Podcast Summary
The Role of Lipoproteins in Lipid Transportation and Atherosclerosis: Lipids in the human body rely on lipoproteins to transport them through the bloodstream and deliver them to specific locations. Understanding this role is crucial in understanding lipid-related diseases like atherosclerosis.
Lipids, such as cholesterol, in the human body cannot travel on their own. They rely on lipoproteins, which are protein-wrapped structures, to transport them through the bloodstream. This discovery was made by John Hoffman in the early fifties, who realized that lipids are hydrophobic and cannot float freely in plasma. Instead, they need to be carried by lipoproteins, with albumin being a common protein carrier. Lipids inside lipoproteins can be delivered to specific locations in the body, such as the arterial wall. Atherosclerosis, a condition characterized by the buildup of lipids in the arterial wall, occurs when lipoproteins mistakenly deliver sterols to this area. Understanding the role of lipoproteins is crucial in comprehending lipid-related diseases like atherosclerosis.
Lipoprotein density and its impact on health: The concentration of LDL particles plays a greater role in health than just their size or density. It is important to focus on overall LDL particle concentration rather than just their individual characteristics.
The density of lipoproteins, which transport fats in the body, is determined by the ratio of lipid (fat) content to protein content. The larger the lipid content, the more buoyant the lipoprotein, while the smaller and denser it becomes as it loses lipids. It is incorrect to associate small size with density within each classification of lipoproteins, as there is always a range of densities within a class. The focus should not be solely on the size or density of LDLs or HDLs, but on the overall concentration of LDL particles. Having small LDLs may require a high concentration of particles, which can have a greater impact on health than just the size or density.
The Role of Apolipoproteins in Lipoprotein Structure and Function: APO B concentration can indicate the number of lipoprotein particles present, providing valuable insight into their metabolism and overall function.
Apolipoproteins play a crucial role in determining the structure and function of lipoproteins. Lipoproteins are spherical structures with a membrane made up of phospholipids and other lipids. The apolipoprotein gives the lipoprotein its signature characteristics. Different types of lipoproteins have different apolipoproteins, such as B48, B100, and others. APO B in particular provides structural integrity to the particle and acts as the ligand for receptors that remove these particles from the plasma when they are no longer needed. Understanding the concentration of APO B can serve as a proxy for determining the number of particles present. Over time, research has identified various enzymes, receptors, and ligands involved in the metabolism of lipoproteins, leading to a better understanding of their function.
Understanding Lipid Metrics for Accurate Cholesterol Assessment: Differentiating between different types of lipoproteins, such as LDL cholesterol and LDL particle number, provides a more comprehensive understanding of cholesterol levels and associated risks.
Understanding lipid metrics is crucial for accurately assessing cholesterol levels. Total cholesterol is a measurement of the cholesterol found in all lipoproteins in the body, including chylomicrons, VLDL, intermediate density particles, LDL, and HDL. However, it does not differentiate between the different types of lipoproteins. LDL cholesterol, on the other hand, specifically measures the cholesterol carried by LDL particles, which are considered "bad" cholesterol. It is important to use proper lipid metrics and not simply refer to LDL as a laboratory metric. Differentiating between LDL cholesterol, LDL particle number, and other lipidomic factors can provide a more comprehensive understanding of cholesterol levels and associated risks.
Rethinking Total Cholesterol Levels as a Measure of Heart Disease Risk: Measuring specific cholesterol within APO B particles, such as LDL cholesterol, along with HDL cholesterol and triglyceride levels, provides a more accurate assessment of individual risk factors for heart disease.
Using total cholesterol levels as a measure of heart disease risk is not accurate. The cholesterol within the APO B particles, specifically the LDL cholesterol, is what contributes to a higher risk of atherosclerosis. In the past, total cholesterol was the only clinically measurable parameter, so it was used as a crude indicator of risk. However, later studies showed that low HDL cholesterol and high triglyceride levels were even more predictive of heart attack risk. Fortunately, with the development of direct assays, we can now measure HDL cholesterol and estimate LDL cholesterol without the need for time-consuming processes like ultra centrifugation. This allows for a more accurate assessment of individual risk factors for heart disease.
