[0:00] Welcome, my name is Dr. Warrick Bishop. I'm a cardiologist, an author and a keynote speaker. I'm CEO of the Healthy Heart Network. I'm all about trying to help people
[0:12] Live as well as possible, for as long as possible.
[0:15] heart disease is huge in Australia.
[0:18] Every 20 minutes someone suffers a heart attack. Most of these could probably have been avoided if only we knew what to do. This podcast is all about helping you understand blood pressure, weight, cholesterol and weight.
[0:32] for better health.
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[0:41] someone you love.
[0:42] Hi, Dr. Warrick here and welcome. Thank you for joining me. Stay tuned because I'm talking about something really important today. It's the term cholesterol because when we say that, what are we really talking about? Well, is cholesterol, cholesterol, cholesterol? I hope to explain that in the next minutes. This is the Cholesterol Explained series. Stay tuned.
[1:07] There's a lot of confusion around cholesterol. As you may be aware, lots of voices talking, lots of people in the street offering an opinion. It's discussed in doctors' waiting rooms, but it's also discussed broadly.
[1:22] dinner party conversations, social media,
[1:25] What's often left out is people don't talk about exactly what
[1:30] what form of cholesterol that they're talking about. And that is critical. Cholesterol is a molecule.
[1:38] but it also is a molecule that can be linked
[1:41] to another molecule, in which case it's called an ester. In cholesterol...
[1:47] doesn't tend to exist by itself in the body. It moves around in a particle. I'd like to tell you more about that because it's really important to understanding how cholesterol is important for our health.
[1:59] So let's talk about cholesterol, the molecule.
[2:02] It's a lipid.
[2:04] That means it doesn't dissolve in water. It's an organic molecule. That means that it's not made by man. It's naturally occurring. It's got a carbon ring structure as a base. It's got basically four carbon rings. And then it's got a carbon and hydrogen set of tails and a hydroxyl group hanging off one end.
[2:28] Now you don't need to know too much about the structure.
[2:31] But it's important to understand that that molecule is a very simple molecule, and that's not what we find readily around the body.
[2:40] Where we tend to find cholesterol the molecule is within the cell membrane. Now that happens to be the case for every mammalian cell membrane or animal.
[2:52] cell membrane plants actually have a different organic molecule, which is very similar in structure to cholesterol.
[3:01] But it's different.
[3:02] So animals, cholesterol in their cell membranes to give that cell membrane integrity and to protect it.
[3:10] Plants.
[3:12] a similar molecule, but not the same.
[3:16] When we think about cholesterol in the body, one of the things it does is it
[3:22] can be the foundation or the basis of the formation of another of a number of hormones that our body produces. Things like estradiol.
[3:32] testosterone and progesterone are all related
[3:36] to the cholesterol base and are modified from that cholesterol base to the active hormone
[3:44] So we need it there.
[3:46] We also use cholesterol within formation of bile, and that circulation of bile, the digestion of fats,
[3:57] And cholesterol is important in us helping do that. So without cholesterol, we can't form bile. Without bile, we don't absorb fats. And that's a cyclical process that the body recirculates and reuses its cholesterol. Very effective, very interesting.
[4:14] So,
[4:16] Cholesterol molecule.
[4:18] We see it in the cell membrane, we see it in hormones, and it's used in bile acid production.
[4:26] Let me mention cholesterol, the ester. Now that simply means it's connected to another molecule. That other molecule is generally a fatty acid. No need to go into those today, but really important you understand that when we think about the bulk of cholesterol in the body, the bloodstream is connected to another molecule.
[4:45] the bulk of cholesterol moving around in the body, that it's a cholesterol ester that does that. It's not cholesterol, the molecule. I'm really wanting to make some distinction here so you know that the word cholesterol...
[4:59] is more complicated than what we often think.
[5:02] So cholesterol is done.
[5:05] Now I'd like to talk about
[5:08] cholesterol in the particle now the particle i'm talking about are the particles that move around in the bloodstream
[5:17] carrying our lipids. Now remember I said lipids don't dissolve in water. So if you've got something that's a lipid that doesn't dissolve in water,
[5:30] If you were to stand for long enough, then that liquid would float to the surface.
