Cholesterol: Key Facts, Levels and Health Risks

Jun 26, 2024 | 8 min read

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Cholesterol is a crucial biomarker for cardiovascular health. High levels can lead to serious diseases, making it essential to manage cholesterol through diet, exercise, and regular testing.

What is Cholesterol?

Cholesterol is a waxy, fat-like substance found in every cell of your body. It's essential for various bodily functions, including building cell membranes, producing hormones, and making vitamin D. Cholesterol travels through your bloodstream in small packages called lipoproteins, which are combinations of fat (lipid) and protein.

While cholesterol is vital for your health, having too much of it can lead to serious health problems.

There are two main sources of cholesterol in your body:

  • Endogenous Cholesterol: This type of cholesterol is produced by your liver. Your liver makes all the cholesterol your body needs to function properly. The liver regulates cholesterol levels, ensuring you have enough for your body's needs without overproducing it.
  • Exogenous Cholesterol: This cholesterol comes from your diet, specifically from animal-based foods like meat, poultry, and dairy products. These foods contain dietary cholesterol, which can add to the cholesterol produced by your liver. Foods high in saturated and trans fats can increase your cholesterol levels, especially LDL, the "bad" cholesterol.

Understanding the balance between these two sources is crucial for managing your cholesterol levels and maintaining heart health. By knowing where cholesterol comes from and how it works in your body, you can make informed choices about your diet and lifestyle.


According to the CDC:

  • Approximately 7% of children and adolescents in the United States, aged 6 to 19, have high total cholesterol.
  • Around 86 million US adults aged 20 and older have total cholesterol levels above 200 mg/dL.
  • Nearly 25 million adults in the United States have total cholesterol levels exceeding 240 mg/dL.
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Types of Cholesterol

Cholesterol is carried through your bloodstream by lipoproteins. The two main types of cholesterol-carrying lipoproteins are low-density lipoprotein (LDL) and high-density lipoprotein (HDL). There is also a less commonly discussed type called very low-density lipoprotein (VLDL).

Low-Density Lipoprotein (LDL)

LDL is often referred to as "bad" cholesterol. This is because high levels of LDL cholesterol can lead to plaque buildup in your arteries. Plaque is a thick, hard deposit that can clog arteries and make them less flexible, a condition known as atherosclerosis. When plaque builds up, it can lead to serious health problems, such as heart attacks or strokes.

LDL cholesterol contributes to plaque buildup by depositing cholesterol directly into the walls of your arteries. Over time, this buildup narrows the arteries, restricting blood flow and increasing the risk of cardiovascular events. Managing LDL levels is crucial for reducing the risk of heart disease.

Very Low-Density Lipoprotein (VLDL)

VLDL is another type of "bad" cholesterol. It primarily carries triglycerides, which are fats, in the blood. Like LDL, high levels of VLDL can contribute to the buildup of plaque in the arteries. Triglycerides are necessary for energy, but having too many in your blood can increase the risk of atherosclerosis.

Managing VLDL levels is important because high VLDL can indicate an increased risk of heart disease. VLDL can be reduced through a healthy diet, regular exercise, and lifestyle changes, similar to the strategies used to manage LDL cholesterol.

High-Density Lipoprotein (HDL)

HDL is known as "good" cholesterol because it helps remove excess cholesterol from your bloodstream. HDL carries cholesterol away from the arteries and back to the liver, where it can be processed and removed from the body. This helps prevent the buildup of cholesterol in the arteries, reducing the risk of heart disease and stroke.

Having higher levels of HDL cholesterol is beneficial because it can offset the harmful effects of LDL cholesterol. Think of HDL as the cleanup crew for your arteries, ensuring that excess cholesterol doesn't lead to dangerous plaque formation.

Why Cholesterol Levels Matter

The Relationship Between Cholesterol Levels and Heart Disease Risk

Cholesterol levels are a crucial factor in determining your risk for heart disease. High levels of LDL cholesterol and triglycerides, combined with low levels of HDL cholesterol, can lead to the development of atherosclerosis. This is a condition where plaque builds up in the arteries, narrowing them and making it harder for blood to flow through.

