What is Cholesterol? Everything About HDL and LDL Cholesterol

Laura ContrerasOrthomolecular Gut Therapist10 december 20247 min. reading time

The word 'cholesterol' often immediately brings up associations. You might also have a negative association with it. But is cholesterol good, bad, dangerous, helpful, or a bit of everything? When should you be concerned about high cholesterol?

What is Cholesterol?

Cholesterol is a fatty substance that your body produces itself and is present in every cell of your body. Although it is often seen as a culprit, cholesterol is indispensable for your body. You need it for example for:

The production of hormones: it is a building block for hormones such as oestrogen, testosterone, and cortisol. These hormones are important for your metabolism and reproduction.
The construction of your cell membranes: cholesterol provides strength and flexibility in your cells and ensures that your cells can function properly.
The production of bile acids: bile acids are important for digesting and absorbing fats from your diet.
The production of vitamin D: you also need cholesterol for the production of vitamin D. Vitamin D is important for the bones and the immune system. Want to know more? Read here everything about vitamin D.

So, cholesterol is actually more your friend than your enemy, unless the balance is disturbed. This happens, for example, when you have too much oxidised LDL and therefore run more risks of health problems.

How is Cholesterol Produced

Did you know that about 75% of your cholesterol is produced by your liver? Only 25% comes from food. This explains why a healthy diet is important, but not the only factor.

Your liver precisely regulates how much cholesterol your body needs. If you consume more cholesterol through food, your liver automatically produces less. But in some people, this mechanism can become disrupted, for example by:

Stress. Chronic stress can increase your cholesterol. It is increasingly proven that cholesterol levels are higher with stress.
An unhealthy lifestyle. Unhealthy diet, little exercise, and smoking cause many disruptions.
Genetic predisposition. Hereditary factors can cause your body to naturally produce a lot of cholesterol.

If your body becomes unbalanced, your cholesterol can rise as a result.

HDL versus LDL: Good and Bad Cholesterol

Cholesterol is often divided into 'good' and 'bad'. But what does that actually mean?

HDL (High-Density Lipoprotein) cholesterol is known as the 'good cholesterol'. It helps return excess cholesterol from your blood vessels back to your liver. In your liver, it is broken down.
LDL (Low-Density Lipoprotein) cholesterol is called the 'bad cholesterol'. LDL transports cholesterol to your cells. If there is too much LDL in your blood, it can accumulate in your blood vessels. This does the opposite of HDL cholesterol. However, LDL cholesterol in itself is not necessarily 'bad'. It plays an important role in transporting cholesterol to cells where it is needed. The problem only arises when LDL becomes damaged by oxidation.

/enThe Difference Between LDL and Oxidised LDL

Free radicals (harmful substances that can cause inflammation or damage) can damage your LDL cholesterol. This damaged LDL is called oxidised LDL. That is where more risks arise.

This oxidation occurs more often with an unhealthy lifestyle, for example through:

Smoking
Unhealthy diet (think of sugar-rich and processed products)

The problem is therefore not necessarily in LDL itself, but in how healthy your LDL is and how much it becomes oxidised. To prevent oxidation of LDL, you can focus on a diet rich in antioxidants: vegetables, fruits, nuts, and seeds. These substances help neutralise the free radicals in your body, making them no longer harmful.

The Role of Inflammation

High cholesterol is often directly linked to cardiovascular diseases, but there is another important factor: inflammation.

When the inside of your blood vessels becomes damaged, your body sends (LDL) cholesterol to the site to repair the damage. Cholesterol acts as a sort of plaster on the 'wound'. The vessel wall can be damaged by, for example, high blood pressure, inflammation, smoking, or stress.

If you suffer from chronic inflammation, your body continues to make repairs and plaques can form. The plaques can lead to narrowing in your blood vessels and pose many risks. So, it is not only high cholesterol that is dangerous, but also the presence of (long-term) inflammation.

What Can You Do to Reduce Inflammation?

Limit inflammation as much as possible: do not sit still for too long, keep stress under control, and limit foods that can cause inflammation (such as sugars and trans fats).
Keep your blood sugar level stable. Fluctuations in your blood sugar increase inflammation. Therefore, choose carbohydrates with a low glycaemic index, such as sweet potatoes, quinoa, or whole grains.
Ensure an anti-inflammatory diet rich in omega-3 fatty acids (oily fish), antioxidants (for example from vegetables, fruits, and fresh herbs), and fibres.

What Do Your Cholesterol Levels Mean?

When you have your cholesterol measured, you usually get an overview of three values:

Total cholesterol level: This is the sum of all types of cholesterol together
HDL cholesterol: Helps transport cholesterol to the liver, where it can be broken down.
LDL cholesterol: Transports cholesterol to the cells, but can be problematic if it becomes oxidised.

Your cholesterol levels are measured in millimoles per litre of blood (mmol/L). For adults, the following guidelines currently apply:

Total cholesterol: Less than 5 mmol/L is considered healthy
HDL cholesterol: More than 1 mmol/L for men and 1.2 mmol/L for women is desired
LDL cholesterol: Less than 3 mmol/L is ideal

When is your cholesterol too high? High cholesterol means that your LDL cholesterol level is higher than 3 mmol/L or that your total cholesterol is higher than 5 mmol/L. This increases the risk of problems such as heart attacks or strokes.

