Heart disease and stroke are the primary causes of death in Canada, in addition to being significant causes of disability for both men and women, and include:
- disease due to cholesterol build-up in the blood vessels in the heart (coronary heart disease or CHD);
- disease of other blood vessels (cardiovascular disease or CVD), which includes the vessels going down to your stomach, kidneys and legs (peripheral vascular disease or PVD); and disease of the blood vessels going to your brain (carotid artery disease or CAD).
In the 1960s, scientists coined the term “risk factors” to describe the personal traits and lifestyle habits that can contribute to our chances of being affected by heart disease and stroke. Some risk factors we have little or no control over (e.g., our age, gender or a family history of premature heart disease). There are other risk factors that we can control (e.g., diabetes, obesity, elevated blood cholesterol and triglycerides, elevated blood pressure, metabolic syndrome) or even change – in particular, our lifestyle habits.
Too much food, too little exercise and smoking are the lifestyle habits that are primarily responsible for heart disease and stroke.
Blood lipids are fat-like substances in the blood, and include cholesterol, lipoprotein carriers of cholesterol and triglycerides (TG). The levels of lipids in the blood are affected by a combination of factors, including diet, obesity, lifestyle habits, hormone levels, genetic factors and drug use.
|Raises LDL-C||Lowers HDL-C||Raises Triglycerides|
|High saturated fat diet
High intake of dietary cholesterol
|Excess sugar and sweets
Excess refined carbohydrate
Poorly controlled diabetes
Cholesterol is produced primarily by your liver, although some of the cholesterol in your blood comes from the foods you eat. The most important types of cholesterol in the blood are:
- low density lipoprotein cholesterol (LDL-C), and
- high-density lipoprotein cholesterol (HDL-C).
LDL-C causes a build-up of cholesterol on the walls of your arteries that is known as plaque. Eventually, it can become so thick that it narrows the space in which blood moves – the lumen – and slows down or even blocks blood flow. Blocks can also occur when a piece of plaque breaks off. Angina – a chest tightness or pain in your left arm or jaw – is caused by poor blood flow in the heart muscle.
HDL picks up cholesterol from the walls of the arteries and returns it to the liver for recycling or excretion. The more HDL-C you have in your blood, the better protected you are against the build-up of plaque in your arteries.
Because there are no symptoms of high LDL-C or low HDL-C, only a blood test can tell your doctor whether or not your blood cholesterol levels are putting you at risk for heart disease or stroke.
Triglycerides (TG), are another type of fat in your blood- stream. The liver produces triglycerides from the foods that you eat. Foods that are high in fat, sugar and alcohol make the liver produce more triglycerides. Being overweight (especially if you carry too much fat around your midsection) also makes the liver produce more triglycerides. High TGs increase the chances of blood clots forming in your arteries and can also lower HDL-C (healthy cholesterol) levels.