What Causes High Cholesterol? And Why It Matters

Cholesterol is a waxy substance your body needs to make things like new cells, hormones, digestive fluids, and even vitamin D. When most people hear “cholesterol,” they think of heart disease. But there are different types of cholesterol — and not all are bad. 

The one that gets the most attention is low-density lipoprotein (LDL), or “bad” cholesterol. Too much LDL cholesterol in your blood can cause plaque to build up in your arteries (atherosclerosis). Over time, this can cause blockages. Blocked arteries may lead to things like heart attack, stroke, peripheral artery disease, and other serious health problems. 

Keep reading to learn about LDL cholesterol — what causes it to go up and why it’s bad for you. We’ll also explain high-density lipoprotein (HDL), or “good” cholesterol, and why your body needs it.

What causes high cholesterol?

More than 1 in 3 people in the U.S. have high cholesterol (hypercholesterolemia). There are many reasons you may have high cholesterol. Some people inherit it, but that only happens in 1 in 250 people.

Here are some of the more common causes of high cholesterol:

• Diet: This goes beyond the cholesterol content in your food. Certain types of fat and carbohydrates are more likely to raise your cholesterol. We’ll explain more about this next.

• Increased body fat: Fat in your abdominal area is more strongly linked to high cholesterol than overall body fat or weight.

• Tobacco use: This includes smoking and smokeless tobacco products.

• Lack of exercise: Getting at least 2 ½ hours of moderate- to high-intensity exercise each week may lower your LDL level and raise your HDL level. 

• Low thyroid hormone: When you treat low thyroid levels, your LDL cholesterol may improve.

• Low testosterone in men: Low testosterone is sometimes linked to higher LDL. But testosterone therapy doesn’t always reduce cholesterol.

• Menopause: Often, LDL cholesterol starts to rise about 5 years before menopause.

• Diabetes: Diabetes tends to raise LDL and triglycerides and lower HDL. People with prediabetes are also at risk.

• Some medications: Common offenders include beta blockers and diuretics. Long-term use of steroids like cortisone and some mental health medications are other examples.

• Polycystic ovary syndrome (PCOS): This common condition raises your risk for heart disease. So if you have PCOS, it’s important to monitor your LDL levels.

• Age over 40: Cholesterol numbers tend to go up with age, starting as early as your 40s.

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• Natural ways to lower your cholesterol: If you have high cholesterol, you may be able to lower it without medication. These lifestyle changes can make a big difference.

• Can red yeast rice lower cholesterol? Yes, but it works a lot like a statin medication. Read this before you try it.

• The best foods for lower cholesterol: From fatty fish to dark chocolate, there’s a wide range of foods that can help to lower your cholesterol.

What foods cause high cholesterol?

You can have high cholesterol even if you eat a low-cholesterol diet. That’s because your body makes its own cholesterol from many different parts of the foods you eat. For example, certain fats and processed carbohydrates affect your cholesterol levels.

Limiting these common foods may help to keep your cholesterol levels down:

• Red meat: This includes beef and pork, which are full of saturated fat. Saturated fat raises LDL cholesterol. Fattier cuts of meat have more saturated fat. But even lean meats can raise your heart disease risk compared to a plant-based diet.

• Poultry: Many people assume that eating poultry is better for cholesterol, but that’s not always true. One study found similar cholesterol levels in people who ate poultry versus red meat.

• Trans fats: These are banned in the U.S. because they’re harmful to the heart and other organs. But small amounts can still show up in foods made with certain oils. Very small amounts of trans fats also occur naturally in beef and dairy products. 

• Tropical oils: Palm oil and coconut oil are high in saturated fats and can raise LDL cholesterol. Processed and fried foods often contain these oils. Try using olive oil or nut oils instead. 

• Processed carbohydrates: This includes food made with white flour as well as many snack foods, like chips and cookies. They can affect your cholesterol level even when the foods are low in fat. 

• Egg yolks: One egg yolk contains about 200 mg of cholesterol. That’s the upper daily limit for people with heart disease or diabetes. Most people can enjoy an average of one whole egg daily without much effect on cholesterol. If you want to get the protein from eggs without the cholesterol, egg whites are a great option. 

• Dairy foods: These tend to be naturally higher in cholesterol and saturated fat. But research is mixed on how dairy affects cholesterol. Although butter raises LDL cholesterol, cheese doesn’t seem to. Studies haven’t found a link between high-fat dairy and heart disease. 

