Cholesterol And Strokes: What's The Connection?

High cholesterol is a common condition, affecting more than one in five adults in the UK. It is a fatty substance called a lipid, which is found in the blood. While cholesterol is important for our digestive and hormonal systems, high levels can be harmful. Excess cholesterol can enter the bloodstream and cause a build-up of fatty deposits in the arteries, which can become narrow and stiff. This process, called atherosclerosis, can lead to a clot forming and travelling to the brain, causing a stroke. However, the relationship between cholesterol and stroke is complex, and it varies depending on the type of stroke and the type of cholesterol involved.

High cholesterol is linked to stroke risk

Cholesterol is a waxy, fatty substance called a lipid that is found in the blood. It is produced by the liver and is essential to the body's digestive and hormonal systems. However, high levels of cholesterol can be harmful. More than one in five adults in the UK have high cholesterol.

There are two types of cholesterol: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL is known as 'bad cholesterol' because it can build up on artery walls, causing problems with the circulatory system. HDL, on the other hand, is known as 'good cholesterol' because it helps to carry LDL away from blood cells and back to the liver, where it can be processed and removed from the body.

High levels of LDL cholesterol are linked to an increased risk of ischemic stroke, the most common type of stroke caused by a blockage of blood flow. Levels of LDL cholesterol higher than 130 milligrams per deciliter (mg/dL) are associated with a higher risk of ischemic stroke. In contrast, HDL levels higher than 35 mg/dL offer protection against ischemic stroke.

While high cholesterol is a risk factor for stroke, it is important to note that other factors also contribute to stroke risk. These include being overweight or obese, smoking, alcohol consumption, a poor diet, a sedentary lifestyle, and a family history of stroke.

The two types of cholesterol

High cholesterol can lead to heart disease and strokes. While the body needs some cholesterol to keep cells and organs healthy, too much LDL cholesterol in the blood increases the risk of coronary artery disease and other heart diseases.

There are two types of cholesterol: low-density lipoprotein (LDL), or "bad" cholesterol, and high-density lipoprotein (HDL), or "good" cholesterol.

LDL cholesterol contributes to fatty buildups in arteries (atherosclerosis). This narrows the arteries and increases the risk of heart attack, stroke, and peripheral artery disease. Lifestyle factors are the main determinant of cholesterol levels. A diet high in red meat, full-fat dairy products, saturated fats, trans fats, and processed foods can lead to higher LDL levels.

HDL cholesterol, on the other hand, helps to protect against heart attack and stroke by carrying LDL cholesterol away from the arteries and back to the liver, where it is broken down and passed from the body. Optimal levels of HDL can protect the body from the negative effects of LDL.

While it is important to maintain healthy levels of both types of cholesterol, having high HDL levels is not enough to compensate for high LDL levels. Lowering LDL levels through lifestyle changes, such as improving diet and increasing physical activity, is crucial for reducing the risk of cardiovascular disease.

The two types of stroke

While high cholesterol is a risk factor for ischemic strokes, it is important to understand the two main types of stroke: ischemic and hemorrhagic.

Ischemic Stroke

An ischemic stroke occurs when a blood vessel supplying blood to the brain is blocked by a blood clot. This is the most common type of stroke, accounting for 87% of all strokes. Atherosclerosis, a process where fatty plaque builds up in the arteries and slows blood flow, is a common cause of ischemic strokes. There are two main types of ischemic stroke:

• Thrombotic strokes: Caused by a blood clot that forms in an artery supplying blood to the brain.
• Embolic strokes: Occur when a clot forms elsewhere in the body and travels to the brain, blocking blood flow.

Hemorrhagic Stroke

A hemorrhagic stroke happens when a weakened blood vessel ruptures and bleeds into the brain. This type of stroke is less common but can be very serious. The two types of weakened blood vessels that usually cause hemorrhagic strokes are aneurysms and arteriovenous malformations (AVMs). Uncontrolled high blood pressure is the most common cause of hemorrhagic strokes. There are two subtypes of hemorrhagic stroke:

• Subarachnoid hemorrhage: Bleeding occurs in the area between the brain and the skull.
• Intracerebral hemorrhage: Bleeding occurs inside the brain.

