Good vs Bad Cholesterol: Why HDL and LDL Matter
by: Dr. Paul Chang, General Practitioner, Regis Medical
Last updated: December 7, 2025
Most people have heard of “good” and “bad” cholesterol, but what do these terms actually mean, and why do they matter for long-term health? In Singapore, cholesterol issues are extremely common. According to the Ministry of Health, 1 in 3 adults has high cholesterol, and many don’t even know it because the condition has no obvious symptoms in the early stages.
Understanding how cholesterol works, especially HDL and LDL, helps you take control of your heart health, prevent complications, and make informed decisions about screening and lifestyle changes.
Manage High Cholesterol with Regis Medical
Patient-first, Holistic, Dedicated Healthcare
What Exactly Is Cholesterol?
Cholesterol is a waxy, fat-like substance found in your blood. Your body needs it to build cells, produce hormones, and make vitamin D.
But cholesterol becomes a problem when levels rise too high, especially when “bad” cholesterol builds up in your arteries, increasing the risk of:
- Heart disease
- Stroke
- Peripheral artery disease
- High blood pressure
- Kidney damage
Because cholesterol circulates in the bloodstream, the type and level of cholesterol determine whether it protects your heart, or harms it.
Good vs Bad Cholesterol: What’s the Difference?
1. HDL - The “Good” Cholesterol
HDL (High-Density Lipoprotein) is protective for your heart.
It acts like a “clean-up crew” that removes excess cholesterol from your bloodstream and transports it to the liver for disposal.
Why HDL Is Considered Good
- It prevents cholesterol buildup in your arteries.
- Higher HDL levels are linked to lower risk of heart attack and stroke.
- It reduces inflammation and oxidative stress in blood vessels.
Ideal HDL Levels
- Men: Above 1.0 mmol/L
- Women: Above 1.3 mmol/L
Higher levels are better.
Common Reasons for Low HDL
- Smoking
- Sedentary lifestyle
- Obesity
- Diet high in refined carbs
- Poorly controlled diabetes
- Genetics
2. LDL - The “Bad” Cholesterol
LDL (Low-Density Lipoprotein) carries cholesterol to your tissues. When too much accumulates, it sticks to artery walls, forming fatty plaques.
Why LDL Is Dangerous
Excess LDL can:
- Narrow your arteries (atherosclerosis)
- Reduce blood flow to the heart and brain
- Lead to heart attacks, strokes, and blocked arteries
Ideal LDL Levels
- Healthy adults: Below 3.4 mmol/L
- Higher-risk individuals (e.g., diabetes, hypertension): Below 2.6 mmol/L
- Heart disease patients: Below 1.8 mmol/L, per cardiology guidelines
Causes of High LDL
- Diet high in saturated and trans fats
- Genetics (e.g., familial hypercholesterolemia)
- Lack of physical activity
- Diabetes or obesity
- Hypothyroidism
- Chronic kidney disease
3. Triglycerides - The Often-Forgotten Factor
Even though not technically “cholesterol,” triglycerides are another blood fat that plays a major role in cardiovascular health.
High triglycerides contribute to:
- Fatty liver
- Pancreatitis
- Insulin resistance
- Higher LDL and lower HDL levels
Optimal level: Below 1.7 mmol/L
Why Cholesterol Levels Matter So Much
High LDL and low HDL silently damage your arteries over years. Most people feel perfectly healthy until a major event happens, which is why cholesterol screening is a key part of preventive health in Singapore.
Regular cholesterol screening tests helps detect risk early so you can make lifestyle changes or receive treatment to prevent complications.
Singapore health data shows:
- High cholesterol rises sharply after age 40
- Men tend to develop cholesterol issues earlier than women
- Many cases of high cholesterol remain undiagnosed until screening
How to Improve Your HDL and Lower LDL
Lifestyle Measures
- Increase physical activity
- Reduce saturated fats (pork lard, fatty meats, butter, pastries)
- Avoid trans fats (fried foods, processed snacks)
- Add healthy fats - olive oil, nuts, salmon
- Increase fibre - vegetables, fruits, oats
- Maintain a healthy weight
- Quit smoking
- Limit alcohol
Medical Treatments (When Needed)
Doctors in Singapore commonly prescribe cholesterol medications such as:
- Statins - lower LDL effectively
- Ezetimibe - reduces cholesterol absorption
- PCSK9 inhibitors - for resistant or genetic cases
Your GP Clinic will decide the best option after reviewing your blood test results, age, family history, and overall risk profile.
How Often Should You Check Your Cholesterol?
MOH Singapore recommends:
Every 1–3 years for adults aged 18 and above
Annually for those with:
- Diabetes
- Hypertension
- Obesity
- Family history of heart disease
- A previous abnormal cholesterol result
Regular health screening allows early intervention before complications develop.
Consult a Doctor Regarding Your High Cholesterol
HDL and LDL cholesterol are more than just numbers on a report, they are powerful predictors of your long-term heart health. By understanding what they mean and how they affect your body, you can take proactive steps to protect your heart.
Whether you're in your 20s or 60s, screening early and regularly is one of the simplest ways to prevent heart disease, still the leading cause of death in Singapore.
Manage High Cholesterol with Regis Medical
Patient-first, Holistic, Dedicated Healthcare
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