You may also be wondering about seafood. Shellfish are often said to be high in cholesterol. But research shows they don’t raise cholesterol levels. Just be careful with fried seafood — the frying oil can still be harmful.

Is high cholesterol always bad?

When we talk about cholesterol levels, the total number can be misleading. That’s because there’s more than one type of cholesterol:

• LDL is the “bad” kind. It’s most strongly connected to cholesterol plaque buildup.

• HDL cholesterol is considered the “good” kind. In general, people with HDL levels over 55 are less likely to die from heart disease than those with HDL under 35. 

• Very-low-density lipoprotein (VLDL) cholesterol is another type of cholesterol that carries triglycerides. Triglycerides are a type of fat that circulates in your blood. Lowering your triglycerides usually lowers your VLDL, too. 

Since your total cholesterol includes LDL, HDL, and VLDL, let’s look at two examples to help explain what the number really means:

1. Person A has a normal total cholesterol level. But they have low HDL (good) cholesterol and a higher LDL (bad) cholesterol.

2. Person B has a high total cholesterol level. But they have high HDL and low LDL cholesterol.

Person A is at much higher risk for things like heart disease, even though their total cholesterol is “normal.” Person B is at a lower risk, even though their total cholesterol is “high.”

It’s also helpful to remember that not everyone with high LDL will develop blockages in the heart or other organs. You have to look at the whole picture. For example, if you’re young and don’t have other risk factors, your high LDL may not be as dangerous right now. But if you’re over 60 or have other risk factors for heart disease, high LDL can be more serious. 

Finding high LDL early gives you a chance to lower it through lifestyle changes before medication is needed. But if your numbers stay high, they can lead to problems later in life.

What is a healthy cholesterol level?

When we talk about cholesterol, we usually focus on LDL. As we discussed earlier, your total cholesterol can be misleading. That’s why it’s important to look at all the numbers in your panel.

The healthiest cholesterol range for you depends on your unique situation and other medical conditions. For example:

• If you don’t have heart disease, the ideal LDL cholesterol is under 100 mg/dL. 

• If you do have heart disease, diabetes, or are at high risk for high cholesterol, it’s best to keep your LDL below 70 mg/dL. Some people may even benefit from an LDL under 55 mg/dL. Reaching these levels will likely need medication.

• Even if you have no risk factors, you may need treatment if your LDL cholesterol is over 160 mg/dL. That’s because numbers in this high range mean you’re more likely to develop problems early in life. If your number falls in this range, your high cholesterol may be due to your genes.

The average LDL in the U.S. is 120 mg/dL, so these ideal ranges might seem low. But in healthy, active people who don’t follow a typical Western diet or lifestyle, a normal LDL is usually between 50 mg/dL and 70 mg/dL. 

Dangers of high cholesterol

The higher your LDL, the more likely you are to develop atherosclerosis. This is a condition where fatty plaque builds up inside your arteries. 

Cholesterol plaque can narrow or block blood flow through your arteries. Arteries carry blood, oxygen, and nutrients to your organs and muscles. If you have cholesterol plaque, you’re at higher risk for the following problems: 

• Coronary artery disease, including heart attack and heart failure

• Stroke and TIA (transient ischemic attack)

• Peripheral artery disease, which can lead to amputation

• Aortic aneurysm, which can be deadly if not caught early

• Renal artery stenosis, which can cause kidney failure and high blood pressure

This list sounds scary, but the good news is that many of these problems can be prevented.

High cholesterol doesn’t usually cause symptoms until a problem develops. Some people with genetically high cholesterol may develop xanthoma — yellowish nodules on the face or other skin structures. But this is uncommon.

High cholesterol doesn’t cause dizziness, breathing problems, or even chest pain — unless there’s already a blockage. That’s why the first step is knowing your cholesterol numbers. If you’re a healthy adult with no major health issues, get a blood test every 5 years. If you have health conditions or risks, you may need more frequent testing.

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Written by:

Sarah A. Samaan, MD

Sarah Samaan, MD, FACC, FACP, FASE is a board-certified cardiologist who practiced clinical cardiology for nearly 30 years. She is a member of the American College of Cardiology, the American College of Physicians, and the American Society of Echocardiography.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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