What Is Cholesterol and Why Does It Matter?
Cholesterol is a waxy, fat-like substance made by your liver that is essential for good health. While your body needs cholesterol to function properly, too much cholesterol puts you at risk for heart disease and stroke, two leading causes of death in the United States.
Cholesterol is a waxy, fat-like substance that your body needs for good health, but in the right amounts. It is an important component of the cell membrane, contributes to the structural makeup and fluidity of membranes, and functions as a precursor molecule in the synthesis of vitamin D, steroid hormones, and sex hormones.
Understanding the Different Types of Cholesterol
Not all cholesterol is created equal. When you get your cholesterol checked, you'll typically see several different measurements:
LDL Cholesterol: The "Bad" Cholesterol
High levels of low-density lipoprotein cholesterol (LDL-C) is a major risk factor for atherosclerotic cardiovascular disease (ASCVD) because LDL-C contributes to fatty buildups and narrowing of the arteries (atherosclerosis). Having high levels of LDL cholesterol can lead to plaque buildup in your arteries and result in heart disease or stroke.
HDL Cholesterol: The "Good" Cholesterol
HDL (high-density lipoprotein) or "good" cholesterol is known as beneficial because high levels of it can lower your risk of heart disease and stroke. HDL cholesterol carries cholesterol and plaque to the liver to be flushed out of the body.
Triglycerides
Triglycerides are a type of fat in your blood that your body uses for energy, and the combination of high levels of triglycerides with either low HDL cholesterol or high LDL cholesterol levels can increase your risk for heart attack and stroke.
What Are Normal Cholesterol Levels?
If you are an adult or child, a total cholesterol above 200 mg/dL may be considered high. High total cholesterol is 240 mg/dL or more.According to medical guidelines:
- Total Cholesterol: Less than 200 mg/dL is desirable
- LDL Cholesterol: Below 100 mg/dL is optimal for healthy people in the absence of coronary artery disease; if you have heart disease, your LDL should be below 70 mg/dL
- HDL Cholesterol: For females, it should be above 50 mg/dL; for males, it should be above 40 mg/dL
- Triglycerides: Less than 150 mg/dL is optimal
How High Cholesterol Leads to Heart Disease
Having high blood cholesterol can lead to a buildup called "plaque" on the walls of your arteries; as plaque builds up over time, the insides of your arteries narrow, blocking blood flow to and from your heart and other organs, which can cause chest pain (angina) or a heart attack.When you have too much LDL cholesterol in your blood, it can join with fats and other substances to build up in the inner walls of your arteries, creating plaque; the arteries can become clogged and narrow, and if the buildup of plaque ruptures, a blood clot may form causing a heart attack or stroke.
The Evidence: How Much Does Lowering Cholesterol Help?
The scientific evidence is overwhelming. Studies consistently demonstrate a 20%-22% relative risk reduction for each 1 mmol/L decrease in LDL-C blood levels. The LDL-C hypothesis holds that high blood LDL-C levels are a major risk factor for atherosclerosis cardiovascular disease (ASCVD) and lowering LDL-C levels will reduce the risk for ASCVD, based on epidemiological evidence and randomized clinical trials.
Statistics: The Scope of the Problem
The numbers reveal a significant public health challenge:
- Between 2017 and 2020, 10% of adults age 20 or older had total cholesterol levels above 240 mg/dL, and about 17% had HDL cholesterol levels below 40 mg/dL
- About 86 million US adults age 20 or older have total cholesterol levels above 200 mg/dL, and nearly 25 million adults have total cholesterol levels above 240 mg/dL
- Slightly more than half of US adults (54.5%, or 47 million people) who could benefit from cholesterol medicine are currently taking it
Who Is at Risk for High Cholesterol?
Certain health conditions, such as type 2 diabetes and obesity, can raise your risk for high cholesterol, as can lifestyle factors such as eating a diet high in saturated and trans fats and not getting enough activity; some people who have a family history of high cholesterol can also be at risk.
Additional risk factors include:
- Poor diet
- Physical inactivity
- Smoking
- Being overweight
- Age (risk increases as you get older)
- Family history of high cholesterol
How to Lower Your Cholesterol
Lifestyle Changes
High cholesterol can be lowered, reducing risk of heart disease and stroke; the best way to lower your cholesterol is to reduce your intake of saturated and trans fats.Key lifestyle modifications include:
1. Heart-Healthy Diet
- Reduce your intake of red meat and dairy products made with whole milk; choose skim milk, low-fat or fat-free dairy products; include fruits, vegetables, whole grains, poultry, fish and nuts, and limit sodium, sugar and fried foods
- A sedentary lifestyle lowers your good HDL cholesterol; aim for at least 150 minutes of physical activity per week
- Being overweight or obese can raise bad cholesterol and lower good cholesterol; losing as little as 5% to 10% of your body weight can improve cholesterol numbers
- Smoking and vaping lowers good HDL cholesterol
Medications
In primary and secondary prevention, when high cholesterol can't be controlled by diet or exercise, statins are typically used to lower LDL cholesterol levels and CVD risk; the guideline recommends a stepped approach that adds ezetimibe to statin therapy, and if that combination isn't successful, adding a PCSK9 inhibitor for patients at very high risk.
The New 2025 Guidelines
The 2025 American College of Cardiology/American Heart Association guidelines for acute coronary syndromes represent a meaningful evolution in lipid-lowering therapy, moving beyond the historical paradigm that focused on statins with LDL-C ≥70 mg/dL as the threshold for treatment intensification.
The new guidelines establish more stringent LDL-C targets, with therapy intensification considered reasonable if LDL-C falls between 55 and 69 mg/dL, particularly among patients with significant residual risk factors such as diabetes, polyvascular disease, or elevated lipoprotein(a).
Getting Your Cholesterol Checked
Most healthy adults should have their cholesterol checked every 4 to 6 years; some people, such as those who have heart disease, diabetes, or a family history of high cholesterol, need to get their cholesterol checked more often.
High cholesterol has no symptoms, so many people don't know that their cholesterol is too high; a simple blood test can check cholesterol levels.
Key Takeaways
Understanding your cholesterol levels is crucial for preventing heart disease. Here's what you need to remember: Get your cholesterol checked regularly starting at age 20 Know your numbers: total cholesterol, LDL, HDL, and triglycerides Lower is generally better for LDL cholesterol Lifestyle changes can significantly impact your cholesterol levels Work with your healthcare provider to create a personalized treatment plan If lifestyle changes aren't enough, medications like statins can help
In all individuals, emphasize a heart-healthy lifestyle across the life course; a healthy lifestyle reduces atherosclerotic cardiovascular disease (ASCVD) risk at all ages, and in younger individuals can reduce development of risk factors.
References
American Heart Association - Comprehensive information about cholesterol and heart health: https://www.heart.org/en/health-topics/cholesterol
Mayo Clinic - High cholesterol symptoms and causes: https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/symptoms-causes/syc-20350800
Centers for Disease Control and Prevention (CDC) - About cholesterol facts and statistics: https://www.cdc.gov/cholesterol/about/index.html
National Heart, Lung, and Blood Institute (NIH) - Blood cholesterol information: https://www.nhlbi.nih.gov/health/blood-cholesterol
National Center for Biotechnology Information (NCBI) - Guidelines for management of high blood cholesterol: https://www.ncbi.nlm.nih.gov/books/NBK305897/
This article is for informational purposes only and does not constitute medical advice. Always consult with your healthcare provider about your cholesterol levels and treatment options.