like a protein, right so it's a huge spherical protein huge being relative of course and its purpose is to store iron and it stores iron to the tune of about 4500 iron ions fit within 1 inch the purpose of lipoproteins is not really to store cholesterol, but really to transport them and in the case of feritin, it's really more about storage and there's a little bit of trans.
Port most feritin actually resides within tissues namely the muscle and the liver but a small amount of feritin is obviously found in the serum and that's how we sample it. So that's why when you go and get a blood test and we'll talk more about the blood tests later 1 of the things you look at is feritin. And of course, it's measuring the concentration of feritin. It's a very important point. I want to make here before we go any further and that is that feritin is also what is known as an acute phase reactant and what that means is anytime in inflammation is present in the body. You will see feritin levels rise and they will rise independent of iron levels. So if I didn't say so earlier, I should have feritin being the total body store of iron the most dominant protein that speaks to total body iron stores when it is high all things being equal iron levels are high and when it is low the converse of that is the case, but when a person has an infection, for example, their ferritin level can be high even if they are deficient in iron,
Similarly, if a person is chronic inflammation, their feritin level will be elevated as will other acute phase reactants such as C-reactive protein, even while total body stores of iron remain low. And so therefore you have to be a bit more nuanced in your appreciation for how to measure total body iron stores which again we'll talk about so that you can not be fooled or misled by high or low levels of feritin
Peter. I know 1 of our analysts pulled an image here and I think sometimes when we're talking about some complex things it might be helpful. So I'm going to pull it up. So I think people can then start to see what you're talking about here. Yeah, Sam
pulled this figure, which I like a lot anybody who has studied iron will appreciate that. This is a profound oversimplification of the system. But truthfully, even when I look at really rigorous figures that try to communicate the complete and total Nuance of iron metabolism. I end up walking away not understanding anything so I don't think it's necessary for the purpose of our discussion to get
Get that much more complicated than this. So we consume about 10 to 20 milligrams of iron per day. Our absorption of that is roughly 10% So we're going to absorb somewhere between 1 and 2 milligrams of iron per day. The rest of it will be lost. It's going to come right out our GI system.
We're also going to lose 1 to 2 milligrams of iron per day primarily through desquamation of epithelial cells.
So if you do the math on that, you're an iron balance, if you're being 1 to 2 milligrams net per day relative to the 1 to 2 milligrams that you're losing per day. So for that person who is an iron balance, we will ask the question. Now. Where does that iron reside? Where does that iron go that you absorb and basically as you can see in this figure 3/4 of that goes into haematopoiesis meaning it goes into the production of red blood cells. It becomes the central piece of the heme molecule that sits within hemoglobin the protein that holds hemoglobin that holds hem and that transports oxygen and carbon dioxide for that matter 3/4 of it resides within those stores the other 10 to 20% Then will be put into a long-term storage Depot. That's the feritin that we spoke about and again, most of the feritin is going to be in the liver and in the heart and then the remaining call it 5 to
15% goes into these other processes that we've spoken about. So again, just remember you're going to consume 10 to 20 milligrams of iron, you'll only absorb 10% of that which will perfectly offset that which you're losing and of that amount that you absorb you put 75% of it right into the production of red blood cells 10 to 20% of that you put in the piggy bank that's called feritin and 5 to 15% of that you use for the other enzimatico.
Not water soluble and that's why they need to in the case of triglycerides be bound to either albam or inside of lipoproteins and obviously cholesterol needs to be inside lipoprotein. So the question is well gosh, if iron is water soluble, it should just be able to move willy-nilly throughout the plasma and of course, it can't because it is quite toxic So based on the fact that free Iron is toxic. It does need to be bound to another protein called transferrin and a transferrin molecule is able to hold exactly to iron ions. And that is primarily the means in which iron makes its way through the circulation and that's how transport of iron is facilitated to cells. So a cell will have a transferrin receptor that transferrin receptor acts as the baseball glove to which the baseball of transferrin with its 2 iron ions will bind and that gets basic
basically, you know absorbed into the cell through a vesicle and then it gets Incorporated to all the uses that it needs. So this figure really shows you what's the purpose of feritin transferrin and obviously how Iron moves
between them?
Peter you hinted at it earlier too and I think it'd be helpful at this point to just really lay into this which is if people are wondering what can they do and what is the best way to get tested to determine if they have sufficient iron if they're iron deficient? How would they know how to do that? And then how can they also interpret those results?
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