HDL (good) and LDL (bad) cholesterol: How to diagnose? What are the symptoms, causes, and risk factors? What is a lipid profile test?
Although we know this, many of us are trying to manage our cholesterol. So what should we pay attention to in this management trend? Does cholesterol only occur in overweight people? Is the perception that people who are called thin based on their weight and height ratio do not have cholesterol a common misconception?
What is cholesterol? What functions does it have in our body?
Cholesterol is a waxy, fat-like substance that your body needs in the right amounts to be healthy. It takes part in the structure of the cell membrane, the formation of bile acids and is used in the synthesis of steroid hormones (testosterone, estrogen, progesterone, cortisol, etc.).
What are good (HDL) and bad (LDL) cholesterol?
The cholesterol our body needs is carried in the bloodstream by molecules called lipoproteins. These molecules, called lipoproteins, are named according to the ratio of cholesterol, protein and free fatty acids they contain.
High-density lipoprotein, called HDL-Cholesterol, is known as “good” cholesterol, while low-density lipoprotein, called LDL-Cholesterol, is known as “bad” cholesterol. Cholesterol types are not limited to HDL and LDL. There are also lipoproteins of different densities such as IDL, VLDL, chylomicron.
In current diagnosis and treatment guidelines, all cholesterol types except HDL-Cholesterol are considered negative for cardiovascular diseases, that is, “bad”. The common feature of these so-called “bad” cholesterol types is that they contain a substance called “Apolipoprotein B”.
How to understand good and bad cholesterol?
Cholesterol is a type of fat that is essential for our body. There are two types of cholesterol: good cholesterol (HDL) and bad cholesterol (LDL). Good cholesterol helps to remove bad cholesterol from our blood vessels, which can help protect against heart disease. Bad cholesterol, on the other hand, can accumulate in our blood vessels and increase the risk of heart disease.[1]
The level of bad cholesterol in our blood can be measured through a blood test. A normal LDL cholesterol level is below 100 mg/dL. The level of good cholesterol in our blood can also be measured through a blood test. A normal HDL cholesterol level is above 60 mg/dL.[2]
To lower bad cholesterol levels, it is recommended to follow a healthy diet, exercise regularly, avoid smoking, and limit alcohol consumption.[3, 4]
Are nutrition and body weight important for cholesterol levels?
As the amount of saturated fat and trans fat in the daily diet increases, the LDL-Cholesterol level increases. It is known that especially trans fats cause a decrease in HDL-Cholesterol. Trans fats can be found in limited amounts (<5% of total fat) in dairy products and animal foods. However, fats that pose a high risk for cardiovascular health are industrial-derived trans fats such as margarine.
Consumption of foods rich in unsaturated fat has been shown to reduce LDL-C levels. Examples of unsaturated fats are olive oil, avocados, nuts such as almonds, hazelnuts and walnuts, and fish, especially those rich in omega-3 and omega-6.
Reduction in body weight also affects total cholesterol levels, but this effect may not be as large as expected. According to studies conducted on obese individuals, a decrease of approximately 8 mg/dL in LDL cholesterol level is expected with a weight loss of 10 kg.
Why is cholesterol important? What problems can high cholesterol cause?
The most important problem that cholesterol disorders can cause is “atherosclerosis”.[5] Atherosclerosis; It is defined as plaques formed in the inner layer of the arteries due to the accumulation of cholesterol and inflammatory substances and the stenosis that occurs within the vessel as a result.
Atherosclerosis; It can affect all the arteries in our body, including the heart, brain, kidneys, arms and legs. It may have different names depending on which arteries are affected. As we all know, life-threatening conditions such as heart attack and stroke occur due to atherosclerosis.
Diseases caused by atherosclerosis are the diseases that cause the most deaths all over the world.
The atherosclerotic process begins to develop many years before its clinical consequences appear and, unfortunately, can progress without showing symptoms. It can be seen even at an early age in people with genetic predisposition if risk factors are present. The main these risk factors are; smoking, cholesterol, diabetes, hypertension and obesity.
What is the risk of cholesterol? At what level should high cholesterol be treated?
Although measurement of cholesterol levels is absolutely necessary for diagnosis and treatment approach, it is not possible to talk about a single limit value. Once cholesterol levels are measured, the patient’s “total cardiovascular risk” must be calculated.
There are a number of formulas that use parameters such as age, gender, family history, smoking, diabetes, hypertension and obesity to calculate the total cardiovascular risk. By calculating the total cardiovascular risk with a formula appropriate to the patient, the physician can make decisions about issues such as the need for further examination, initiation of treatment and type of treatment.