[5:36] It would float to our brain. Imagine
[5:39] cream in milk that's not being homogenized. That cream floats to the surface. Imagine oil on water. It floats...
[5:49] to the surface, so there are particles within
[5:53] our bloodstream that carry lipids and those particles they're very interesting complex balls often made of proteins that have uh phospholipids attached but basically these are like prickly little balls imagine the ferrero rocher chocolate on the inside is the chocolate on the outside of the sort of rough irregular bits well these are
[6:21] They're called lipoprotein particles because they're made up of lipids and proteins, are what carry
[6:29] cholesterol and the other fats like triglycerides around in the bloodstream.
[6:35] Very important and...
[6:38] Very interesting because then we get to talk about different particles. Now the LDL, low density lipoprotein particle, is one of those lipoprotein particles that's important and carries cholesterol fragments, cholesterol ester, importantly, around in the bloodstream.
[7:08] I mean,
[7:09] But of its own, it is not cholesterol. It is a protein structure, a protein ball with phospholipids and...
[7:19] a cargo of things like cholesterol and triglycerides. The low-density lipoprotein particle, the LDL particle, is characterized by a particular protein attached to it called APO-D100. This becomes really important because, as you're probably aware, the
[7:40] Cholesterol is more complicated than just calling it cholesterol.
[7:45] This becomes really important because one of the other
[7:49] particles that's in the bloodstream that carries cholesterol is called the HDL particle.
[7:56] And the HDL particle stands for high-density lipoprotein. So this is a smaller sample.
[8:02] denser particle. Really interesting.
[8:06] Really interesting is that this particle has a different apolipoprotein attached to it. Instead of having APO B100, it has APO 1A.
[8:17] *sniff*
[8:19] Also really interesting is the HDL particle has a very similar payload in it, so it carries...
[8:26] cholesterol ester, a little bit of cholesterol, and try to get through it just like the LDL particle, but it's not the same.
[8:34] cholesterol.
[8:36] in its different forms and the HDL particle and LDL particle behave in different ways.
[8:43] This is critical because if we understand cholesterol, we've got the molecule, the ester, the particle, which is LDL and HDL. I've explained to you that the molecule is an organic molecule that's a lipid.
[8:57] that most commonly we find it
[9:01] within the body as an ester, predominantly,
[9:05] It gets carried around in a number of different particles, but two really important ones that we measure regularly in the bloodstream are one called LDL cholesterol, low-density lipoprotein cholesterol, and HDL cholesterol, high-density lipoprotein cholesterol. Now, here's the bit that's really important. All our research tells us that it is the...
[9:32] the LDL cholesterol, which is predominantly an ester, and the cholesterol that's in the LDL particle, that's the one that is linked to potential poor outcome when it comes to cardiovascular disease. It's the one that we can lower and reduce future event of cardiovascular disease. And here's the really interesting thing. If we take the same cholesterol esters,
[10:02] put them in the high density lipoprotein particle, which is a different particle, then those problems are not seen. So cholesterol, a molecule,
[10:13] travels around the place mostly as an ester. It's a problem when it sits in the LDL particle, but it doesn't seem to be a problem when it sits in the HDL particle, and this is related to the nature of those particles.
[10:28] Have I confused you? I hope not. It's so interesting, but don't just think cholesterol is cholesterol is cholesterol. We want to know more about it. And we're really interested in cholesterol in that LDL particle.
[10:44] So I think I've explained to you what we're talking about when we talk about cholesterol. I think I've pointed out that cholesterol may not be cholesterol, may not be cholesterol, may not be cholesterol. I think I've shown you that cholesterol is not the enemy and it's the LDL particle that we're most concerned and interested about. This has been part of the
[11:13] may be beneficial for
[11:17] If you're interested, check out Cholesterol, Explain, the book I've written with my good friend and colleague, a world leader in management of cholesterol, Dr.
[11:27] Karam Kostner. For now, I wish you the very best. I hope you've got something from this.
[11:32] Take care.
[11:33] And bye for now.
[11:35] Did you know that coronary artery disease kills one in four people? So most of us are likely to carry some risk or know someone who does. If you're interested in finding out more about how to evaluate that risk
[11:50] Check out
[11:51] www.virtualheartcheck.com.au. It'll give you information about risk,
[11:59] And what else can be done to be even more precise?
