Ketogenic Diets and Heart Health: New Research Challenges Conventional Wisdom
Discover the surprising truth about ketogenic diets and LDL cholesterol. New research challenges conventional wisdom on heart health risk
DR T S DIDWAL MD
10/9/20249 min read
According to a study published in the JACC Advances, the ketogenic diet presents a challenge to conventional wisdom regarding LDL cholesterol and heart disease risk. Researchers found that lean mass hyper-responders (LMHRs), characterized by very high LDL cholesterol levels, did not exhibit increased plaque buildup or heart disease risk despite these elevated levels. This suggests that the context of metabolic health and diet-induced high cholesterol may influence cardiovascular risk differently than genetically-caused high cholesterol. While this study provides intriguing insights, further research is needed to confirm these findings and understand the long-term implications for heart health.
Key Points
LMHRs: Lean mass hyper-responders are individuals who experience a significant increase in LDL cholesterol when adopting a ketogenic diet.
High LDL, Low Risk: Despite very high LDL levels, LMHRs did not show increased coronary artery calcium or plaque buildup.
Metabolic Health Matters: This study emphasizes the importance of overall metabolic health beyond single markers like LDL cholesterol.
Diet-Induced vs. Genetic High Cholesterol: The findings suggest that diet-induced high cholesterol may have different implications than genetically-caused high cholesterol.
Individual Variability: Responses to diet can vary widely, and what works for one person may not be suitable for another.
Need for Further Research: Larger studies and randomized controlled trials are needed to confirm these findings and understand the long-term implications.
Personalized Approach: The study highlights the importance of personalized medicine, considering individual responses to diet and tailoring approaches accordingly.
Ketogenic Diet, LDL Cholesterol, and Heart Disease: A New Perspective
The rise in popularity of low-carbohydrate and ketogenic diets has brought with it a new phenomenon that's catching the attention of researchers and health professionals alike: the lean mass hyper-responder (LMHR). This unique metabolic profile, characterized by dramatically elevated LDL cholesterol levels in otherwise healthy individuals following a ketogenic diet, has raised important questions about our understanding of cholesterol, diet, and heart disease risk.
A groundbreaking new study, recently published in the Journal of the American College of Cardiology, sheds light on this intriguing topic. Let's dive into the key findings and what they might mean for those following a ketogenic diet or considering one.
Understanding Lean Mass Hyper-Responders (LMHRs)
Before we get into the study details, it's important to understand what exactly a lean mass hyper-responder is. LMHRs are typically lean, metabolically healthy individuals who experience a significant increase in LDL cholesterol (often to levels above 200 mg/dL) when adopting a very low-carbohydrate or ketogenic diet. This occurs alongside elevated HDL cholesterol (the "good" cholesterol) and low triglycerides.
The LMHR profile is defined as:
LDL cholesterol ≥200 mg/dL
HDL cholesterol ≥80 mg/dL
Triglycerides ≤70 mg/dL
This combination is puzzling because while high LDL is traditionally considered a risk factor for heart disease, high HDL and low triglycerides are typically associated with better cardiovascular health.
The Study: Ketogenic Diet-Induced Elevations in LDL Cholesterol
Researchers set out to investigate whether these diet-induced elevations in LDL cholesterol were associated with an increased risk of coronary artery disease. They compared 80 individuals following a ketogenic diet who had developed very high LDL levels (≥190 mg/dL) to 80 matched controls from a population-based study (the Miami Heart Study).
Key details of the ketogenic diet (KETO) group:
Average LDL cholesterol: 272 mg/dL
Average HDL cholesterol: 90 mg/dL
Average triglycerides: 64 mg/dL
Average time on the ketogenic diet: 4.7 years
Average BMI: 22.5 kg/m² (normal weight)
The control group had more typical cholesterol levels, with an average LDL of 123 mg/dL.
Measuring Heart Disease Risk
To assess heart disease risk, the researchers used two advanced imaging techniques:
Coronary Artery Calcium (CAC) Score: This test detects and quantifies calcium buildup in the coronary arteries, which is a marker of atherosclerosis (hardening and narrowing of the arteries).
Coronary Computed Tomography Angiography (CCTA): This detailed imaging test allows for the visualization and assessment of plaque buildup in the coronary arteries.
Surprising Results
Given the extremely high LDL levels in the KETO group, many would expect to see significantly more plaque buildup and calcium in their coronary arteries. However, the results were surprising:
No difference in coronary artery calcium scores: The median CAC score was 0 for both groups, indicating no detectable calcium buildup in the majority of participants from both the KETO and control groups.
Similar plaque burden: The CCTA results showed no significant difference in overall plaque burden between the two groups. The median total plaque score was 0 for the KETO group and 1 for the control group, a difference that was not statistically significant.