How High Cholesterol Leads to Plaque Buildup and Atherosclerosis

When you have high cholesterol, especially high LDL levels, cholesterol particles can start to deposit in the walls of your arteries. Over time, these deposits form plaques. Plaque buildup, or atherosclerosis, can restrict blood flow to vital organs, including the heart and brain.

This plaque can also become unstable and rupture, leading to the formation of blood clots. These clots can block blood flow completely, causing serious health issues like heart attacks and strokes.

Potential Consequences of High Cholesterol

High cholesterol can lead to several serious health problems, including:

  • Coronary Artery Disease: Plaque buildup in the arteries that supply blood to the heart can cause chest pain (angina) and heart attacks.
  • Peripheral Artery Disease: This occurs when plaque builds up in the arteries that supply blood to the legs and arms, leading to pain and mobility issues.
  • Carotid Artery Disease: Plaque buildup in the arteries that supply blood to the brain can cause strokes or transient ischemic attacks (mini-strokes).

Managing your cholesterol levels is crucial for reducing the risk of these conditions. Regular testing, a healthy lifestyle, and working with your healthcare provider can help you maintain healthy cholesterol levels and protect your heart health.

How to Measure Cholesterol

Lipid Panel Test

To determine your cholesterol levels, healthcare providers use a blood test called a lipid panel or lipid profile. This test measures the amount of different types of cholesterol and fats in your blood.

The lipid panel provides the following key measurements:

  • Total Cholesterol: The overall amount of cholesterol in your blood.
  • LDL Cholesterol: The "bad" cholesterol that can lead to plaque buildup in arteries.
  • HDL Cholesterol: The "good" cholesterol that helps remove excess cholesterol from your blood.
  • Triglycerides: A type of fat in the blood that can increase the risk of heart disease if levels are too high.

Preparation for a Cholesterol Test

Proper preparation for a cholesterol test is essential for accurate results. Here are some important steps to follow:

  • Fasting: Most lipid panel tests require fasting for 9-12 hours before the test. This means you should avoid eating or drinking anything except water during this period. Fasting ensures that food and drink do not affect your cholesterol and triglyceride levels.
  • Medications: Inform your healthcare provider about any medications, supplements, or vitamins you are taking, as some can affect cholesterol levels.
  • Hydration: Drink plenty of water before the test to stay hydrated, as dehydration can affect blood test results.
  • Avoid Alcohol: Refrain from consuming alcohol for at least 24 hours before the test, as it can influence triglyceride levels.

Cholesterol Levels by Age and Sex

Note: Test results can differ based on factors such as your age, gender, health history, the testing method, and other variables. Your results may not necessarily indicate a problem. Consult with your healthcare provider to understand what your specific test results mean for you.

Cholesterol Levels for Adults (20 and Older):

Cholesterol Normal Ranges according to the Johns Hopkins Medicine

Cholesterol Type Optimal Range Borderline High High
Total Cholesterol 125-200 mg/dL 200-239 mg/dL 240 mg/dL or higher
LDL Cholesterol <100 mg/dL 100-159 mg/dL 160 mg/dL or higher
HDL Cholesterol >40 mg/dL for men 
>50 mg/dL for women
40-59 mg/dL for men
50-59 mg/dL for women
<40 mg/dL for men 
<50 mg/dL for women
Triglycerides <150 mg/dL 150-199 mg/dL 200 mg/dL or higher

Cholesterol Levels for Children and Teens (19 and Younger):

Recommendations from the University of Rochester Medical Center:

Cholesterol Type Optimal Range Borderline High High
Total Cholesterol <170 mg/dL 170-199 mg/dL 200 mg/dL or higher
LDL Cholesterol <110 mg/dL 110-129 mg/dL 130 mg/dL or higher
HDL Cholesterol >45 mg/dL - <45 mg/dL
Triglycerides < 75 mg/dL (ages 0-9) 
<90 mg/dL (ages 10-19)
75-99 mg/dL (ages 0-9)
90-129 mg/dL (ages 10-19)
100 mg/dL or higher (ages 0-9) 
130 mg/dL or higher (ages 10-19)

Understanding the Test Results and Their Implications

After the lipid panel test, you will receive your cholesterol numbers. Here's what they mean:

High levels of cholesterol generally indicate an increased risk of cardiovascular diseases, including heart disease, stroke, and peripheral artery disease. Elevated LDL cholesterol and triglycerides, along with low HDL cholesterol, are key indicators of these conditions.