Understanding VLDL Composition for Accurate Cholesterol Analysis: Calculating LDL cholesterol by measuring triglycerides and cholesterol ratio provides a more accurate estimate, especially when triglyceride levels are high, improving assessments of cardiovascular health.
Understanding the composition of VLDL particles, particularly the ratio of triglycerides to cholesterol, can provide important insights into a person's cholesterol levels. By calculating the VLDL cholesterol and triglycerides divided by 5, one can determine their LDL cholesterol. This calculation is especially useful when triglyceride levels are elevated, as direct assays of LDL cholesterol may not be as accurate. However, it is important to note that the calculated LDL cholesterol is still a better estimate of LDL concentration than total cholesterol. Additionally, the introduction of non-HDL cholesterol and advancements in calculating LDL cholesterol have further improved correlations with APOB or LDL particle concentration. Overall, understanding lipoprotein metrics through techniques like NMR spectroscopy helps quantify lipoproteins more accurately and provides valuable information for assessing cardiovascular health.
Measuring APO B Particles for Accurate Cardiovascular Risk Assessment: Measuring APO B particles, particularly LDL particle concentration, provides a more accurate prediction of cardiovascular risk compared to measuring cholesterol alone. Consider both APO B and LDL particle counts for an accurate assessment of risk.
Measuring the number of APO B particles, specifically LDL particle concentration, is a more accurate predictor of cardiovascular risk than measuring cholesterol alone. APO B particles are responsible for delivering sterols into the artery walls, triggering an inflammatory process that leads to atherosclerosis. While cholesterol concentration can be measured directly, it is the number of particles that is more indicative of risk. VLDL particles also contribute to atherosclerosis, but the vast majority of APO B particles are LDL. A high APO B or LDL particle count, combined with high LDL cholesterol, signifies a significant risk. When there is a discrepancy between cholesterol levels and particle counts, the particle metric is a better indicator of risk. Therefore, both APO B and LDL particle counts should be measured to accurately assess cardiovascular risk.
The Importance of Knowing and Understanding Your Lipid Profile: Assessing and prioritizing LDL Particle Count (LDL P) or APO B in lipid profiles is crucial for identifying lipid-related risk and disease, despite resistance from healthcare professionals, guidelines, and payers.
Knowing and understanding one's lipid profile, specifically the LDL Particle Count (LDL P) or APO B, is crucial for assessing lipid-related risk and screening for disease. It is disconcerting that many healthcare professionals in the United States do not prioritize these important metrics, leading patients to have to argue for their inclusion in their health assessments. Public health guidelines and third-party payers, who often resist covering the costs of additional metrics, contribute to the lag in comprehensive lipid care. The internet has both helped and confused people on this topic, with some individuals choosing to deny the significance of LDL particle concentrations. However, the overwhelming literature supports the association between elevated LDL P and atherosclerosis, making it risky to ignore this metric. While there may be exceptions, it is important to prioritize LDL P/APO B assessment until a serious study presents evidence otherwise.
Understanding Cholesterol: Forms, Functions, and Health Implications.: Knowing the different forms and functions of cholesterol is important for maintaining vascular health, as it can lead to plaque build-up and affect various bodily functions.
Cholesterol is a molecule with a four-ring structure and a carbon chain tail. It plays a role in vascular health and can cause plaque build-up in arterial walls. Cholesterol exists in different forms, such as free cholesterol (FC) and cholesterol ester (CE). The hydroxy group in cholesterol is soluble in water, while the carbon chain tail is not. Cholesterol ester is a storage form of cholesterol found in fat cells, and it needs to be deesterified to be utilized for various functions, such as hormone production or bile acid synthesis. Understanding the different forms and functions of cholesterol is crucial for maintaining overall health.
Understanding the complexity of lipids and debunking misinformation found online: Learning about lipids and their functions in the body is essential for interpreting and debunking online misinformation about cholesterol and its impact on health.