No correlation between LDL levels and plaque: Perhaps most surprisingly, there was no correlation found between LDL cholesterol levels and the amount of plaque in the coronary arteries, even with LDL levels as high as 591 mg/dL in some participants.
These findings challenge the conventional wisdom that high LDL cholesterol levels invariably lead to increased plaque buildup and heart disease risk.
Implications and Interpretations
While this study doesn't provide all the answers, it raises several important points for consideration:
Context matters: The results suggest that extremely high LDL cholesterol in the context of a ketogenic diet, especially when accompanied by high HDL and low triglycerides, may not carry the same risk as high LDL in other contexts.
Metabolic health is multifaceted: The study highlights the importance of looking beyond single markers like LDL cholesterol and considering overall metabolic health. The KETO group, despite very high LDL levels, showed no signs of increased cardiovascular risk based on the imaging results.
Diet-induced vs. genetic high cholesterol may differ: The study specifically excluded individuals with familial hypercholesterolemia (a genetic condition causing high cholesterol). This suggests that diet-induced elevations in LDL may have different implications than those caused by genetic factors.
The role of inflammation: Some researchers hypothesize that the anti-inflammatory effects of a ketogenic diet might offset potential risks associated with high LDL cholesterol. While this study didn't directly measure inflammation, it's an area worthy of further investigation.
Particle size and type may matter: The study didn't report on LDL particle sizes or types. Some evidence suggests that large, buoyant LDL particles (which may be more common on a ketogenic diet) might be less atherogenic than small, dense LDL particles.
Individual variability: It's crucial to remember that this study looks at averages across groups. Individual responses to diet can vary widely, and what works for one person may not be suitable for another.
Limitations and Future Research
While these findings are intriguing, it's important to acknowledge the study's limitations:
Sample size: With 80 participants in each group, this is a relatively small study. Larger studies will be needed to confirm these findings.
Duration: While an average of 4.7 years on a ketogenic diet is significant, it may not be long enough to fully assess long-term cardiovascular risk.
Observational nature: This study shows association, not causation. Randomized controlled trials would be needed to definitively prove that ketogenic diets don't increase heart disease risk despite raising LDL cholesterol.
Matched controls: While the control group was matched on several factors, they had a slightly higher average BMI and different lipid profiles. A perfectly matched control group would strengthen the findings.
The researchers acknowledge these limitations and emphasize the need for further study. They are currently conducting a prospective study to track changes in coronary plaque over time in LMHR individuals, which should provide more definitive answers.
Practical Implications: What Does This Mean for You?
If you're following a ketogenic diet or considering one, here are some key takeaways:
Individual response varies: Not everyone on a ketogenic diet will develop the LMHR profile. Many people see improvements in all their lipid markers on a ketogenic diet.
Regular monitoring is crucial: If you're on a ketogenic diet, regular lipid panel testing is important to understand how your body is responding.
Consider advanced testing: If you do develop very high LDL cholesterol on a ketogenic diet, discussing advanced testing options (like CAC scoring or CCTA) with your healthcare provider might provide more insight into your actual heart disease risk.
Look at the whole picture: Don't fixate solely on LDL cholesterol. Consider other markers of metabolic health, including HDL cholesterol, triglycerides, blood pressure, and measures of insulin sensitivity.
Personalize your approach: If you're concerned about elevated LDL cholesterol on a ketogenic diet, there are strategies to potentially lower it while maintaining ketosis, such as adjusting the types of fats consumed or incorporating intermittent carbohydrate refeeds.
Work with knowledgeable healthcare providers: If you're an LMHR, it's crucial to work with healthcare providers who are familiar with this phenomenon and up-to-date on the latest research.
Potential Downsides of the Ketogenic Diet
While the ketogenic diet has shown promise for weight loss and managing certain health conditions, it's not without potential drawbacks. The diet's restrictive nature can make it challenging to maintain long-term and may lead to nutrient deficiencies, particularly in fiber, vitamins, and minerals found in fruits, whole grains, and certain vegetables. Some people experience short-term side effects known as the "keto flu," including fatigue, headaches, and irritability. The high fat content, especially if focused on saturated fats, might raise concerns for heart health in some individuals. Additionally, the diet may not be suitable for everyone, particularly those with certain medical conditions or taking specific medications. Long-term effects of the diet are still being studied, and there are concerns about its impact on gut health, bone density, and kidney function in some populations.
Conclusion: Challenging Conventional Wisdom
This study represents a significant challenge to the conventional wisdom about LDL cholesterol and heart disease risk. It suggests that in the context of a ketogenic diet and overall metabolic health, very high LDL cholesterol may not necessarily translate to increased plaque buildup or heart disease risk.
