#515: Does Dietary Fat Quality Causally Affect Atherosclerosis Risk? – Jacob Christensen, PhD
Mar 12, 2024
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Exploring whether dietary fat quality affects atherosclerosis risk, experts discuss impact of fats on cholesterol levels and cardiovascular health. Focus shifts to unsaturated fats' potential benefits over saturated fats. Genetic factors and individual responses also play a role in fat's impact on atherosclerosis risk.
Impact of Dietary Fat on Atherosclerotic Cardiovascular Disease
The podcast delves into the crucial relationship between dietary fat quality and its impact on atherosclerotic cardiovascular disease (ASCVD) risk. Dr. Jakob Christensen, a researcher focused on cardiovascular diseases and lipid metabolism, highlights the importance of LDL particle concentration in ASCVD risk and the causal relationship between dietary fat quality and LDL particles. By exploring multiple lines of evidence from genetic studies, randomized controlled trials, and epidemiological data, the podcast emphasizes the significant role of dietary fat composition in affecting ASCVD risk.
Genetic Evidence and Effects on Plasma LDL Particles
The discussion focuses on the genetic evidence supporting the causal link between LDL particle concentration and atherosclerotic cardiovascular disease (ASVD) risk. Through GWAS data, Mendelian randomization studies, and investigations into familial hypercholesterolemia (FH), the podcast presents compelling findings showing the impact of genetic variations on LDL levels and its association with ASVD risk. Clinical trials on statins further corroborate these genetic insights, demonstrating the relationship between LDL particle reduction and decreased ASVD risk.
Mechanisms of Fat Quality on LDL Particles
Exploring the mechanistic pathways, the podcast highlights how dietary fat quality influences LDL particle concentration by regulating the expression of LDL receptors in the liver. The shift from saturated fats to unsaturated fats, particularly polyunsaturated fats, enhances the hepatic removal of LDL particles from circulation, promoting reverse cholesterol transport. Detailed mechanisms proposed by researchers, like John Deitchy, shed light on how fatty acids affect cholesterol ester synthesis, LDL receptor activity, and ultimately plasma cholesterol levels, providing insights into the physiological processes involved.
Human Response Variation to Dietary Fats
Human responses to dietary fats exhibit considerable variation, creating challenges in drawing definitive conclusions. Studies, including n=1 trials, demonstrate both random and non-random variations in response, making it crucial to consider the temporal consistency and test exposures multiple times. The average response to dietary fats can be predicted accurately at a group level, although individual variations exist, suggesting a bell-shaped distribution of responses.
Impact of Dietary Fat Quality on Health
Controlled trials in animals and humans serve as pivotal evidence to assess the impact of dietary fat quality on lipid levels. Saturated and trans fats, as well as dietary cholesterol, increase LDL cholesterol levels; in contrast, certain polyunsaturated fats lower LDL cholesterol. The saturation levels of fatty acids, such as stearic acid and palmitic acid, influence LDL cholesterol responses, highlighting the intricate relationship between dietary fats and lipid profiles.
The question of whether dietary fat quality causally affects atherosclerosis risk has been a subject of extensive research and debate within the field of nutrition and cardiovascular health.
Atherosclerosis, the build-up of plaque in arteries, is a key factor in the development of cardiovascular diseases, including heart attacks and strokes. Traditionally, dietary fat has been implicated in contributing to atherosclerosis, with a focus on reducing overall fat intake. However, recent studies have shifted the focus towards the quality of dietary fats rather than their quantity.
Not all fats are created equal, and researchers are now paying closer attention to the types of fats consumed in the diet. Saturated fats, commonly found in animal products and some tropical oils, have long been associated with increased cholesterol levels and atherosclerosis. On the other hand, unsaturated fats, including monounsaturated and polyunsaturated fats found in olive oil, nuts, and fish, have been linked to potential cardiovascular benefits. Research suggests that replacing saturated fats with unsaturated fats may have a positive impact on blood lipid profiles and reduce the risk of atherosclerosis.
Additionally, genetic factors and individual responses to different fats may play a role in how dietary fats impact atherosclerosis risk.
In this episode, Dr. Jacob Christensen discusses the research in this area and some conclusions about whether we can say dietary fat quality causally increases atherosclerotic cardiovascular disease (ASCVD) risk. This includes looking at the relationship between low-density lipoprotein (LDL) particles and ASCVD, the link between dietary fat quality and LDL particles, and then finally the relationship between dietary fat quality, LDL particles, and ASCVD.
About the Guest:
Jacob J. Christensen is a clinical dietitian and researcher at University of Oslo. His research interests include cardiovascular diseases, lipid metabolism, nutrition, genomics and data science.
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