Cardiovascular Disease

The leading cause of death in Canada is cardiovascular disease. Its treatment represents a major cost to our health care system.

Cardiovascular disease is caused by a narrowing of arteries to vital body organs. When this narrowing occurs in the coronary arteries - the ones that supply the heart - it is called Coronary Heart Disease (CHD). Narrowing is due to atherosclerosis, which is caused when fibrous tissue and lipids (fats), particularly cholesterol, build up on artery walls. Blood clotting occurs more readily on these surfaces. When only narrowing exists, chest pain (angina) may occur with exertion - a possible warning sign of heart attack. When a blood clot forms in the narrowed coronary arteries, a blockage can occur and a heart attack is possible.

What encourages these cholesterol laden deposits to form on artery walls? Many experts believe that once an artery is injured, the repair process that follows leads to the formation of atherosclerotic lesions. The rate at which atherosclerosis develops is also determined, in part, by the level of lipids in the blood and their interplay with other risk factors for CHD.

One of the most important factors affecting the development of atherosclerosis is cholesterol concentration in the blood. Various studies show an increased risk of CHD with elevated levels of blood cholesterol. The risk diminishes as blood cholesterol levels decrease.

What Is Cholesterol?

Cholesterol is a necessary component of human cells. It is a waxy fat-like substance found in all animal derived foods, particularly eggs, organ meats, meat, fish and dairy products. The human liver is capable of making cholesterol from excess calories, especially from dietary fat. Dietary fat, particularly saturated fat, is the source of elevated levels of blood cholesterol for most people. Food derived from plants is free of cholesterol, and most plants are low in saturated fats although there are a few exceptions like avocados, macadamia nuts, cashew nuts, palm and coconut oils. Animal fats are largely saturated and are solid at room temperature. On the other hand, unsaturated fats like canola, corn, olive and safflower oils, are liquid at room temperature.

Most saturated fats, regardless of their source, increase blood cholesterol. Cholesterol in the blood is surrounded by a protein cover called lipoprotein. Blood cholesterol has three components:

• LDL Low-Density Lipoprotein
• HDL High-Density Lipoprotein
• VLDL Very Low-Density Lipoprotein

Most cholesterol circulates in the blood as LDL, also known as the 'bad cholesterol'. LDL cholesterol promotes atherosclerosis by transporting cholesterol into the artery wall while HDL (the 'good cholesterol'), is thought to transport cholesterol out of the artery wall. Therefore, high LDL cholesterol and low HDL cholesterol are risk factors for Coronary Heart Disease. Other lipid particles are also factors in the development of atherosclerosis.

People with no previous cardiovascular problems should strive for the following cholesterol levels:

Managing Cholesterol: Lifestyle

Risk factors that contribute to atherosclerosis include:

• High blood cholesterol
• Hypertension (high blood pressure)
• Cigarette smoking
• Sedentary lifestyle
• Obesity
• Age
• Family history of CHD

It is important to remember that elevated blood cholesterol levels must be accompanied by two or more additional risk factors to be considered at high risk for cardiovascular disease. Although some people have high blood cholesterol due to their genetics, most high levels can be traced to diet and lifestyle.

Changes in lifestyle can make a difference in blood cholesterol levels. The challenge is how best to introduce ourselves to a healthier way of living to bring about this change. Lifestyle patterns and living habits develop over many years; therefore, meaningful change will likely take some time to occur.

General principles that can be applied to the process of change:

• Set specific goals: make a contract with yourself and a friend or your doctor
• Establish a lifestyle pattern first, then build change within the pattern
• Monitor the rate of change - all or nothing seldom works
• Lifestyle is a choice - changes to lifestyle are made by choice.
• The new lifestyle should feel as routine as getting dressed in the morning
• Once the process of change has started, gradually fine tune your goals

Prioritize the risk factors mentioned earlier and develop your own strategy for change.

Managing Cholesterol: Diet & Exercise

Examine the fat content in your diet closely. Of all the components needing change in diet, the most important is the fat content - all fat. It is essential to reduce the intake of fat from all sources. No more than 30% of our energy intake should come from fat. Keep in mind that 1 gram of fat contains more than twice the calories of 1 gram of carbohydrate or protein. Dietitians and other health care practitioners can help you create a well balanced diet.

Moving to low fat foods can be achieved over time. The choices you make when purchasing dairy products, for example, are a good beginning. Low fat products such as skim or 1% milk, skim milk-based products such as cheese and low fat yogurt are good choices. A graded approach to lowering your fat intake may work best: if you are drinking homogenized milk now, switch to 2% milk for a while, then to 1%, and finally to skim milk.

We are creatures of habit and most of us tend to reuse our meal recipes. Examine your recipes closely to determine their fat content. Often only slight changes are required to significantly reduce the fat content in these recipes. There are also many great low fat cookbooks that can help make your diet changes easier and more enjoyable.

Another way to lower your dietary fat intake, is to look for the hidden fats in baked goods, ice cream, and processed foods and meats, and make trade-offs between food items. For example, a switch from whole milk to skim milk (250ml serving) will drop 60 calories or 7.7 grams of fat from your diet. Replace 20 frenchfries with one baked potato and a teaspoonful of margarine, and you'll reduce your fat intake by 44 calories or 5.7 grams. Regular Italian salad dressing (15ml) traded-off for a low-cal variety can drop the fat content by 7.7 grams or 70 calories.

Exercise is also a vital component to lowering blood cholesterol. Developing an exercise program that becomes a regular part of your lifestyle is essential to maintaining good blood cholesterol levels. A walking regime is an easy way to start and, of course, the price is right!

The blood cholesterol response to lifestyle, dietary, and exercise changes is variable and highly individualized, but is usually noticeable within a few weeks. Once you've set your goals, it's important to get support (and even participation!) from your family, so the gradual dietary change will become long lasting. Occasionally, even with the best of intentions, many people fail to bring real change over the long term. It is important to remember that real change occurs slowly, and is often accompanied by setbacks along the way. Don't become discouraged. Stay motivated and don't lose sight of your goals. Your good health is worth the effort!

Compiled by Bud Nistore
Dyck's Pharmacists, Kelowna, B.C.
Edited by Megan Stiles
Last Reviewed: September 2001