EP147: Talking LDL Particle Size

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I’m a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients. Podcast Summary Introduction Dr. Warrick Bishop, a practicing cardiologist and patient education advocate, hosts this episode with Dr. Karam Kostner, a leading lipidologist and colleague. The episode explores LDL particle size—a topic that frequently appears in social media and diet-related discussions—and examines whether different sizes of LDL cholesterol particles pose varying risks to heart health. Key Takeaways: Lipoproteins are protein carriers that transport cholesterol through the bloodstream; they can be understood as "buses" or "sedans" carrying cholesterol molecules, with density and size varying based on how packed they are. While LDL particles do come in different sizes and densities, approximately 99% of all LDL is problematic regardless of particle size, as clinical trials consistently show that all LDL ends up in arteries and contributes to plaque buildup. Small, dense LDL particles may be slightly more atherogenic (artery-damaging) than larger particles due to their ability to penetrate vessel walls more easily, but this distinction has limited clinical importance. For clinical practice, measuring LDL particle size is not recommended because reducing overall LDL cholesterol—regardless of particle composition—effectively reduces cardiovascular risk in both diabetic and non-diabetic patients. Diet, exercise, diabetes, and medical therapies (statins, fibrates, ezetrol) all influence LDL particle size, but the primary clinical focus should remain on lowering total LDL rather than targeting specific particle sizes. Particle size testing, while commercially available and scientifically interesting, is primarily a research tool with limited practical utility for patient management at this stage. The danger exists that patients with favorable particle size profiles may incorrectly assume they don't need aggressive LDL-lowering therapy, similar to false reassurance from high HDL levels. Clinical imaging (such as cardiac CT to visualize coronary calcium and plaque burden) and measurement of Lipoprotein(a) are more clinically useful tools than particle size analysis for assessing cardiovascular risk.