Peter Attia MD - The limitations of using HDL cholesterol as a marker for heart health | Tom Dayspring
The discussion highlights the misconception that high HDL cholesterol, often termed 'good cholesterol,' guarantees cardiovascular protection. HDL particles perform various functions, some of which are cardioprotective, while others can be harmful. The functionality of HDL is not determined by its cholesterol content but by its protein and phospholipid composition. Over 150 proteins and numerous phospholipids influence HDL's role in the body, making it difficult to assess HDL functionality through standard blood tests.
The conversation also points out that individuals with high HDL cholesterol can still develop cardiovascular diseases, such as atherosclerosis, and other conditions like cancer or dementia. This is because HDL functionality, not cholesterol levels, determines its protective or harmful effects. The example of a patient with high HDL and low LDL cholesterol who developed atherosclerosis underscores the need for comprehensive cardiovascular risk assessment beyond HDL cholesterol levels. The recommendation is to focus on lowering ApoB levels and using other diagnostic tools, like calcium scoring, to evaluate cardiovascular risk.
Key Points:
- HDL cholesterol levels do not correlate with HDL functionality or cardiovascular protection.
- HDL functionality is determined by its protein and phospholipid content, not cholesterol levels.
- High HDL cholesterol can still be associated with cardiovascular diseases and other health issues.
- ApoB levels should be monitored and managed to assess cardiovascular risk effectively.
- Calcium scoring and other diagnostic tools are recommended for comprehensive risk assessment.
Details:
1. 🎙️ Debunking HDL Myths
- HDL cholesterol is often referred to as 'good' cholesterol, but recent studies suggest that high HDL levels are not always beneficial. For example, extremely high HDL levels (above 90 mg/dL) were associated with increased cardiovascular risk in some studies.
- The traditional view that higher HDL is always better is being challenged. Research indicates that HDL functionality, not just quantity, is more important for cardiovascular health.
- Genetic studies have shown that simply raising HDL levels pharmacologically does not necessarily reduce the risk of heart disease.
- A comprehensive approach to heart health should focus on overall lipid profile, including LDL and triglycerides, rather than solely on HDL levels.
2. 🧠 The Protective Nature of HDL
- HDL is known for its protective role in cardiovascular health, acting as a 'scavenger' that removes excess cholesterol from the bloodstream and transports it to the liver for excretion.
- Previous podcasts have covered the detailed mechanisms by which HDL functions, such as reverse cholesterol transport and anti-inflammatory properties.
- HDL's protective nature is supported by studies showing that higher levels of HDL cholesterol are associated with a lower risk of heart disease and stroke.
- Research has demonstrated that each 1 mg/dL increase in HDL cholesterol is linked to a 2-3% decrease in cardiovascular risk.
- Emerging therapies aim to enhance HDL function rather than just increase HDL levels, focusing on improving its efficiency in cholesterol removal and anti-inflammatory actions.
3. 🔍 Misconceptions in Cholesterol Information
- The misconception that high HDL (good cholesterol) levels alone ensure cardiovascular health is widespread and incorrect.
- HDL's protective role depends on its functionality, not merely its concentration in the blood.
- Current blood tests fail to assess HDL functionality, which is crucial for understanding its protective benefits.
- Public misinformation persists due to oversimplified media messages emphasizing HDL levels over functionality.
- HDL functionality involves its ability to transport cholesterol from arteries to the liver, a process not measured by standard tests.
- Media often simplifies HDL as 'good cholesterol,' neglecting the complex role of its functionality in preventing heart disease.
4. 💡 HDL's Complex Role in Cardiovascular Health
- HDL particles are critical to cardiovascular health, performing vital functions such as cholesterol transport and anti-inflammatory actions, which are essential to the cardiovascular system and potentially benefit other tissues.
- Educating patients on HDL's functions is crucial, as outdated beliefs may lead them to overlook its significance, focusing only on LDL.
- The evolving understanding of lipoproteins emphasizes the need for healthcare providers to update their knowledge and avoid perpetuating misconceptions about cholesterol, particularly the oversimplified view of HDL as 'good' cholesterol.
5. 📊 Decoding HDL Functionality and Levels
- HDL functionality is independent of HDL cholesterol levels; the cholesterol level in the blood does not correlate with HDL's protective or harmful functions.
- Individuals with low HDL cholesterol levels are often considered at high cardiovascular risk, but this is not always accurate for everyone.
- Some people with high HDL cholesterol levels may still develop diseases like atherosclerosis, breast cancer, or dementia, demonstrating that high levels are not universally protective.
- Assessing HDL functionality rather than just HDL cholesterol levels is critical for understanding cardiovascular and other health risks.
- Studies show that HDL functionality is a better predictor of cardiovascular health than HDL cholesterol levels alone.
- For instance, research indicates that measuring HDL's anti-inflammatory properties provides better insights into cardiovascular risk than traditional cholesterol tests.
6. 🔬 HDL's Intricate Properties
6.1. HDL's Protein Content: Impact and Functions
6.2. Phospholipid Influence on HDL Functionality
7. 🧪 Understanding HDL Measurements
- Measuring HDL phospholipid content is complex due to the presence of hundreds of phospholipids, making it difficult to pronounce or recognize many of them.
- Of the 150 proteins associated with HDL, the average doctor might only be familiar with about 10, indicating a gap in knowledge regarding HDL's proteome.
- Determining a patient's HDL functionality is challenging, as adverse effects with high HDL cholesterol are linked to dysfunctional HDL, potentially due to its proteome or phospholipid content.
- Dysfunctional HDL can result from specific proteome or phospholipid imbalances, affecting its role in cholesterol transport and cardiovascular health.
8. 🔄 Rethinking HDL and APOB Relationships
- High APOB is consistently found in individuals with low HDL cholesterol who develop atherosclerosis, indicating APOB as a critical risk factor.
- In past observational trials like Framingham, the absence of APOB measurement led to an incomplete understanding of cholesterol's impact on cardiovascular disease.
- High triglycerides, even at levels of 130, can result in low HDL cholesterol, leading to underestimated risk if APOB is not evaluated.
- Effective treatment for those with low HDL and cardiovascular risk should focus on lowering APOB and non-HDL cholesterol levels.
- It is essential to measure APOB in all individuals, regardless of HDL levels, as it is a more accurate indicator of cardiovascular risk.
9. 📈 Case Studies on HDL Complexity
- A person with consistently high HDL cholesterol (>100 mg/dL) and low LDL cholesterol (<100 mg/dL) was considered in excellent health, yet this profile can sometimes mask underlying cardiovascular risk.
- Despite favorable cholesterol numbers, a calcium score test was recommended, revealing high levels of arterial calcification, which is a significant risk factor for atherosclerosis.
- As a result of the high calcium score, aggressive treatment was initiated, including double therapy, to reduce cardiovascular risk, aiming to maintain an apob level in the 20 to 30 range.
- This case highlights that high HDL, traditionally seen as protective, can be a marker of dysfunctional HDL, which might not effectively protect against cardiovascular disease.
- The findings suggest the importance of comprehensive risk assessments beyond standard lipid profiles, including calcium score testing, to identify hidden cardiovascular risk.
10. 🎵 Final Thoughts
- No actionable insights or data points are present in this music-only segment.