Fats are one of the three main classes of foods, along with proteins and carbohydrates. The body needs some fat to use vitamins and keep skin healthy. Fats are a source of energy for the body - one gram of fat provides nine calories. No more than 30 per cent of your total daily calories should come from fat.
Chest pain that results from restricted blood flow in the coronary arteries. Blood flow does not meet the oxygen needs of the heart muscle.
The coronary arteries are on the surface of the heart. They provide blood to the heart muscle itself.
Coronary heart disease
This is the most common form of heart disease. Narrowing or blocking of the coronary arteries causes reduced blood supply to the heart muscle. It is often characterized by myocardial infarction (heart attack), angina pectoris (chest pain), and atherosclerosis in the coronary arteries.
A general term that refers to any disease or condition of the heart. Usually occurs due to inadequate blood flow to the heart muscle, which is typically caused by atherosclerosis.
High blood pressure (also called hypertension). A risk factor for heart disease.
A medical term for heart attack.
Cholesterol is a waxy, fat-like substance found in every cell in the body. The body makes its own cholesterol in the liver. It is also in many foods. Cholesterol is in the blood, mostly in the form of either LDL or HDL cholesterol. Some cholesterol in the blood is necessary, but too much can lead to heart disease.
In atherosclerosis (a type of hardening of the arteries), cholesterol, fat, and other blood components build up on artery walls. As the condition progresses, the coronary (heart) arteries may narrow. The flow of oxygen and nutrient-rich blood to the heart muscle is reduced.
The lipid profile is one measure of the risk of coronary heart disease. It is actually a group of tests. This blood test measures total cholesterol, triglycerides, and HDL cholesterol. LDL cholesterol can be calculated from the results.
Total cholesterol - The total amount of cholesterol carried in the blood, whether by HDL, LDL, or another carrier. This measure does not distinguish between HDL cholesterol and LDL cholesterol.
HDL cholesterol - High-density lipoprotein (HDL) cholesterol is referred to as the 'good' cholesterol. It acts as a scavenger, removing excess cholesterol from artery walls. High levels of HDL are associated with a decreased risk of heart disease.
Triglycerides - A blood fat that may also be related to a higher risk of heart disease. Consuming excess sugary foods, fatty foods and alcohol can elevate triglyceride levels.
LDL cholesterol - Low-density lipoprotein (LDL) cholesterol is referred to as the 'bad' cholesterol. If too much LDL circulates in the blood, cholesterol may be deposited in the artery walls. This contributes to atherosclerosis and an increased risk of heart disease.
These levels in the blood reliably indicate the risk of heart attack or stroke. In a heart attack, one of the coronary arteries becomes blocked. The blood supply to part of the heart muscle is then severely reduced or stopped. The obstruction is often made up of plaque from atherosclerosis. In a stroke, damage to a part of the brain results when the blood vessels supplying that part of the brain become blocked. Blockage can also be caused by atherosclerosis. As you can appreciate, anything that can be done to reduce the risk of a heart attack or stroke is a good thing.
Since the numbers in a lipid profile are so important, it is vital that you understand them. Rather than just knowing that they are low, normal or high, always ask your health care provider for the actual numbers. Write down and keep a record (see Table 2) of these numbers, just like you would with your blood pressure readings.
Another measurement sometimes used is the Total Cholesterol: HDL-Cholesterol Ratio (TC/HDL). To get this number, the total cholesterol blood level is divided by the blood level for HDL-Cholesterol (the good cholesterol).
Table 1 shows when treatment should be started as well as LDL targets based on a person's risk of heart disease. Be sure to discuss your particular target levels with your doctor.
Table 1. Target Lipid Levels - Initiate Treatment When:
|People with Low Risk of Heart Disease||People with Moderate Risk of Heart Disease||People with High Risk of Heart Disease|
|Initiate treatment when LDL level is||Greater than 5 mmol/L||Greater than 3.5 mmol/L
or TC/HDL less than 5 mmol/L or HS-CRP greater than 2 mg/L
in men greater than 50 years
women greater than 60 years
|Consider treatment for all patients.|
|Primary target||Greater than or equal to 50% reduction in LDL||Less than 2 mmol/L or greater than or equal to 50% reduction in LDL||Less than 2 mmol/L or greater than or equal to 50% reduction in LDL|
C-Reactive protein is produced in the liver. Levels rise when there is inflammation in the body. High CRP levels are linked to heart disease.
Note on units: In Canada, lipid measurements are recorded in mmol/L. In the USA, they are recorded in mg/dL. To convert mmol/L, you must multiply by 39 for cholesterol and by 89 for triglycerides. To convert from mg/dL you would instead divide by that number. This information may come in handy if you are researching lipids on the internet, since many articles are written for an American audience and so use mg/dL.
When the lipid profile shows numbers that are not within your target range, action must be taken to move these numbers to acceptable levels. This reduces your risk factors for heart disease and increases your chances of living a longer, healthier life. Risk factors are anything that increases your risk of suffering from the effects of heart disease. They are both modifiable and non-modifiable.
These fats mainly come from plants. They can be further broken down into polyunsaturated and monounsaturated fats.
