Heart Health

Cholesterol: Complete Understanding Guide

Cholesterol testing is one of the most common blood tests, but the results confuse many patients. This guide clearly explains what each number means and what to do about it.

Total cholesterol target
<5.0 mmol/L (general)
LDL (bad)
Lower is better
HDL (good)
Higher is better
Triglycerides
<1.7 mmol/L

Understanding Each Component

ComponentWhat It MeansTarget
Total cholesterolSum of all cholesterol types<5.0 mmol/L (general population)
LDL (low-density lipoprotein)'Bad' cholesterol — deposits in artery walls<3.0 mmol/L (general); <1.8 mmol/L (very high risk)
HDL (high-density lipoprotein)'Good' cholesterol — removes cholesterol from arteriesHigher is better; >1.0 mmol/L (men), >1.2 mmol/L (women)
TriglyceridesBlood fats related to diet and metabolic health<1.7 mmol/L
Non-HDL cholesterolTotal minus HDL — increasingly used as primary target<4.0 mmol/L (general)

Familial Hypercholesterolaemia — When Genetics Matter

About 1 in 250 people have familial hypercholesterolaemia, a genetic condition causing very high LDL cholesterol from birth and significantly increased early heart disease risk. Clues include: total cholesterol >7.5 mmol/L, family history of early heart attacks, or physical signs like tendon xanthomas (cholesterol deposits). This requires specialist referral and often statin treatment from a young age.

Lifestyle vs Medication

ApproachTypical LDL Reduction
Diet changes (Mediterranean, reduced saturated fat)10-20%
Weight loss (if overweight)5-10%
ExerciseModest LDL effect; more effect on HDL and triglycerides
Statins (standard dose)30-50%
Statins (high dose) + ezetimibeUp to 65-70%
PCSK9 inhibitors (injectable)Additional 50-60% on top of statins — for very high risk
Your Overall Risk Matters More Than a Single NumberCholesterol targets are increasingly individualised based on your overall cardiovascular risk (calculated using tools like QRISK3) rather than a one-size-fits-all number — someone with diabetes or existing heart disease needs much lower LDL targets than someone with no other risk factors.
Is high HDL always good?
Generally yes, but extremely high HDL (>2.3 mmol/L) has been associated with some unexpected outcomes in certain studies — the relationship isn't perfectly linear, though moderate-high HDL remains protective for most people.
Do eggs raise cholesterol?
For most people, dietary cholesterol (from eggs, shellfish) has a smaller effect on blood cholesterol than saturated and trans fats — moderate egg consumption is not significantly harmful for most people.
Can cholesterol be too low?
Extremely low cholesterol is rare and usually only seen with certain medical conditions or very restrictive diets/malabsorption — for most people on statins, lower is better within recommended treatment ranges.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.