When most people talk about cholesterol, they focus on whether it is “high” or “low.”
Doctors today emphasize that what truly matters is how your different cholesterol types balance each other.

Even with a normal total cholesterol level, certain ratios and a hidden form called remnant cholesterol can quietly increase your risk of heart disease and stroke.

The Four Cholesterol Numbers

General Principle

While a normal Total Cholesterol (TC) level is a good starting point, cardiovascular risk is better assessed by the balance of different cholesterol types. Doctors and researchers emphasize specific ratios and a hidden form of fat called Remnant Cholesterol (RC) because elevated levels can increase the risk of heart disease and stroke, even with a normal TC.

The Cholesterol Ratios (Low-Risk Thresholds)

The thresholds listed below are generally considered desirable for a lower-risk profile, but the “ideal” number for any individual should be determined by a doctor based on their complete medical history.

• Total Cholesterol to HDL (TC/HDL)
  • Formula: TC $÷$ HDL
  • Low-Risk Threshold: Below 4.5
  • Higher ratios are linked with greater stroke and heart disease risk. For very low risk, many experts prefer a ratio below $3.5$.
• LDL to HDL (LDL/HDL)
  • Formula: LDL $÷$ HDL
  • Low-Risk Threshold: Below 3.0
  • A high ratio predicts an increased risk of coronary artery disease.
• Triglycerides to HDL (TG/HDL)
  • Formula: TG $÷$ HDL
  • Low-Risk Threshold: Below 1.8
  • This ratio is a strong marker for insulin resistance and metabolic syndrome. Ratios above $1.8$ are associated with higher risks of heart attack and stroke.
• Remnant Cholesterol (RC)
  • Formula: $\text{TC}-\text{LDL}-\text{HDL}$
  • Low-Risk Threshold (Research-Based): Below $30\text{ mg/dL}$ ($0.8\text{ mmol/L}$)
  • RC is the cholesterol carried in triglyceride-rich lipoproteins. While research consistently shows that a level above $30\text{ mg/dL}$ is a significant, independent predictor of cardiovascular risk, this threshold is not yet a universally adopted clinical guideline or treatment target established by major medical associations.
  • Note that the formula $\text{RC}=\text{TC}-\text{LDL}-\text{HDL}$ is an estimation that is less reliable when triglycerides are very high (above $400\text{ mg/dL}$).

Example Calculation

If your lab report shows:

• Total Cholesterol = 220 mg/dL
• LDL = 130 mg/dL
• HDL = 50 mg/dL
• Triglycerides = 150 mg/dL

then:

The interpretation remains that the elevated triglyceride and remnant cholesterol levels signal a higher risk, despite the normal individual TC and healthy TC/HDL and LDL/HDL ratios.

Evidence from Clinical Studies

• Total/HDL ratio: The Stroke study by Zhang Y et al. (2012) linked higher ratios with increased ischemic stroke risk.

• LDL/HDL ratio: Yu C et al. (2025) found that a higher ratio predicted first stroke and coronary heart disease in adults with hypertension.

• TG/HDL ratio: The Diabetology & Metabolic Syndrome cohort (2024) showed a nonlinear relationship; risk rose sharply below 1.85 then plateaued.

• Remnant cholesterol: Research in Atherosclerosis (2024), Arteriosclerosis Thrombosis & Vascular Biology (2022, 2024), and Journal of the American Heart Association (2025) confirms that high RC predicts both heart attack and ischemic stroke, independent of LDL.

How to Improve Your Ratios

• Eat more fiber-rich foods, seafood, poultry, and adequate portions of meat.
• Choose low-glycemic fruits such as apples, berries, or guava; limit very sweet ones.
• Avoid added sugars and sweetened drinks.
• Exercise for at least 30 minutes most days of the week.
• Do not smoke and keep alcohol intake to a minimum.
• Take any lipid-lowering or triglyceride-lowering medication exactly as prescribed by your doctor.

These steps raise HDL, lower LDL and triglycerides, and help restore a healthy cholesterol balance.

What This Means for You

You can have normal cholesterol yet still face a higher risk of heart disease and stroke if your ratios or remnant cholesterol are off balance.

At your next check-up, ask your doctor: “Can we check my cholesterol ratios and remnant cholesterol?”

Those simple calculations can reveal risks that total cholesterol alone may hide.

References

1. Zhang Y et al. Total and High-Density Lipoprotein Cholesterol and Stroke Risk. Stroke 2012.

2. Yu C et al. LDL/HDL Ratio and First Stroke. Hypertension Cohort 2025.

3. Zhang S et al. Triglyceride/HDL Ratio and Stroke Risk. Diabetology & Metabolic Syndrome 2024.

4. Packard C J et al. Remnants, LDL, and Lipoprotein-Related Risk. Arterioscler Thromb Vasc Biol 2022.

5. Han M et al. High Remnant Cholesterol and Stroke Risk. Atherosclerosis 2024.

6. Wang D et al. Remnant Cholesterol and Cardiovascular Risk. J Am Heart Assoc 2025.