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(Adapted from the Heart and Stroke Foundation of Canada and the American Heart Association)


Also called arteriosclerosis, atherosclerosis is the process where y our arteries become clogged with fatty deposits – also known as plaques - along the inner walls. This causes your arteries to lose their elasticity and become narrow, eventually blocking the smooth flow of blood.

Arterial plaque is a sticky, yellow substance made up of fatty materials such as cholesterol, and also calcium and waste products from your cells. Atherosclerosis is a slow, progressive condition that may begin as early as childhood. It affects large and medium-sized arteries anywhere in the body, but can lead to symptoms when it affects arteries supplying the heart, brain and limbs.

Heart attack

A heart attack occurs when atherosclerosis leads to complete blockage of a coronary artery that supplies blood to the heart muscle. The heart muscle is literally starved of oxygen and nutrients, leading to symptoms such as chest discomfort, shortness of breath, nausea, palpitations and irregular heart rhythm, loss of consciousness and sometimes sudden death.

Atherosclerosis causes more than 90% of heart attacks. A heart attack may also occur when a coronary artery temporarily contracts or goes into a severe spasm, effectively shutting off the flow of blood to the heart. The length of time the blood supply is cut off will determine the amount of damage to the heart.


A stroke is a sudden loss of brain function. There are two ways this can happen. Most commonly, an ischemic stroke occurs when the blood flow to the brain is interrupted by plaque or clot. Less commonly, a hemorrhagic stroke occurs when the blood vessels within the brain burst. The interruption of blood flow or the rupture of blood vessels causes brain cells (neurons) in the affected area to die.

The effects of a stroke depend on the location of the injury within the brain, as well as how much damage occurred. A stroke can affect any number of areas, including your ability to see, move, speak, remember, reason, read, and write.


A lipid is a fatty substance that can't be dissolved in blood. Well known types of lipids in your blood include cholesterol and triglycerides. Abnormal lipid levels can contribute to atherosclerosis, leading to heart disease and stroke.


Cholesterol is a waxy fat-like substance that is found in the cells of the body. Your body needs some cholesterol to make hormones and substances that help digest food. While about 10-15% of cholesterol in the blood comes from the foods you eat, your liver makes most of the cholesterol you need and circulates it through your bloodstream. Dietary cholesterol comes from animal sources, such as meat, poultry and dairy products. Your liver also produces more cholesterol when you eat a diet high in saturated and trans fats.


Triglycerides are a type of fat that circulates in your blood. High triglycerides are often associated with excess weight, excess alcohol consumption and diabetes. The amount of triglycerides in your blood is commonly measured at the same time as your blood cholesterol. High levels of triglycerides in the blood increase the risk of heart attack and stroke, and very high levels can cause a condition called pancreatitis.


Lipids are transported in the blood inside particles called lipoproteins. Low-density lipoprotein (LDL), also known as "bad cholesterol", carries cholesterol out of the liver through the arteries and into the body. When LDL levels are high, these particles can get stuck on the inner wall of the arteries, leading to atherosclerosis. High LDL levels can be caused by genetic factors, poor diet and some medication conditions. High-density lipoprotein (HDL), also called "good cholesterol" acts like a sponge to mop up bad cholesterol from the arterial wall, bringing it back to the liver. Higher levels of the desirable HDL can be achieved by following a good diet, quitting smoking, exercise, and weight loss.