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When to Check Your Cholesterol?

The American Heart Association recommends that:

  • Before 20: The first test should be between ages 9 to 11
  • Routine Screening for Adults 20 or Older: All adults aged 20 or older have their cholesterol and other traditional risk factors checked every four to six years, as long as their risk remains low.
  • Increased Monitoring After Age 40: After the age of 40, your healthcare professional will use an equation to calculate your 10-year risk of having a heart attack or stroke, which may require more frequent cholesterol checks.
  • High-Risk Individuals: People with cardiovascular disease or those at elevated risk should have their cholesterol and other risk factors assessed more often, as advised by their healthcare provider.
  • Personalized Health Advice: Your healthcare professional will explain what your cholesterol levels mean, discuss treatment options if necessary, and provide guidance tailored to your health needs.

Risk Factors for High Cholesterol

Dietary Factors Influencing Cholesterol Levels

Foods That Raise LDL Cholesterol:

  • Saturated Fats: Found in red meat, full-fat dairy products, butter, and certain oils like coconut and palm oil.
  • Trans Fats: Present in many processed and fried foods, as well as baked goods made with partially hydrogenated oils.
  • Cholesterol-Rich Foods: Found in high amounts in organ meats, shellfish, and full-fat dairy products.

Foods That Help Lower Cholesterol:

  • Soluble Fiber: Found in oats, fruits, vegetables, and legumes. It helps reduce the absorption of cholesterol in the bloodstream.
  • Healthy Fats: Found in nuts, seeds, avocados, and olive oil. These can help increase HDL cholesterol and reduce LDL cholesterol.
  • Omega-3 Fatty Acids: Found in fatty fish like salmon, mackerel, and sardines. They help lower triglycerides and may improve heart health.
  • Whole Grains: Oats, barley, and whole wheat are good sources of soluble fiber.
  • Lean Proteins: Choose lean meats, fish, and plant-based proteins like beans and lentils

Lifestyle Factors Affecting Cholesterol

  • Exercise: Regular physical activity helps increase HDL cholesterol and lower LDL cholesterol and triglycerides. Aim for at least 30 minutes of moderate exercise most days of the week.
  • Smoking: Smoking lowers HDL cholesterol and damages the walls of blood vessels, making it easier for LDL cholesterol to accumulate. Quitting smoking improves HDL levels and overall heart health.
  • Alcohol Consumption: Drinking alcohol in moderation can have a positive effect on HDL cholesterol, but excessive drinking increases the risk of high triglycerides and other health issues. Stick to recommended guidelines for alcohol consumption.

Genetic Factors and Family History

Genetics play a significant role in determining your cholesterol levels. If high cholesterol runs in your family, you may be at a higher risk, regardless of lifestyle choices. Familial hypercholesterolemia is a genetic condition that results in very high LDL cholesterol levels from a young age. If you have a family history of high cholesterol or heart disease, it's essential to monitor your cholesterol levels regularly and take preventive measures.

Medical Conditions Leading to High Cholesterol

Certain medical conditions can also contribute to high cholesterol levels. These include:

  • Diabetes: High blood sugar levels can lead to higher LDL cholesterol and lower HDL cholesterol, increasing the risk of atherosclerosis.
  • Hypothyroidism: An underactive thyroid can cause an increase in total cholesterol and LDL cholesterol levels.
  • Kidney Disease: Chronic kidney disease can lead to higher levels of LDL cholesterol and triglycerides.
  • Liver Disease: Since the liver plays a crucial role in processing cholesterol, liver disease can disrupt cholesterol levels.

Managing these conditions through proper medical care and lifestyle adjustments is vital for controlling cholesterol levels and reducing the risk of heart disease.

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