This unsaturated fat can be found in canola, olive and peanut oil, and also in avocados. It is the preferred dietary choice among the fats. Eating food that has more monounsaturated fat, instead of saturated fat, may help lower LDL cholesterol and reduce heart disease risk. Unlike polyunsaturated fats, it does not appear to have a negative affect on HDL cholesterol levels.
These unsaturated fats are usually a major part of oils from certain vegetables (corn, soybean), seeds (such as sunflower, sesame, safflower) and margarine. They do not appear to raise the bad LDL cholesterol levels, and so are preferable over saturated fats. Unfortunately though, they may also lower the good HDL cholesterol level.
Omega-3 fatty acids
This type of polyunsaturated fat is commonly found in fish and fish oils. When eaten in moderate quantities it is thought to reduce the risk of coronary heart disease in some people.
These fats are found in animal foods, hydrogenated vegetable oils, and some dairy products. They speed up the liver's production of bad LDL cholesterol. Restricting daily calorie intake of saturated fats to no more than 10 per cent is recommended.
Trans fats or hydrogenated fat
These are vegetable oils that have been changed to increase their shelf life, flavor and stability. They are frequently used in fast foods and snack foods. They raise the bad LDL cholesterol, and are as bad for us as saturated fats and possibly worse.
Health Canada is working with food and restaurant industries to limit trans-fat content in all food products.
Modifiable risk factors for heart disease are those that we can change or prevent to reduce the risk of suffering a heart attack, stroke or similar event. They include diabetes, atherosclerosis, hypertension, angina, smoking, obesity, stress, and inactivity.
Non-modifiable risk factors for heart disease are those that we cannot change. They include family history, age, peripheral vascular disease, previous heart attack or stroke, and previous bypass surgery or angioplasty.
Cholesterol is one of the modifiable risk factors for heart disease. Every time you reduce your LDL cholesterol level by one per cent, you reduce your risk of heart disease by two per cent. Lowering cholesterol is an excellent way to significantly reduce your risk of suffering from heart disease.
The most important way to lower blood cholesterol levels involves diet and weight management. The Canada Food Guide offers a reliable outline for healthy eating. You can make changes on your own or talk with a dietitian. Making better food choices also involves reading food labels effectively. Learn how to tell the difference between saturated, polyunsaturated and monounsaturated fats, trans fats and Omega-3 fats.
General dietary rules can make a big difference. Aim to keep total calories from fat at less than 30 per cent of your total intake. Saturated fats and trans fats should be less than ten per cent of your total intake. Cholesterol intake should be less than 300 milligrams per day.
In addition to eating properly, regular physical activity is essential. At least one study has shown that the benefits of a low-fat diet are lost if not combined with an activity program. Canada's Guide to Physical Activity recommends a daily total of one hour of light activities in segments of at least ten minutes long. Remember to vary the kinds of activities you do. Exercise not only lowers bad LDL cholesterol, it raises the good HDL cholesterol.
Depending on the results of your lipid profile, medication may be recommended to help reduce your cholesterol levels. Lipid medications in use today include statins, fibrates, ezetimibe, bile-acid sequestrants and niacin. Each kind of drug has different effects on the body. Sometimes they are used together, so it is not unusual to take more than one of these medications. The choice of drug depends on whether you need to reduce LDL cholesterol, increase HDL cholesterol, reduce triglycerides or achieve some combination of the three.
Bile-acid sequestrants are used to reduce LDL cholesterol and triglycerides. They bind with bile acids in the intestine. They are usually only used for mildly elevated LDL cholesterol levels. Questranª (cholestyramine) is one product available.
Ezetimibe (brand name Ezetrolª) is the newest class of lipid-lowering medication. It inhibits the absorption of cholesterol from the intestine, helping to lower LDL cholesterol. This medication has very few side effects.
Fibrates help lower lipid levels when elevated triglycerides are the primary concern. They lower triglycerides and raise HDL cholesterol. They include Bezalipª (bezafibrate), Lipidilª (fenofibrate), and Lopidª (gemfibrozil).
Niacin is also known as vitamin B3 or nicotinic acid. The main effect of niacin is to increase HDL levels and decrease triglycerides. It also has a modest effect on LDL levels. Niacin is mainly used when LDL levels are high with low HDL levels or alternatively when LDL levels are normal with increased triglyceride levels.
Statins are commonly used medications for reducing cholesterol. They are also known as HMG-CoA reductase inhibitors. Statins help the liver decrease cholesterol production, and are very effective at reducing LDL cholesterol. They include the drugs Crestorª (rosuvastatin), Lescolª (fluvastatin), Lipitorª (atorvastatin), Mevacorª (lovastatin), Pravachol (pravastatin), and Zocorª (simvastatin).
Talk to your doctor and your pharmacist to understand your medications as thoroughly as possible. Your pharmacist's primary job is to make sure you understand what medications you are taking, why you are taking them, and what effects they can have on you.
Becoming actively involved in your own health can make a big difference. Understanding the effects fat and cholesterol levels have on your body is a key part of managing your health. Talk to a healthcare professional to get the help you need.