How to lower cholesterol

While there is no direct relation between high cholesterol and strokes, it is still important to maintain healthy cholesterol levels to lower the risk of heart disease. Cholesterol is a waxy, fat-like substance found in all the cells in your body. Your body needs some cholesterol to function properly, but too much can stick to the walls of your arteries, narrowing or blocking them, which can lead to coronary artery disease and other heart diseases.

Lifestyle Changes

• Heart-healthy eating: Limit your consumption of saturated and trans fats. Consume only enough calories to maintain a healthy weight and avoid weight gain. Choose a variety of nutritious foods, including fruits, vegetables, whole grains, and lean meats. The Therapeutic Lifestyle Changes diet and the DASH eating plan are examples of eating plans that can help lower cholesterol.
• Achieve and maintain a healthy weight: If you are overweight or obese, losing weight can help lower your LDL (bad) cholesterol and raise your HDL (good) cholesterol. This is especially important for individuals with metabolic syndrome, a group of conditions that increase the risk of heart diseases and other health problems.
• Increase physical activity: Physical activity has been shown to lower LDL cholesterol and triglycerides while raising HDL cholesterol. Consult with your healthcare provider to determine the appropriate level of physical activity for you.
• Manage stress: Chronic stress has been linked to increased LDL cholesterol and decreased HDL cholesterol.
• Quit smoking: Quitting smoking can raise HDL cholesterol, which helps to remove LDL cholesterol from your arteries, thereby lowering overall LDL levels.
• Get adequate sleep: Aim for 7 to 9 hours of sleep every night to lower your risk of high LDL and total cholesterol levels.

Medicines and Supplements

• For some individuals, lifestyle changes alone may not be sufficient to lower cholesterol to healthy levels. In these cases, cholesterol-lowering medications may be recommended. Consult with your healthcare provider to determine the most appropriate medication for you.
• Plant stanols and sterols supplements, when taken with meals, can help reduce cholesterol levels.
• Some soy products and whole flaxseed or flaxseed lignans may have a modest cholesterol-lowering effect, although eating soy foods is generally more beneficial than taking supplements.
• Garlic supplements may also lower cholesterol levels, but the effect is relatively small compared to cholesterol medications.

How to test for high cholesterol

While there is no direct relation between high cholesterol and strokes, high levels of LDL cholesterol can lead to plaque buildup in your arteries, which can result in a stroke. Therefore, it is important to get your cholesterol checked regularly.

A cholesterol test is a simple blood test that measures the amount of cholesterol and certain fats in your blood. It is also known as a "lipid profile" or "lipid panel". The test checks your levels of:

• Low-density lipoprotein (LDL) or "bad" cholesterol. High levels of LDL cholesterol can lead to plaque buildup in your arteries, increasing your risk for coronary artery disease and other heart diseases, including stroke.
• High-density lipoprotein (HDL) or "good" cholesterol. HDL helps to get rid of "bad" LDL cholesterol, lowering your risk of heart disease and stroke.
• Triglycerides, a type of fat in your blood. High levels of triglycerides, combined with low HDL cholesterol or high LDL cholesterol, can increase your risk of stroke and heart attack.
• Total cholesterol, the total amount of cholesterol in your blood based on your HDL, LDL, and triglycerides numbers.

Before the test, you may need to fast (not eat or drink) for 8 to 12 hours. Your doctor will let you know if fasting is necessary and provide any other special instructions. During the test, a health care professional will take a blood sample from a vein in your arm using a small needle. The procedure usually takes less than five minutes and may cause slight pain or bruising at the spot where the needle was inserted.

Cholesterol levels are typically measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. Your cholesterol levels, along with your family history, age, sex, and lifestyle, will help your healthcare team determine your risk for high cholesterol and any necessary steps to lower that risk.

Frequently asked questions