Why Cholesterol Matters More Than You Think
Cholesterol is one of the most misunderstood markers on a blood test. For decades, the prevailing message was simple: high cholesterol is bad, low cholesterol is good. But the reality is far more nuanced. Understanding your full lipid panel — not just total cholesterol — gives you a much clearer picture of your cardiovascular risk and overall metabolic health.
In Australia, cardiovascular disease remains the leading cause of death, claiming approximately 42,000 lives each year. Yet a simple fasting lipid panel, tracked over time, can reveal your risk trajectory and guide preventive action years before problems develop.
What Is Cholesterol?
Cholesterol is a waxy, fat-like substance that's essential for life. Your body produces about 80% of the cholesterol it needs — the liver manufactures roughly 1,000mg daily. The remaining 20% comes from dietary sources.
Cholesterol serves critical functions:
- Cell membrane structure: Every cell in your body requires cholesterol for its outer membrane
- Hormone production: Cholesterol is the precursor to testosterone, estrogen, cortisol, and vitamin D
- Bile acid synthesis: Required for fat digestion and absorption
- Brain function: The brain contains ~25% of the body's cholesterol
Since cholesterol can't dissolve in blood (it's a fat), it's transported in protein-wrapped packages called lipoproteins. The type of lipoprotein carrying your cholesterol matters far more than the total amount.
Understanding Your Lipid Panel
Total Cholesterol
Total cholesterol is the sum of all cholesterol in your blood, including LDL, HDL, and VLDL fractions.
- Desirable: < 5.5 mmol/L
- Borderline high: 5.5–6.5 mmol/L
- High: > 6.5 mmol/L
However, total cholesterol alone is a poor predictor of cardiovascular risk. A person with high total cholesterol driven by high HDL is at much lower risk than someone with borderline total cholesterol but very high LDL.
LDL Cholesterol — The Primary Risk Driver
Low-density lipoprotein (LDL) carries cholesterol from the liver to the arteries. When LDL levels are elevated, excess cholesterol can accumulate in arterial walls, forming plaques that narrow and harden arteries (atherosclerosis).
- Optimal: < 2.0 mmol/L (for people at high cardiovascular risk)
- Near optimal: 2.0–2.6 mmol/L
- Borderline high: 2.6–3.4 mmol/L
- High: 3.4–4.1 mmol/L
- Very high: > 4.1 mmol/L
Your target LDL depends on your overall cardiovascular risk profile. People with existing heart disease, diabetes, or multiple risk factors should aim lower than the general population.
HDL Cholesterol — The Protective Factor
High-density lipoprotein (HDL) performs "reverse cholesterol transport" — collecting excess cholesterol from arteries and returning it to the liver for excretion. Higher HDL is generally protective.
- Low (increased risk): < 1.0 mmol/L (men), < 1.3 mmol/L (women)
- Desirable: 1.0–1.5 mmol/L
- Protective: > 1.5 mmol/L
Triglycerides
Triglycerides are the most common type of fat in your body. They're made from calories you eat but don't immediately use, stored in fat cells, and released for energy between meals.
- Normal: < 1.7 mmol/L
- Borderline high: 1.7–2.2 mmol/L
- High: 2.2–5.6 mmol/L
- Very high: > 5.6 mmol/L (risk of pancreatitis)
Elevated triglycerides are strongly associated with metabolic syndrome, insulin resistance, and increased cardiovascular risk. They're often the first lipid marker to respond to dietary changes — particularly reducing refined carbohydrates, sugar, and alcohol.
Non-HDL Cholesterol
Calculated as total cholesterol minus HDL, non-HDL cholesterol captures all the potentially atherogenic (artery-damaging) particles in one number. Many cardiologists now consider it a better risk predictor than LDL alone.
- Desirable: < 3.8 mmol/L
- Optimal for high-risk patients: < 2.5 mmol/L
Beyond the Basics: Advanced Lipid Markers
LDL Particle Number and Size
Not all LDL particles are equal. Research shows that people with many small, dense LDL particles face higher cardiovascular risk than those with fewer, larger LDL particles — even if their total LDL cholesterol is the same. Advanced lipid testing (such as NMR LipoProfile) can measure particle number and size, though it's not routinely ordered in Australia.
