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Cholesterol is a waxy, fat-like substance that’s found throughout your body. It often gets a bad reputation, but you actually need a certain amount of cholesterol to make substances that are essential for good health, such as:

  • bile acids, which help you absorb fat-soluble vitamins
  • hormones, like estrogen and androgen
  • cell membranes

However, cholesterol levels that are too high can increase the risk of several chronic conditions, including a stroke.

Read on to learn how high cholesterol can cause a stroke, plus ways to reduce your blood cholesterol if needed.

The cholesterol in your blood is made by your liver. Your lifestyle and the foods you eat can affect your cholesterol levels.

Cholesterol is unable to travel through your blood on its own. Your liver makes lipoproteins, or particles that transport cholesterol in your arteries.

There are different types of cholesterol:

  • LDL cholesterol. Low-density lipoprotein (LDL) cholesterol, or “bad“ cholesterol, transports cholesterol from the liver to other cells. This unhealthy type of cholesterol can contribute to the buildup of plaque, which can narrow and clog your arteries.
  • HDL cholesterol. High-density lipoprotein (HDL) cholesterol is known as “good” cholesterol. This healthy type of cholesterol helps clear LDL cholesterol from your arteries, which reduces your risk of stroke. Unlike LDL cholesterol, you want to have higher levels of HDL cholesterol in your blood.
  • Triglycerides. Triglycerides are a type of fat that’s found in your blood. Your body converts extra calories into triglycerides, which are stored in your fat cells. If you tend to eat more calories than you burn, you may have high triglycerides — a condition known as hypertriglyceridemia. Having high triglyceride levels plus high LDL or low HDL increases the risk of plaque buildup in your arteries.
  • Total cholesterol. Total cholesterol is the sum of your LDL and HDL cholesterol levels, along with 20 percent of your triglyceride levels.

You need a fasting blood test to know what your blood cholesterol levels are. The test is called a lipid profile, or lipid panel.

The results will be listed as milligrams per deciliter (mg/dL). The following chart explains how the results are categorized:

LDL CholesterolHDL CholesterolTriglyceridesTotal Cholesterol
DesirableLess than 100 mg/dL40 mg/dL or higher for males and 50 mg/dL or higher for females is acceptable; 60 mg/dL or higher is desirable
(the higher the number the better)
Less than 149 mg/dL; the ideal level is below 100 mg/dLLess than 200 mg/dL
Borderline/ moderately elevated 130–159 mg/dLn/a150–199 mg/dL200–239 mg/dL
High160 mg/dL (190 and higher is very high)n/a200–499 mg/dL (500 and above is very high)240 mg/dL or higher
Lown/aLess than 40 mg/dL for males and less than 50 mg/dL for females n/an/a

A stroke occurs when your brain is unable to get sufficient blood in order to function properly. When this happens, the brain cells may begin to die.

There are two main types of strokes:

  • Ischemic stroke. With an ischemic stroke, a blood vessel is blocked by a blood clot or plaque.
  • Hemorrhagic stroke. A hemorrhagic stroke happens when a blood vessel ruptures, causing sudden bleeding.

High blood cholesterol levels can specifically increase your risk of an ischemic stroke. That’s because high cholesterol contributes to plaque buildup in the arteries, a condition called atherosclerosis. Plaque is a fatty substance that’s made of:

  • cholesterol
  • cellular waste products
  • fibrin
  • calcium

Plaque buildup can make your arteries narrower and stiffer. In turn, this can restrict blood flow in your arteries, including the arteries in your brain. If an artery becomes blocked, cutting off blood flow in parts of your brain, it can cause an ischemic stroke.

There are several causes of high cholesterol levels. Some causes are inherited, or present at birth, while others may develop later in life.

Causes can include:

  • Familial hypercholesterolemia. Familial hypercholesterolemia is a genetic disorder in which your body is unable to properly remove LDL cholesterol from your blood. This causes high levels of LDL cholesterol.
  • Consuming too much high fat food. Eating too much saturated fat and trans fats can lead to higher levels of LDL cholesterol.
  • Consuming more calories than you need. When you eat more calories than you can burn, your body converts the extra calories into triglycerides, which can lead to more plaque buildup in your arteries.
  • Having overweight or obesity. A review of 25 studies found that obesity increased the risk of ischemic stroke by 64 percent.
  • Lack of exercise. Not getting enough physical activity can lead to higher triglycerides, higher cholesterol levels, and an increased risk of stroke.
  • Smoking cigarettes. Smoking cigarettes increases LDL cholesterol and triglyceride levels. It also decreases HDL cholesterol.
  • Diabetes. According to 2017 research, people with diabetes are more than twice as likely to have an ischemic stroke compared with people who don’t have diabetes.
  • Older age. Over time, it becomes harder for the body to remove cholesterol from the blood. This can lead to higher cholesterol levels.

In addition to high cholesterol, other factors may increase your risk of an ischemic stroke, such as:

The leading risk factors for a hemorrhagic stroke include:

It’s possible to lower your cholesterol with lifestyle changes and medications.

Tips for lowering your cholesterol

  • Eat a nutritious, balanced diet. Avoid or limit foods high in saturated and trans fats, like fried foods, red meat, and processed foods. Aim to eat more fruits, vegetables, whole grains, and lean meats.
  • Focus on soluble fiber. Soluble fiber may help reduce your total and LDL cholesterol levels. Foods high in soluble fiber include whole grains, beans, and vegetables like broccoli and carrots.
  • Stay active. Aim for 150 minutes of physical activity a week. If you’re new to exercise, or if you have mobility issues, ask your doctor for suggestions on how to stay active in a safe way.
  • Consider quitting smoking. If you smoke cigarettes, quitting can help improve your cholesterol levels and overall health.
  • Take cholesterol-lowering medications. Your doctor can prescribe medication to help manage your cholesterol levels. This may include drugs like statins, bile acid sequestrants, or cholesterol absorption inhibitors.

Once your cholesterol levels are within a normal range, it’s important to continue following a health-promoting lifestyle in order to keep your cholesterol levels within a normal range.

High cholesterol contributes to the formation of plaque that can build up in your arteries and block blood flow to your brain, causing a stroke.

In some cases, high cholesterol may be due to familial hypercholesterolemia, a genetic disorder. Other factors that can affect your cholesterol levels include:

  • diet
  • exercise
  • tobacco use
  • high blood pressure
  • type 2 diabetes
  • older age

Since high cholesterol causes no symptoms, the best way to check your levels is to get a blood test. If your cholesterol levels are high, your doctor may suggest lifestyle changes or cholesterol-lowering medications.