The Influence of Age and Heredity on Your Cholesterol

Your cholesterol levels change over the years. As you get older, your LDL cholesterol can increase, while HDL cholesterol can decrease. This is because your metabolism slows down and your body has more difficulty breaking down excess cholesterol.

In addition, heredity also plays a role. With familial hypercholesterolemia, your LDL cholesterol is naturally higher.

If you are over 40 years old, have an unhealthy lifestyle, or have a family history of cardiovascular diseases, it is wise to regularly check your cholesterol. Your GP can easily measure your cholesterol through a blood test.

How to Keep Your Cholesterol Healthy?

The good news is that you can influence your cholesterol levels yourself. Here are a few smart tips:

Eat Plenty of Antioxidants and Fibres

We already mentioned how important antioxidants are to protect your LDL from oxidation. Antioxidants can be obtained through food: think of vitamin C in vegetables and fruits or vitamin E from nuts and seeds. In addition, dietary fibres from, for example, vegetables, fruits, or beans are important. Fibres bind to cholesterol in your intestines and help remove it from your body.

Healthy Fats Over Trans Fats

Healthy fats such as those in olive oil, avocado, and nuts, increase your HDL cholesterol and reduce inflammation. At the same time, avoid trans fats from fast food and processed products. Trans fats increase LDL and lower your HDL.

Limit Sugars and Fast Carbohydrates

A high blood sugar level increases the risk of inflammation and oxidation of LDL cholesterol. Therefore, avoid fast sugars and opt for, for example, sweet potatoes or quinoa.

Exercise a Lot

Sitting is the new smoking. Sitting still for too long increases inflammation in your body. Therefore, try to walk, cycle, or exercise for at least 30 minutes every day and never sit still for more than an hour.

Sleep and Stress

Lack of sleep and a lot of stress increase inflammation and can also contribute to increased cholesterol. Ensure 7-8 hours of sleep per night and keep your stress under control. Find ways that work for you to manage stress, such as breathing exercises, walking, or yoga.

Good to Know

Cholesterol is not your enemy - it is an important and indispensable substance in your body. Problems arise when your cholesterol levels become unbalanced or when your LDL cholesterol becomes oxidised. Inflammation plays an important role in this and deserves attention in the discussion about cardiovascular diseases.

You can do a lot yourself to keep your cholesterol levels healthy: exercising a lot, eating healthily, and keeping stress under control are all very important.

If you have questions about your cholesterol or want to know if you are at risk of high cholesterol, contact a health professional to have your levels measured and look for a solution together. This is an informative article and does not replace medical advice.

Sources

Maduka IC, Neboh EE, Ufelle SA. The relationship between serum cortisol, adrenaline, blood glucose and lipid profile of undergraduate students under examination stress. Afr Health Sci. 2015;15(1):131-136. doi:10.4314/ahs.v15i1.18
Muldoon MF, Bachen EA, Manuck SB, Waldstein SR, Bricker PL, Bennett JA. Acute cholesterol responses to mental stress and change in posture. Arch Intern Med. 1992;152(4):775-780.
Hong CG, Florida E, Li H, Parel PM, Mehta NN, Sorokin AV. Oxidized low-density lipoprotein associates with cardiovascular disease by a vicious cycle of atherosclerosis and inflammation: A systematic review and meta-analysis. Front Cardiovasc Med. 2023;9:1023651. Published 2023 Jan 16. doi:10.3389/fcvm.2022.1023651
Holvoet P, Mertens A, Verhamme P, et al. Circulating oxidized LDL is a useful marker for identifying patients with coronary artery disease. Arterioscler Thromb Vasc Biol. 2001;21(5):844-848. doi:10.1161/01.atv.21.5.844
Singh N, Singh N, Kumar Singh S, Kumar Singh A, Kafle D, Agrawal N. Reduced Antioxidant Potential of LDL Is Associated With Increased Susceptibility to LDL Peroxidation in Type II Diabetic Patients. Int J Endocrinol Metab. 2012;10(4):582-586. doi:10.5812/ijem.5029
VALENZUELA, ALFONSO, SANHUEZA, JULIO, & NIETO, SUSANA. (2003). Cholesterol oxidation: Health hazard and the role of antioxidants in prevention. Biological Research, 36(3-4), 291-302. https://dx.doi.org/10.4067/S0716-97602003000300002
Feingold KR, Grunfeld C. The Effect of Inflammation and Infection on Lipids and Lipoproteins. [Updated 2022 Mar 7]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK326741/
Vaccarezza M, Galassi FM. Inflammation Beats Cholesterol: A Comment on the Unequivocal Driver of Cardiovascular Disease Risk. J Clin Med. 2023;12(7):2519. Published 2023 Mar 27. doi:10.3390/jcm12072519
Allison MA, Jensky NE, Marshall SJ, Bertoni AG, Cushman M. Sedentary behavior and adiposity-associated inflammation: the Multi-Ethnic Study of Atherosclerosis. Am J Prev Med. 2012;42(1):8-13. doi:10.1016/j.amepre.2011.09.023