Cholesterol Results Explained: LDL, HDL, Triglycerides and Your Heart Risk

Cholesterol is one of the most talked-about health markers, yet many people receive their results without a clear explanation of what each number means. This guide breaks down your cholesterol panel — total cholesterol, LDL, HDL, and triglycerides — and explains what your results mean for your heart health.

What Is Cholesterol?

Cholesterol is a fatty substance (lipid) found in your blood and in every cell of your body. Despite its bad reputation, cholesterol is essential — your body needs it to make hormones, vitamin D, and the bile acids that help digest fat. The problem arises when certain types of cholesterol build up in your arteries, narrowing them and increasing the risk of heart attack and stroke.

Cholesterol is transported through the bloodstream by proteins called lipoproteins. The main types are LDL (low-density lipoprotein) and HDL (high-density lipoprotein), and understanding the difference between them is key to interpreting your results.

Components of a Cholesterol (Lipid Profile) Test

Total Cholesterol

This is the overall amount of cholesterol in your blood, measured in millimoles per litre (mmol/L). In the UK, a total cholesterol below 5.0 mmol/L is generally considered desirable for the general population. However, total cholesterol alone is a relatively poor predictor of heart risk — the breakdown into LDL and HDL is far more informative.

LDL Cholesterol ("Bad" Cholesterol)

LDL carries cholesterol from the liver to the cells. When there is too much LDL in the blood, it can deposit cholesterol in the walls of arteries, forming plaques that narrow and harden the arteries — a process called atherosclerosis. This is why LDL is often referred to as "bad" cholesterol.

LDL Level	Interpretation
Below 3.0 mmol/L	Desirable (general population)
Below 2.0 mmol/L	Target for people at high cardiovascular risk
Below 1.4 mmol/L	Target for people with established heart disease or diabetes
3.0–4.9 mmol/L	Borderline high
5.0 mmol/L or above	High — discuss with your GP

HDL Cholesterol ("Good" Cholesterol)

HDL carries cholesterol away from the arteries and back to the liver, where it is broken down and removed from the body. Higher HDL levels are protective against heart disease — this is why HDL is called "good" cholesterol.

• Men: HDL above 1.0 mmol/L is desirable; above 1.4 mmol/L is optimal.
• Women: HDL above 1.2 mmol/L is desirable; above 1.6 mmol/L is optimal.
• HDL below 1.0 mmol/L in men or below 1.2 mmol/L in women is associated with increased heart risk.

HDL is raised by regular aerobic exercise, moderate alcohol consumption (within safe limits), stopping smoking, and a diet rich in healthy fats (olive oil, oily fish, nuts).

Non-HDL Cholesterol

Non-HDL cholesterol = Total cholesterol minus HDL. This is increasingly used as a cardiovascular risk marker because it captures all the "bad" lipoproteins in a single number. The UK target for the general population is below 4.0 mmol/L, and below 2.5 mmol/L for high-risk individuals.

Triglycerides

Triglycerides are another type of fat in the blood. After you eat, your body converts the calories it doesn't immediately need into triglycerides, which are stored in fat cells. Persistently raised triglycerides increase your cardiovascular risk and can cause pancreatitis at very high levels.

Triglyceride Level (fasting)	Interpretation
Below 1.7 mmol/L	Normal
1.7–2.2 mmol/L	Mildly elevated
2.3–5.6 mmol/L	Moderately elevated — lifestyle changes needed
Above 5.6 mmol/L	Significantly elevated — discuss urgently with your GP

Common causes of raised triglycerides include a diet high in refined carbohydrates and sugar, alcohol excess, obesity, type 2 diabetes, underactive thyroid, and some medications.

Total Cholesterol:HDL Ratio

Some labs report this ratio, which divides your total cholesterol by your HDL. A lower ratio is better. A ratio below 4 is generally considered good; above 6 indicates increased cardiovascular risk.

What Is a Cardiovascular Risk Score?

Your individual cholesterol numbers must be interpreted alongside your overall cardiovascular risk. UK GPs use tools such as QRISK3 to calculate your 10-year risk of having a heart attack or stroke. This takes into account your age, sex, blood pressure, cholesterol, smoking status, diabetes, family history, ethnicity, and other factors.

If your 10-year risk is 10% or above, your GP is likely to discuss statin therapy alongside lifestyle changes, regardless of your absolute cholesterol numbers. Some people with high risk need statins even if their cholesterol appears only mildly elevated.

How to Improve Your Cholesterol

Lifestyle changes can significantly improve your cholesterol profile:

• Diet: Reduce saturated fat (red meat, full-fat dairy, butter, coconut oil) and replace with unsaturated fats (olive oil, avocados, oily fish, nuts). Increase soluble fibre (oats, beans, lentils, fruit). Reduce refined sugar and processed foods to lower triglycerides.
• Exercise: Regular aerobic exercise (brisk walking, cycling, swimming) raises HDL and lowers triglycerides. Aim for at least 150 minutes per week.
• Smoking: Stopping smoking raises HDL and reduces overall cardiovascular risk substantially.
• Alcohol: Reducing alcohol intake lowers triglycerides.
• Statins: If lifestyle changes are insufficient or your risk is high, statins (e.g., atorvastatin, rosuvastatin) are very effective at lowering LDL and reducing cardiovascular events.

Familial Hypercholesterolaemia (FH)

Familial hypercholesterolaemia is an inherited condition causing very high LDL cholesterol from birth. It affects around 1 in 250 people in the UK and significantly increases the risk of early heart disease if untreated. It is often suspected when LDL is above 5.0 mmol/L, especially if there is a strong family history of early cardiovascular disease. If FH is suspected, your GP may refer you to a lipid clinic.