Understanding high cholesterol: Causes, risks and when to act

What causes high cholesterol?

High cholesterol is common in the UK and often has multiple contributing factors. If you’re searching for “what causes high cholesterol,” it helps to think in terms of lifestyle, medical conditions and genetics. Early understanding lets you take sensible steps — from diet and exercise to consulting your GP about testing and treatment.

For broader context on supplements and products marketed to support cholesterol and heart health, see our Cholibrium reviews and resources page.

How cholesterol works (briefly)

Cholesterol is a waxy substance the body needs for cell membranes and hormone production. It travels in the blood attached to proteins in particles called lipoproteins: low‑density lipoprotein (LDL) and high‑density lipoprotein (HDL). Clinicians typically focus on reducing high LDL and triglycerides while supporting healthy HDL levels. Tests from your GP or a clinic will report these values and total cholesterol.

Main causes of high cholesterol

• Dietary patterns: Diets high in saturated fat and trans fats (found in some processed foods and fried items) can raise LDL cholesterol. Overeating and diets very high in refined carbohydrates and sugars may raise triglycerides.
• Physical inactivity and weight: Being overweight or inactive can lower HDL (the ‘good’ cholesterol) and raise LDL and triglycerides.
• Age and sex: Cholesterol tends to rise with age. Before the menopause, women often have lower LDL than men of the same age, but levels can increase after menopause.
• Genetics: Familial hypercholesterolaemia (FH) and other inherited conditions can cause very high cholesterol regardless of lifestyle. A family history of early heart disease is a red flag.
• Medical conditions: Type 2 diabetes, hypothyroidism, chronic kidney disease and certain liver conditions can affect cholesterol levels.
• Medications and substances: Some medicines (for example certain steroids, antipsychotics or immunosuppressants) can raise cholesterol. Excess alcohol intake can increase triglycerides.
• Smoking: Smoking does not directly raise LDL in all people, but it damages blood vessels and lowers HDL, increasing cardiovascular risk.

Risks associated with high cholesterol

High LDL and triglycerides are linked to an increased risk of atherosclerosis — the build‑up of fatty plaques in arteries — which can lead to coronary heart disease, stroke and peripheral arterial disease. Risk depends on overall cardiovascular risk profile: blood pressure, age, smoking, diabetes and family history all matter.

Clinicians assess risk using calculators (such as QRISK2 in the UK) to determine if lifestyle changes alone are enough or if medication may be recommended.

When to act and how to get tested

If you have risk factors (family history of early heart disease, long‑standing diabetes, obesity, smoking, high blood pressure, or symptoms such as chest pain), speak to your GP. Many people have their cholesterol checked as part of a NHS health check or during routine blood tests. The usual test is a fasting or non‑fasting lipid profile reporting total cholesterol, LDL, HDL and triglycerides.

Act sooner if you have known familial hypercholesterolaemia or multiple risk factors. Even modest improvements in diet, activity and weight can reduce your risk over time.

Practical steps to manage cholesterol

Most guidance focuses on combined lifestyle measures and, where appropriate, medication under medical supervision.

• Dietary changes: Reduce foods high in saturated and trans fats; increase oily fish (for omega‑3s), fibre‑rich foods (oats, beans, vegetables), nuts and plant stanols/sterols where appropriate. Wholefood approaches — Mediterranean‑style diets — are often recommended.
• Physical activity: Aim for at least 150 minutes of moderate activity each week and include muscle‑strengthening activities twice weekly if able.
• Lose excess weight: Even a small reduction in body weight can improve lipid levels.
• Quit smoking & moderate alcohol: Stopping smoking and limiting alcohol to recommended limits help reduce overall cardiovascular risk.
• Medication where needed: Statins are the most commonly prescribed drugs to lower LDL cholesterol. Other agents, including ezetimibe and newer therapies, may be used in some patients. Only start or stop medications after discussion with your GP or specialist.

What about supplements and mushroom products?

Some supplements and botanicals are marketed as supporting healthy cholesterol levels or heart function. For example, products such as Cholibrium are marketed as supporting healthy heart function and maintaining cholesterol levels within a healthy range; the maker highlights a formula of mushroom extracts (including reishi, shiitake, cordyceps and others) and refers to traditional use and research. It’s important to note that manufacturers’ claims are not the same as proven clinical evidence of benefit, and supplements are regulated differently from medicines in the UK.

If you are considering any supplement, tell your GP or pharmacist — especially if you take prescribed medicines such as statins, as interactions or unexpected effects can occur. Your clinician can help weigh potential benefits, the quality of evidence and safety for your situation.

When to see a healthcare professional

See your GP if you have:

• a family history of early heart disease or diagnosed familial hypercholesterolaemia;
• persistently high cholesterol on tests;
• other cardiovascular risk factors such as diabetes, high blood pressure or smoking;
• symptoms suggestive of heart or circulation problems (chest pain, breathlessness, leg pain when walking).

Regular check‑ups and an honest discussion about lifestyle, risk and treatment options are the best way to manage high cholesterol effectively and reduce long‑term risk.

Medical disclaimer: This article is for informational purposes only and does not replace professional medical advice. Consult your GP for personalised guidance.

Related reading

• Cholibrium review: full verdict
• How natural compounds lower cholesterol: Science-backed mechanisms
• How to choose a cholesterol supplement: A practical buyer’s guide