According to scientific studies conducted on tens of thousands of patients, it has been shown that every 1 mmol/L (38.7mg/dl) decrease in LDL-Cholesterol in patients treated with statins reduces cardiovascular events (heart attack, stroke, death) by 22%.[6]
Do drugs used to treat cholesterol have side effects?
The most common side effects include muscle pain, headache, abdominal pain, constipation, nausea, and loss of appetite. It is extremely rare that they cause liver and kidney damage, which causes unfounded fear especially among the public.
The effectiveness of drugs with such rare side effects, that is, the rate of cardiovascular events they manage to prevent (heart attack, stroke, etc.), is very high. Patients benefit greatly when used when deemed necessary by the physician and in the correct dosage. They have a very important place in the prevention and treatment of cholesterol and the problems it causes.
Measuring HDL and LDL cholesterol levels: What is the lipid profile test?
A lipid profile test is a blood test that measures the levels of various lipids in your blood, including cholesterol and triglycerides. It is also known as a coronary risk panel or lipid panel. The test is used to assess the risk of cardiovascular disease by measuring the amount of cholesterol and triglycerides in your blood.[7]
A complete lipid profile test includes the measurement of the following:
- Total cholesterol: The total amount of cholesterol in your blood.
- Low-density lipoprotein (LDL) cholesterol: Also known as “bad” cholesterol, this type of cholesterol can build up in your arteries and increase your risk of heart disease.
- High-density lipoprotein (HDL) cholesterol: Also known as “good” cholesterol, this type of cholesterol helps remove LDL cholesterol from your blood vessels and can help protect against heart disease.
- Triglycerides: A type of fat found in your blood that can increase your risk of heart disease if levels are too high.
To prepare for a lipid profile test, you should not consume any food or beverages for at least 10 hours before the test. The procedure involves the withdrawal of a blood sample, which is usually drawn from a vein at the back of the hand or inside the elbow. The results of the test are usually available within 1-2 days.[8]
Normal results for a lipid profile test are as follows:
- Total cholesterol: Less than 200 mg/dL.
- LDL cholesterol: Less than 100 mg/dL (less than 70 mg/dL if you have diabetes or coronary artery disease).
- Non-HDL cholesterol: Less than 130 mg/dL.
- Fasting triglycerides: Less than 150 mg/dL.
Abnormal results and high lipids are inferred when:
- Total cholesterol: 240 mg/dL or higher.
- LDL cholesterol: Between 160-189 mg/dL.
- HDL cholesterol: Greater than 60 mg/dL.
- Non-HDL cholesterol: Between 190-219 mg/dL.
- Fasting triglycerides: Between 160-189 mg/dL.
It’s important to note that while a lipid profile test can help assess your risk of heart disease, it should not be used as a substitute for medical treatment or advice. If you have any concerns about your health, please consult a healthcare professional.
References:
- High cholesterol: Symptoms, Causes, Risk factors, Complications, and Prevention. CON-20155272, Mayo Clinic Staff. (Jan. 11, 2023)
- LDL and HDL Cholesterol and Triglycerides, CDC, Last Reviewed: May 16, 2023 Source: National Center for Chronic Disease Prevention and Health Promotion , Division for Heart Disease and Stroke.
- Why You Should No Longer Worry About Cholesterol in Food, Cleveland Clinic (January 14, 2021).
- HDL (Good), LDL (Bad) Cholesterol and Triglycerides, Written by American Heart Association editorial staff and reviewed by science and medicine advisors. Last Reviewed: Nov 6, 2020.
- What Is Atherosclerosis? NIH National Heartl, Lung, and Blood Institute, Last updated on March 24, 2022
- Antonio J. Vallejo-Vaz, Michele Robertson, Alberico L. Catapano, Gerald F. Watts, John J. Kastelein, Chris J. Packard, Ian Ford and Kausik K. Ray. Low-Density Lipoprotein Cholesterol Lowering for the Primary Prevention of Cardiovascular Disease Among Men With Primary Elevations of Low-Density Lipoprotein Cholesterol Levels of 190 mg/dL or Above. Circulation. 2017;136:1878–1891 (6 Sep 2017)
- What is a lipid profile? Medically reviewed by Drugs.com. Last updated on Dec 4, 2023.
- Cholesterol and lipid tests, Healthdirect Australia, Last reviewed: December 2022.