Lipidology, the study of lipids, is a highly complex subject that requires a deep understanding of biochemistry. Lipids, such as cholesterol, have intricate structures and properties that significantly impact their functions in the body. One key aspect discussed is the difference between cholesterol and stannals, which are saturated versions of cholesterol. Stannals cannot be absorbed by the intestines and are excreted in the feces, making them useful markers for cholesterol absorption. Understanding the complexity of lipids is crucial for interpreting and debunking misinformation found online. It emphasizes the need for education and a solid foundation in biochemistry to comprehend the intricacies of lipid metabolism and its implications for health.
The Risks of Phytosterol Supplementation: Phytosterol supplements may not be beneficial and could be more harmful to our health than cholesterol itself. Monitoring phytosterol levels and maintaining a healthy balance of cholesterol is crucial.
Phytosterols, which are found in plants, are not necessary for our bodies to function properly. Evolution has ensured that our intestines do not absorb phytosterols because there is a certain level at which they become toxic. Despite claims that phytosterol supplements can lower cholesterol, there is data to suggest that they may actually be more harmful to our health than cholesterol itself. This means that supplementing phytosterols may not be beneficial, especially for those who are hyper absorbers. It is important to monitor phytosterol levels in the bloodstream to avoid potentially harmful effects. Ultimately, the focus should be on maintaining a healthy balance of cholesterol rather than relying on phytosterol supplementation.
The Complex Process of Cholesterol Absorption and Transportation: Cholesterol absorption in the body involves multiple components and transporters, and understanding these complexities is crucial in maintaining healthy cholesterol levels.
The absorption and transportation of cholesterol in our bodies is a complex process involving multiple components. Firstly, the intestine absorbs cholesterol because it is an essential ingredient for human life and evolution has ensured that every cell can synthesize cholesterol. However, it is crucial to understand that plasma cholesterol levels do not necessarily reflect cellular cholesterol metrics. The absorption of cholesterol is facilitated by the Neiman pick C1 like protein, which prefers cholesterol over other sterols due to its structure. The enterocytes, the cells in the intestine, then face the decision of whether to transport the cholesterol to the rest of the body or eliminate it. ATP binding cassette transporters play a role in either excreting cholesterol or returning it to circulation through chylomicrons or HDL. Evolution has also provided these transporters with different affinities for phytosterols and stanols, prioritizing the excretion of these compounds. An inability to efficiently excrete sterols due to loss of function mutations in ABC G5 or G8 transporters can result in hyperabsorption of cholesterol. Overall, this conversation highlights the complexities of cholesterol absorption and transportation within the body.
Understanding Cholesterol and its Role in the Body: The body's cholesterol levels are influenced by various factors, with LDL cholesterol being a measure of cholesterol within lipoproteins. The reverse cholesterol transport pathway plays a significant role in eliminating cholesterol from the body.
Cholesterol plays a complex role in the body and is influenced by various factors. LDL cholesterol, which is predominantly found in lipoproteins, is a measure of the cholesterol within these lipoproteins. When these particles invade artery walls, sterols go with them. The intestine has an enzyme called ACAT that esterifies cholesterol into cholesterol ester, a major component of the core of a column icon. However, ACAT does not favor phytosterols, which can retard their entry into the body. HDL particles can also contain phytosterols, indicating a type of dysfunctional HDL particle if measured in high amounts. The process of reverse cholesterol transport involves bringing cholesterol back to the small intestine bypassing the liver, and it can be eliminated through bowel movements. This pathway, known as trans-intestinal cholesterol efflux (TICE), is a significant contributor to cholesterol elimination, varying in individuals from 20% to 60%.
Managing the Review Workflow and Sharing Knowledge in the Field: Thomas Dayspring's expertise in reviewing articles and sharing valuable insights helps him stay updated, while emphasizing the importance of credibility and relevant inquiries.
