Low-density lipoprotein (LDL) is commonly known as 'bad cholesterol’ — but this is overly simplistic as it's essential for your health. But when your levels become too high, it can increase your risk of serious health conditions. Keep reading to learn about LDL, how often to check your levels, and tips for lowering them if they’re too high.

How is LDL cholesterol made?

Your liver makes LDL cholesterol, which forms part of your total cholesterol. Learn more about the different types of cholesterol.

What does LDL cholesterol do?

LDL forms a rim around cholesterol to transport it around your body. You need enough LDL cholesterol in your blood, as LDL helps to deliver cholesterol to cells. 

But when you have too much LDL cholesterol in your blood, it can lead to plaque buildup in your blood vessel walls (atherosclerosis). This increases your risk for illnesses — like heart disease and stroke. But it’s important to remember that your risk of developing these diseases is dependent on many other factors, like: 

What’s the normal range for LDL cholesterol?

Ideally, LDL levels should be less than 3mmol/L (millimole a litre) in healthy adults and less than 2mmol/L in those at higher risk.

You can check your LDL levels at home using a cholesterol blood test. If your LDL levels are abnormal, you should check them every three months. Your GP report contains advice on lowering them — like lifestyle and dietary changes. Sometimes you might need medication too.

If you follow a low-carbohydrate, high-fat, or ketogenic diet, you might have higher LDL cholesterol levels.

What causes high LDL cholesterol?

Many things can cause high LDL. These include:

  • a diet high in saturated fats
  • being overweight or obese
  • not doing enough physical activity
  • smoking
  • a genetic condition called familial hypercholesterolemia 
  • some medicines — like steroids 

LDL vs HDL cholesterol 

Another form of cholesterol is high-density lipoprotein or HDL. HDL helps protect against diseases of the arteries.

HDL is one protein that carries fats (lipids) around your body and plays a crucial role in ensuring balanced cholesterol levels.

A cholesterol blood test can measure the ratio between the amount of HDL against your total cholesterol. This is known as the TC:HDL ratio. This is an important marker when determining your future risk of heart disease. 

How to lower your LDL cholesterol

Some lifestyle changes can help you lower your LDL cholesterol. These include:

  • losing weight if you’re overweight
  • following the Mediterranean diet
  • cutting back on your intake of saturated fats
  • quitting smoking
  • exercising regularly — always check with your doctor before increasing frequency and intensity
  • reducing your intake of refined sugars and high fructose foods — opt for wholegrain carbohydrates high in fibre
  • limiting your intake of trans fats — found in highly processed foods
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Dansinger, M. L., Williams, P. T., Superko, H. R., & Schaefer, E. J. (2019). Effects of weight change on apolipoprotein B-containing emerging atherosclerotic cardiovascular disease (ASCVD) risk factors. Lipids in health and disease, 18(1), 1-10.

Howard, B. V., Robbins, D. C., Sievers, M. L., Lee, E. T., Rhoades, D., Devereux, R. B., ... & Howard, W. J. (2000). LDL cholesterol as a strong predictor of coronary heart disease in diabetic individuals with insulin resistance and low LDL: The Strong Heart Study. Arteriosclerosis, thrombosis, and vascular biology, 20(3), 830-835.

National Health Services (2020). Overview: Coronary Heart Disease. Retrieved 11 October 2022 from https://www.nhs.uk/conditions/coronary-heart-disease/

Palazhy, S., Kamath, P., & Vasudevan, D. M. (2014). Estimation of Small, Dense LDL particles using equations derived from routine lipid parameters as surrogate markers. Biochemistry and Analytical Biochemistry, 3(1), 1.

Richardson, T. G., Sanderson, E., Palmer, T. M., Ala-Korpela, M., Ference, B. A., Davey Smith, G., & Holmes, M. V. (2020). Evaluating the relationship between circulating lipoprotein lipids and apolipoproteins with risk of coronary heart disease: A multivariable Mendelian randomisation analysis.PLoS medicine,17(3), e1003062.

Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Curr Atheroscler Rep. 2010 Nov;12(6):384-90. doi: 10.1007/s11883-010-0131-6. PMID: 20711693; PMCID: PMC2943062.