HDL Cholesterol: Is it the hero or the villain?

 

Every great story needs a great hero and a terrific villain. With his evil actions, the villain represents the opposite of the hero, driving him to act and save the day, allowing him to shine. The High-Density Lipoproteins (HDL) play the hero role, and Low-Density Lipoproteins (LDL) play the story's villain. This, however, might not always be the case. It has always been assumed that high LDL levels, known as the "bad" cholesterol, increase a person's heart attack and stroke risk. And, high HDL, or the so called "Good" cholesterol, can help reduce cholesterol levels. As a result, several publications and articles are currently pushing and instructing people on increasing their HDL levels (1). However, we should keep HDL levels within a normal range because sometimes having too much of a good thing might be harmful; it can hurt our bodies and raise the risk of cardiovascular and other diseases rather than improving it, as studies suggest.

From: https://stock.adobe.com/images/cartoon-cholesterol-hdl-and-ldl-components-are-good-fats-and-bad-fats-from-food/289846779

What is HDL?

Before understanding the role of HDL, we need to know what cholesterol is. Cholesterol is a fat-like substance found in all the cells in our body. Our body makes cholesterol, which is required to make hormones, vitamin D, and other essential substances in food digestion. But too much cholesterol is harmful, as it can combine with other substances and stick to the artery wall, forming plaque; the buildup of this plaque is called atherosclerosis. The buildup of plaque is a significant cause of coronary artery disease (CAD), where the coronary artery becomes narrowed or blocked. Cholesterol travels throughout our body via lipoproteins. These lipoproteins are the combination of fat and proteins, HDL, and LDL. The latter is called the "bad" cholesterol, as high plasma levels are responsible for plaque formation. HDL is known as the "good" cholesterol as it carries the "bad" cholesterol back to the liver, where it is broken down and removed from our body. We should maintain both levels within the normal range, even though many people think that the more HDL we have, the better our health outcome. (2)

Why are HDL levels a problem?

HDL is a healthy cholesterol with a favorable purpose in our bodies. This fact, however, has led to various misconceptions: some people believe that the greater the HDL number, the lower the risk of developing cardiovascular disease; others overlook the importance of HDL levels and instead prioritize LDL. The typical range values of HDL lie between 40 mg/dl and 80 mg/dl, not too low to a level that cannot effectively lower the LDL and not too high to increase the risk of heart disease. Moreover, a study of 400,000 people of the general population in the U.K. suggests that men with HDL levels lower than 40 mg/dl or higher than 80 mg/dl and women above 100 mg/dl are at a greater risk of both mortality from all causes, cardiovascular disease in particular. Similar findings were made in people who already had certain risky conditions. Another study of more than 11,000 people with hypertension found a higher risk of cardiovascular events in patients with HDL levels below 40 mg/dl and above 80 mg/dl.(3, 4) To maintain optimal cardiovascular health, HDL levels should fall between 40 mg/dl to 80 mg/dl. Individuals with HDL levels outside this range are at a greater risk of mortality from all causes, particularly cardiovascular disease.

Elevated levels of HDL are also associated with other health issues. A study of more than 16,000 Australians over 70 found that those with the highest HDL levels were at 33% higher risk of bone fractures than those with lower levels, indicating that higher-than-normal HDL levels adversely affect bone density. Observational and genetic studies suggested that high HDL levels are a potential risk factor for Age-related Macular degeneration (AMD: an eye condition that can blur central vision). Some genetic studies found and supported an inverse relationship between HDL levels and infectious diseases. Other studies indicate a possible relationship between HDL levels, dementia, and type 2 diabetes, with the need for further investigations. (5, 6)  In summary, maintaining HDL levels between 40 mg/dl and 80 mg/dl is crucial for reducing the risk of developing cardiovascular disease and mortality from all causes.

From: https://www.everydayhealth.com/high-cholesterol/can-you-improve-your-cholesterol-and-triglyceride-levels/

What can be done?

         In conclusion, people exhibiting low HDL levels may need to increase it, as HDL protects our body from heart diseases. Many recent articles and papers are now being published, guiding and urging people to boost their HDL levels and providing ways to achieve higher HDL levels. Adopting a healthy lifestyle, including regular exercise, a balanced diet, and avoiding smoking, are some of the most beneficial that can help boost HDL levels. However, it is crucial that people with high HDL levels, higher than 80 mg/dl, should seek ways to reduce it. Changing the patient’s medication may be beneficial if the patient uses a statin or another prescription that boosts HDL levels. It is also essential to consult a doctor or a healthcare professional if there are any concerns about HDL or cholesterol levels. By focusing on maintaining overall health and well-being through healthy habits and regular check-ups, we can do our best to maintain a healthy cholesterol profile and reduce the risk of heart disease and other health problems. (7).

By Mahdi Barakat, A Master's of Medical Science Student at the University of Kentucky 

References:

1.           Rondanelli M, Giacosa A, Morazzoni P, Guido D, Grassi M, Morandi G, et al. MediterrAsian Diet Products That Could Raise HDL-Cholesterol: A Systematic Review. Biomed Res Int. 2016;2016:2025687.

            2.           Medicine NLo. Cholesterol December 10, 2020 [Available from: https://medlineplus.gov/cholesterol.html#cat_51.

            3.           Liu C, Dhindsa D, Almuwaqqat Z, Sun YV, Quyyumi AA. Very High High-Density Lipoprotein Cholesterol Levels and Cardiovascular Mortality. The American Journal of Cardiology. 2022;167:43-53.

            4.           Trimarco V, Izzo R, Morisco C, Mone P, Virginia Manzi M, Falco A, et al. High HDL (High-Density Lipoprotein) Cholesterol Increases Cardiovascular Risk in Hypertensive Patients. Hypertension. 2022;79(10):2355-63.

            5.           Hussain SM, Ebeling PR, Barker AL, Beilin LJ, Tonkin AM, McNeil JJ. Association of Plasma High-Density Lipoprotein Cholesterol Level With Risk of Fractures in Healthy Older Adults. JAMA Cardiology. 2023;8(3):268-72.

            6.           Kjeldsen EW, Nordestgaard LT, Frikke-Schmidt R. HDL Cholesterol and Non-Cardiovascular Disease: A Narrative Review. Int J Mol Sci. 2021;22(9).

            7.           Clinic M. HDL cholesterol: How to boost your 'good' cholesterol Nov 3, 2022 [Available from: https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/hdl-cholesterol/art-20046388.