Why your GP checks your cholesterol

Cholesterol is a fatty substance your body needs. It helps build cell membranes, makes vitamin D and produces hormones such as oestrogen and testosterone. The trouble starts when there is more of it circulating in your blood than your arteries can comfortably handle, particularly the type carried by low-density lipoprotein (LDL). Over time, excess LDL can settle into the walls of your arteries, narrowing them and raising your risk of a heart attack or stroke.

That is why cholesterol is checked so often. It is a routine part of an NHS Health Check, a long-term condition review, or a general check-up when your GP wants a fuller picture of your heart health. Usually it is measured alongside blood pressure, blood sugar, kidney and liver function, because no single number tells the whole story. Results normally come back in millimoles per litre (mmol/L), which is the standard unit used in the UK.

What each number on your results actually means

A standard lipid profile usually includes several figures. It helps to know what each one is doing:

• Total cholesterol — everything combined: LDL, HDL and other fats. Useful as a headline figure, but it hides important detail.
• LDL cholesterol — often called "bad" cholesterol. This is the one most closely linked to plaque building up in your arteries, and usually the main target for treatment.
• HDL cholesterol — often called "good" cholesterol. It helps carry excess cholesterol back to your liver for disposal, so higher is generally better.
• Non-HDL cholesterol — your total cholesterol minus your HDL. Many clinicians find this the most useful single figure, because it captures all the cholesterol that can damage arteries.
• Triglycerides — another blood fat, closely tied to diet, alcohol and blood sugar control.

Reading the numbers: what counts as healthy

For most adults in the UK, the usual guide figures are:

• Total cholesterol: below 5 mmol/L
• LDL cholesterol: below 3 mmol/L
• HDL cholesterol: above 1.0 mmol/L for men and above 1.2 mmol/L for women
• Non-HDL cholesterol: below 4 mmol/L
• Triglycerides: below 1.7 mmol/L
• Total cholesterol to HDL ratio: below 4

These are sensible targets for a generally healthy person, but they are not rules set in stone. If you already have heart disease, diabetes, kidney disease or a strong family history, your GP may want your LDL considerably lower — sometimes below 2.6, or even below 1.8 mmol/L. One reading on its own is also just a snapshot. Illness, stress, pregnancy, an injury or a recent infection can all nudge your figures temporarily, which is why a repeat test is often arranged before any decisions are made.

When one number isn't the whole story

A cholesterol result never exists in isolation. Your GP will weigh it against your age, sex, blood pressure, smoking status, weight and family history, often using a risk calculator to estimate your chance of a cardiovascular event over the next ten years. Two people with identical cholesterol readings can receive very different advice because of these other factors.

Family history deserves particular attention. If a close relative developed heart disease before the age of 60, or if your cholesterol is unexpectedly high despite a healthy lifestyle, your GP may suspect familial hypercholesterolaemia (FH), an inherited condition affecting around one in 250 people in the UK. Identifying it matters, because treatment is highly effective and relatives can be tested too.

Everyday changes that genuinely shift your numbers

The good news is that diet and lifestyle can move cholesterol meaningfully, often within eight to twelve weeks. Practical steps include:

• Cut back on saturated fat. Butter, cream, fatty cuts of meat, pastries, hard cheese and coconut oil are the biggest dietary drivers of LDL. Swapping to olive or rapeseed oil, leaner meats and lower-fat dairy makes a real difference.
• Eat more soluble fibre. Oats, barley, beans, lentils, chickpeas, apples and pears bind cholesterol in the gut. Aim for 30g of fibre a day, building up gradually.
• Try plant stanols and sterols. Found in fortified yoghurts, spreads and drinks, around 2–3g daily can lower LDL by roughly 10 per cent.
• Include oily fish twice a week. Salmon, mackerel, sardines or trout help with triglycerides. If you don't eat fish, your GP can advise on alternatives.
• Move more. Around 150 minutes of moderate activity weekly — brisk walking counts — raises HDL and helps with weight and blood pressure.
• Watch alcohol, smoking and sleep. Regular heavy drinking pushes triglycerides up, smoking lowers HDL, and poor sleep tends to worsen the whole picture.

Talking through your results with your GP or practice nurse

It is worth booking a review rather than simply filing the printout away. Ask what your personal target is, whether a repeat test is needed, and how much your lifestyle changes are likely to achieve on their own. If medication such as a statin is suggested, ask about the benefits for someone with your level of risk, and about side effects — most people tolerate them well, and there are several options if one doesn't suit you.

Never stop a prescribed cholesterol medicine without speaking to your GP first, even if your numbers have improved. That improvement is often the treatment working. If your results are borderline, a three-month trial of diet and exercise with a follow-up blood test is a reasonable and very common plan. Bring your questions, however small — understanding your own numbers is one of the most useful things you can do for your long-term heart health.