Thomas Dayspring, an associate editor and reviewer, receives a significant number of articles each year for review. He estimates receiving around 15 articles as an associate editor and double that as a reviewer, totaling approximately 50 papers annually. This workload allows him to stay on top of the literature and gain valuable knowledge in the field. Peter Attia suggests creating a special group to share the most interesting lipid papers with a broader audience. Thomas agrees and suggests reaching out to him through email or following him on Twitter, where he often shares valuable insights and summaries. However, he emphasizes the need for legitimate questions and to prove credibility to avoid unnecessary or irrelevant inquiries. Overall, Thomas Dayspring's extensive exposure to research articles allows him to continually enhance his understanding of cholesterol and related subjects.
The Complex Pathway of Cholesterol Synthesis: Disturbances in cholesterol synthesis can have serious consequences, making it important to understand the multi-stage process and the enzymes involved for maintaining a healthy cholesterol balance.
Cholesterol synthesis is a complex multi-stage process in the body. It starts with a small molecule called acetyl coA and undergoes 20 to 30 individual steps to eventually form cholesterol. The synthetic pathway includes the production of various intermediates, with lenosterol being the first sterol that appears. There are specific enzymes involved in the pathway, such as the desaturase enzyme responsible for saturating the double bond at carbon 24 in desmosterol to convert it into cholesterol. Disturbances in this pathway can lead to conditions like Dysmosteroidosis, a genetic deficiency in the delta 24 desaturase enzyme, which can have severe consequences, especially if it occurs during pregnancy. Understanding these processes and enzymes is crucial for maintaining proper cholesterol balance in the body.
Understanding Cholesterol Metabolism and its Complexity: Cholesterol metabolism varies in different tissues, with the brain producing its own cholesterol and the body primarily excreting it rather than using it for energy.
Cholesterol metabolism in the body is a complex process that involves various pathways and enzymes. One important pathway is the Can Dutch Russell pathway, which plays a role in the production of cholesterol. It's worth noting that cholesterol metabolism may be tissue-specific, meaning that different tissues in the body have different mechanisms for cholesterol synthesis and utilization. Additionally, cholesterol in the brain functions independently from cholesterol in the rest of the body, as the brain produces its own cholesterol and does not rely on LDL particles for delivery. Furthermore, cholesterol can only be converted into specific substances in certain tissues, and the body primarily excretes cholesterol rather than using it for energy.
Cholesterol and its role in metabolism: Cholesterol is not metabolized like other fats and cannot be used for energy. Our bodies have evolved different pathways, like ketosis, to break down fats and preserve muscle mass. Cellular cholesterol levels are regulated for optimal function.
Cholesterol cannot be metabolized and produce ATP like other fats. While carbon-carbon and carbon-hydrogen bonds do release energy during metabolism, the enzymatic machinery in our bodies cannot break down the bonds in cholesterol to liberate its chemical energy. This is likely a deliberate design in evolution, as metabolizing cholesterol during periods of fasting could be harmful and deplete important cell membranes and hormones. Instead, our bodies have evolved the pathway of ketosis to metabolize fats for energy, preserving muscle mass and avoiding catabolic destruction. It is also important to note that cholesterol levels in the plasma do not accurately reflect cellular cholesterol, and the synthesis, influx, and efflux of cholesterol are tightly regulated to maintain cellular function.
Understanding Cholesterol Homeostasis and its Importance in Lipidology: Cholesterol homeostasis involves the regulation of cholesterol synthesis, uptake, and circulation in the body, and understanding its movement over time is crucial in lipidology. HDL particles play a vital role in supplying cholesterol to tissues and may rely on other tissues for replenishment.
Cholesterol homeostasis is a complex process that involves the regulation of cholesterol synthesis, uptake, and circulation in the body. While some tissues, such as the adrenal gland, can produce their own cholesterol, others rely on exogenous cholesterol sources like LDL particles. HDL particles act as a circulating reservoir of cholesterol, providing it to tissues that require it. The measurement of plasma lipids only provides information on the current state of cholesterol in the bloodstream and does not reflect what is happening within cells or endothelium. Understanding cholesterol flux and its movement over time is crucial in lipidology. In times of crisis or ongoing demand, HDLs may deplete their cholesterol stores and rely on other tissues, such as adipocytes, to replenish them.
