Blood lipids: Why are LDL levels normal, but I'm still at risk of heart disease?
Many people feel relieved when they have a yearly health checkup and the results show that their blood lipid levels are within the normal range. However, in reality, a significant number of heart disease patients have LDL levels that are considered "normal."
The crucial question is: Are we looking at "incomplete information"?
From the perspective of preventive medicine, assessing the risk of heart disease may need to go beyond simply looking at basic cholesterol figures.
What are blood fats and why does the body need them?
Cholesterol in the blood is not "something to be eliminated," but rather an important substance that the body uses in many systems, such as:
It is a component of the cell membrane.
It is a precursor to hormones such as estrogen, testosterone, and cortisol.
Used to produce vitamin D.
It is related to the nervous system and the brain.
The body produces approximately [amount] cholesterol on its own. 70–80% (average 75%) It is processed in the liver, a key mechanism for maintaining the body's balance (NIH, AHA).
LDL is not the only answer.
Generally, blood lipid tests will report values...
Total Cholesterol
LDL-C
HDL-C
Triglycerides
But what many people may not know is... The LDL level commonly tested refers to the "amount of cholesterol per particle," not the "number or quality of particles." Which means that Two people with the same LDL level may have "different" risks of heart disease. Because the particle number and particle quality are factors that affect risk differently.
This may lead to inaccurate risk assessments in some cases. In-depth lipid profile such as Advanced Lipid Profile This may help to understand the details of fat particles better.
Large LDL (Large LDL): It tends to be "less atherogenic" compared to small dense LDL, but this does not mean it is "without risk," especially if a high particle count is also present.
Small Dense LDL It can easily enter the bloodstream and is associated with plaque formation.
Small dense LDL is often associated with metabolic syndrome, a major risk factor for non-communicable diseases (NCDs). It is frequently linked to conditions such as:
Insulin resistance
High blood sugar levels
High triglyceride levels
This reflects a metabolic dysfunction in the body.
Oxidized LDL: An inflammatory trigger.
LDL poses a risk not only due to its "quantity," but the risk increases when LDL undergoes a chemical change called... oxidationThis process involves: Oxidative stress This is caused by an imbalance between free radicals and antioxidants in the body.
Oxidized LDL It plays a vital role in...
It stimulates inflammation in the blood vessel walls.
Promotes the accumulation of fat and the formation of atherosclerotic plaque.
This process usually involves various factors such as:
chronic stress
Consumption of processed foods.
High blood sugar
Oxidized LDL also plays a role in stimulation. macrophages (a type of white blood cell) And that leads to the occurrence of... foam cells (fat cells in the blood vessel walls) This is an important step in the birth process. atherosclerosis (hardening and narrowing of the arteries)
ApoB: Represents the "number of risky particles".
ApoB is a protein found on pathogenic lipid particles. 1 particle = 1 ApoB Therefore, it reflects the "number of particles that may pose a risk" more accurately than LDL-C, which means that...
Some people may find that...
LDL levels are normal.
But ApoB is high.
This may indicate additional hidden risks, as seen in modern medical practice, such as: ESC/EAS guidelines ApoB has been given importance in assessing cardiovascular risk, especially in individuals with metabolic abnormalities (metabolic risk).
Lp(a): Genetic risk
Lp(a) is a type of fat that is determined by genetics.
It can be found approximately 20–30% of the global population And among Asian populations, including Thais, it is commonly found in the range of approximately... 20%
The root cause of heart disease may not just be fat.
Current research indicates that heart disease is involved in multiple mechanisms, such as:
Chronic inflammation
This concept is consistent with large-scale research such as: INTERHEART study Metabolic and inflammatory factors have been found to play a significant role in global heart disease risk.
Indicators such as hs-CRP (high-sensitivity C-reactive protein) Elevated levels may reflect chronic low-grade inflammation in the body, which has been linked to an increased risk of cardiovascular disease in several studies.
However, hs-CRP is only one indicator and should be used in conjunction with metabolic data and other risk factors for a comprehensive assessment.
Insulin resistance
It is one of the key mechanisms that affect the risk of heart disease, and is related to...
Elevated triglyceride levels.
The increase of Small dense LDL
Fat accumulation in the liver (fatty liver)
Endothelial Dysfunction
It plays a crucial role in the early stages of cardiovascular disease. When the endothelial lining of blood vessels malfunctions, it can lead to inflammation, the adhesion of inflammatory cells, and the accumulation of fat in the blood vessel walls.
Who should consider getting a comprehensive lipid profile test?
You may be in a group that should undergo further testing if you have the following characteristics:
My cholesterol levels are normal, but I'm still experiencing fatigue.
Losing weight is difficult, especially belly fat.
I have a family history of heart disease.
Having high blood sugar levels, or prediabetes.
High triglycerides or low HDL.
I'm stressed and not getting enough sleep.
How do in-depth examinations help us understand our bodies better?
In some cases, your doctor may consider additional tests, such as:
Advanced Lipid Profile: Analyze the level and characteristics of fat particles.
ApoB and Lp(a): Assess particle count and genetic risk.
hs-CRP : Assess the level of inflammation in the body.
Insulin / HOMA-IR : Assess insulin resistance.
These tests are not aimed solely at "finding abnormalities," but rather at providing a deeper understanding of the body and designing personalized care.
In the field of preventive medicine, a comprehensive preventive assessment (CPA) that covers all aspects of health is essential.
Because modern healthcare may no longer be about waiting for "abnormal results" to appear. But it's about understanding the body before problems arise.
Important questions you might need to ask yourself.
Does your test result "reflect the actual risk" or only partially?
Do you know your own ApoB or Lp(a)?
Is your lifestyle contributing to inflammation in your body?
Q: Even with normal LDL levels, are I still at risk of heart disease? A: Yes, in some cases, normal LDL-C levels may not reflect the number or quality of fat particles, such as ApoB or small dense LDL, which affects the risk of heart disease.
Q: What is the difference between ApoB and LDL? A: LDL-C measures the "amount of cholesterol" in particles, while ApoB reflects the "number of risk-prone fat particles," which in some cases may provide more accurate risk information.
Q: What is Lp(a) and is it necessary to get tested? A: Lp(a) is a genetically determined lipid profile found in approximately 20–30% populations and increases the risk of heart disease. It is generally recommended to have it checked at least once in a lifetime, especially for those with a family history.
Q: Is a regular lipid test sufficient? A: Basic testing is sufficient for general screening, but for individuals with additional risk factors, more in-depth testing may be considered for a more detailed risk assessment.
Q: Who should consider getting a comprehensive lipid profile test? A: Individuals with risk factors such as a family history of heart disease, high triglycerides or low HDL, insulin resistance, or prediabetes.
Summary of key points
LDL-C alone may not reflect all the risks.
ApoB and Lp(a) help to more accurately assess the number and risk of fat particles.
Small dense LDL and oxidized LDL play a role in the development of atherosclerosis.
Inflammation and insulin resistance are key mechanisms in heart disease.
This information is provided for general medical knowledge and cannot replace a diagnosis or advice from a doctor. If you experience any unusual symptoms, you should consult a doctor before making any health-related decisions.
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