However, it's crucial to interpret these findings cautiously. This is a single study with limitations, and it doesn't negate the large body of evidence linking elevated LDL cholesterol to increased cardiovascular risk in other contexts.
What this study does is open up important new avenues for research. It highlights the complexity of human metabolism and the need for more nuanced approaches to assessing cardiovascular risk. It also underscores the importance of personalized medicine – recognizing that dietary effects can vary widely between individuals. The present study is recent and more research is needed to confirm the long-term implications of the ketogenic diet on heart health in LMHRs.
As we await further research, including the results of the ongoing prospective study, this work provides a fascinating glimpse into the complex interplay between diet, cholesterol, and heart health. It reminds us that in nutrition and health, absolutes are rare, and context is key.
For those following or considering a ketogenic diet, especially those who might fall into the LMHR category, this study offers reassurance but not definitive answers. As always, major dietary changes should be undertaken with careful consideration and, ideally, under the guidance of knowledgeable healthcare providers.
The field of nutrition science is constantly evolving, and studies like this one push us to question our assumptions and deepen our understanding. While we may not have all the answers yet, asking these questions is the first step toward more personalized and effective approaches to diet and health.
FAQs
1. What are LMHRs? Lean mass hyper-responders are individuals who experience a significant increase in LDL cholesterol when adopting a ketogenic diet. They are typically lean and metabolically healthy.
2. Why do LMHRs have elevated LDL cholesterol on a ketogenic diet? The exact reasons for this phenomenon are not fully understood, but it may be related to factors such as changes in bile acid metabolism, increased production of LDL particles, or altered receptor activity.
3. Does high LDL cholesterol in LMHRs increase heart disease risk? The study discussed in the blog post suggests that high LDL cholesterol in LMHRs may not necessarily translate to increased plaque buildup or heart disease risk, especially when accompanied by high HDL and low triglycerides. However, more research is needed to confirm this.
4. Should individuals on a ketogenic diet be concerned about LMHR status? Regular lipid panel testing is recommended for those on a ketogenic diet to monitor cholesterol levels. If you develop very high LDL cholesterol, it's important to consult with your healthcare provider to discuss your specific risk factors and potential management strategies.
5. Are there ways to lower LDL cholesterol while maintaining a ketogenic diet? Some potential strategies include adjusting the types of fats consumed, incorporating intermittent carbohydrate refeeds, or exploring additional dietary modifications under the guidance of a healthcare professional.
6. Can anyone become an LMHR? Individual responses to diet can vary widely, and not everyone on a ketogenic diet will develop the LMHR profile. Factors such as genetics, metabolic rate, and overall health may influence susceptibility.
7. Is it safe to continue a ketogenic diet if you're an LMHR? The decision to continue a ketogenic diet should be made in consultation with your healthcare provider, considering your individual risk factors and the potential benefits and risks.
8. What are the potential benefits of a ketogenic diet? Potential benefits of a ketogenic diet include weight loss, improved blood sugar control, and reduced seizures in individuals with epilepsy. However, these benefits may vary from person to person.
Glossary of Terms:
LDL-C: Low-Density Lipoprotein Cholesterol, often referred to as "bad" cholesterol.
HDL-C: High-Density Lipoprotein Cholesterol, often referred to as "good" cholesterol.
Triglycerides: A type of fat found in the blood.
LMHR: Lean Mass Hyper-Responder, individuals who exhibit very high LDL-C, high HDL-C, and low triglycerides on a low-carb diet.
Ketogenic Diet (KETO): A very low-carbohydrate, high-fat diet that induces a state of ketosis.
BMI: Body Mass Index, a measure of body fat based on height and weight.
CAC: Coronary Artery Calcium, a measure of calcified plaque in coronary arteries.
CCTA: Coronary Computed Tomography Angiography, an imaging technique to visualize coronary arteries.
Atherosclerosis: The buildup of plaque in arteries.
ASCVD: Atherosclerotic Cardiovascular Disease.
ApoB: Apolipoprotein B, a protein component of many lipoproteins, including LDL.
VLDL: Very Low-Density Lipoprotein, a type of lipoprotein produced by the liver.
Familial Hypercholesterolemia: A genetic disorder characterized by very high cholesterol levels.
Atherogenic: Promoting the formation of fatty plaques in the arteries.
Metabolic Syndrome: A cluster of conditions that increase the risk of heart disease, stroke, and diabetes.
Related Articles
Diet and Heart Disease: A Guide to Lower Cholesterol and Protect Your Heart
Journal Reference
Budoff, M, Manubolu, V, Kinninger, A. et al. Carbohydrate Restriction-Induced Elevations in LDL-Cholesterol and Atherosclerosis: The KETO Trial. JACC Adv. 2024 Aug, 3 (8) .https://doi.org/10.1016/j.jacadv.2024.101109
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