Cholesterol is a waxy substance that comes from two sources: your body and food. Your body, and especially your liver, makes all the cholesterol you need and circulates it through the blood. But cholesterol is also found in foods from animal sources, such as meat, poultry and full-fat dairy products. Your liver produces more cholesterol when you eat a diet high in saturated and trans fats.
Excess cholesterol can form plaque between layers of artery walls, making it harder for your heart to circulate blood. Plaque can break open and cause blood clots. If a clot blocks an artery that feeds the brain, it causes a stroke. If it blocks an artery that feeds the heart, it causes a heart attack.
There are two types of cholesterol: “good” and “bad.” Too much of one type—or not enough of another—can put you at risk for coronary heart disease, heart attack or stroke. It’s important to know the levels of cholesterol in your blood so that you and your doctor can determine the best strategy to lower your risk.
Making healthy eating choices and increasing exercise are important first steps in improving your cholesterol. For some people, cholesterol-lowering medication may also be needed to reduce the risk for heart attack and stroke. Use the information provided here to start a conversation with your doctor about how cholesterol affects your heart attack and stroke risk and what you can do to lower your risk.
Good vs. Bad Cholesterol
Cholesterol can’t dissolve in the blood. It must be transported through your bloodstream by carriers called lipoproteins, which got their name because they’re made of fat (lipid) and proteins.
The two types of lipoproteins that carry cholesterol to and from cells are low-density lipoprotein, or LDL, and high-density lipoprotein, or HDL. LDL cholesterol and HDL cholesterol, along with one-fifth of your triglyceride level, make up your total cholesterol count, which can be determined through a blood test.
LDL (Bad) Cholesterol
LDL cholesterol is considered the “bad” cholesterol because it contributes to plaque, a thick, hard deposit that can clog arteries and make them less flexible. This condition is known as atherosclerosis. If a clot forms and blocks a narrowed artery, heart attack or stroke can result. Another condition called peripheral artery disease can develop when plaque buildup narrows an artery supplying blood to the legs.
HDL (Good) Cholesterol
HDL cholesterol is considered “good” cholesterol because it helps remove LDL cholesterol from the arteries. Experts believe HDL acts as a scavenger, carrying LDL cholesterol away from the arteries and back to the liver, where it is broken down and passed from the body.
One-fourth to one-third of blood cholesterol is carried by HDL. A healthy level of HDL cholesterol may also protect against heart attack and stroke, while low levels of HDL cholesterol have been shown to increase the risk of heart disease.
Triglycerides are another type of fat, and they’re used to store excess energy from your diet. High levels of triglycerides in the blood are associated with atherosclerosis. Elevated triglycerides can be caused by excess weight and obesity, physical inactivity, cigarette smoking, excess alcohol consumption and a diet very high in carbohydrates (more than 60 percent of total calories). Underlying diseases or genetic disorders are sometimes the cause of high triglycerides. People with high triglycerides often have a high total cholesterol level, including a high LDL (bad) cholesterol level and a low HDL (good) cholesterol level. Many people with heart disease or diabetes also have high triglyceride levels.
Lp(a) is a genetic variation of LDL (bad) cholesterol. A high level of Lp(a) is a significant risk factor for the premature development of fatty deposits in arteries. Lp(a) isn’t fully understood, but it may interact with substances found in artery walls and contribute to the buildup of fatty deposits.
Talk with your healthcare provider about assessing your risk for a heart attack or stroke. Cholesterol levels are an important factor in estimating your personal risk.
Visit your healthcare provider to create an action plan that will help you make important lifestyle changes. Sometimes, medication is needed in addition to a healthy diet and lifestyle.
Visit www.heart.org for more information about cholesterol, prevention tips and treatment options.
—Courtesy of the American Heart Association