Lipoprotein(a) — Lp(a)
Lp(a) is a genetically determined lipoprotein that significantly increases cardiovascular risk. It's not affected by diet or most medications. An estimated 1 in 5 people has elevated Lp(a), yet most have never been tested.
- Desirable: < 75 nmol/L (or < 30 mg/dL)
- High risk: > 125 nmol/L (or > 50 mg/dL)
Lp(a) only needs to be tested once (since it's genetic), but knowing your level can significantly impact risk assessment and treatment decisions.
ApoB (Apolipoprotein B)
Every atherogenic lipoprotein particle carries one ApoB molecule. Measuring ApoB effectively counts the number of potentially harmful particles, making it arguably the single best marker for cardiovascular risk.
- Desirable: < 0.9 g/L
- Optimal: < 0.7 g/L
How TRT Affects Your Cholesterol
For men on testosterone replacement therapy, lipid monitoring is essential because TRT can influence your cholesterol profile in several ways:
- HDL reduction: TRT typically lowers HDL by 5–15%. This is one of the most consistent lipid effects of exogenous testosterone
- LDL changes: Effects on LDL are variable — some studies show modest decreases, others show no change or slight increases
- Triglyceride reduction: TRT often modestly lowers triglycerides, particularly in men with metabolic syndrome
- Total cholesterol: Usually unchanged or slightly reduced
The HDL reduction from TRT means that monitoring your full lipid panel (not just total cholesterol) becomes even more important. Tracking the ratio of triglycerides to HDL and your non-HDL cholesterol over time gives a clearer picture of your cardiovascular trajectory.
Lifestyle Factors That Impact Cholesterol
Diet
Dietary cholesterol (from eggs, shellfish, etc.) has less impact on blood cholesterol than previously believed. The bigger drivers are:
- Saturated fat: Raises LDL in most people. Found in fatty meats, full-fat dairy, coconut oil, and palm oil
- Trans fats: The worst offender — raises LDL and lowers HDL simultaneously. Now largely eliminated from Australian food supply
- Refined carbohydrates: Excess sugar and refined grains raise triglycerides and create small, dense LDL particles
- Fibre: Soluble fibre (oats, legumes, psyllium) lowers LDL by 5–10%
- Omega-3 fatty acids: Fish oil effectively lowers triglycerides, though its effect on cardiovascular outcomes is debated
Exercise
Regular aerobic exercise is one of the most reliable ways to raise HDL. It also modestly lowers LDL and triglycerides. Aim for at least 150 minutes of moderate-intensity exercise per week.
Body Weight
Losing 5–10% of body weight can reduce LDL by 5–8%, triglycerides by 20–30%, and increase HDL by 5–10%. Weight loss often produces more dramatic lipid improvements than dietary changes alone.
Alcohol
Moderate alcohol raises HDL, which partly explains the observed cardiovascular benefit of light drinking. However, excess alcohol significantly raises triglycerides and total cardiovascular risk.
When to Consider Medication
In Australia, the decision to start cholesterol-lowering medication (typically a statin) is based on your overall cardiovascular risk, not just your cholesterol numbers. Your GP can calculate your absolute cardiovascular risk using the Australian CVD Risk Calculator, which factors in age, sex, blood pressure, cholesterol, smoking status, and diabetes.
- Low risk (< 5% in 5 years): Lifestyle changes are the primary approach
- Moderate risk (5–10%): Lifestyle changes with consideration of medication if risk factors persist
- High risk (> 10%): Medication usually recommended alongside lifestyle changes
Statins are the most prescribed cholesterol-lowering drugs and have strong evidence for reducing cardiovascular events. Other options include ezetimibe, PCSK9 inhibitors, and fibrates (for high triglycerides).
Tracking Your Lipids with BloodTrack
A single cholesterol test is useful, but your lipid trend over years is what truly matters. With BloodTrack, you can:
- Visualise all lipid markers — total cholesterol, LDL, HDL, triglycerides, and ratios on one dashboard
- Track the triglyceride-to-HDL ratio — a powerful predictor of insulin resistance and cardiovascular risk (target: < 1.5)
- Monitor TRT effects — see exactly how testosterone therapy is affecting your lipid profile over time
- Measure lifestyle impact — see how dietary changes, exercise, or medication are moving your numbers
- Share with your doctor — export visual reports that show trends, not just isolated numbers
Your cholesterol story is written over years, not in a single test. Start tracking today to understand where your cardiovascular health is heading.