"Heart disease" is a general term that includes coronary heart disease, congenital heart disease (a condition you're born with), congestive heart failure and malfunctioning heart valves. The following information discusses only coronary heart disease, a disease that affects the blood vessels that feed the heart.
What Causes Heart Disease?
Coronary heart disease is caused by atherosclerosis, a gradual process that narrows the heart's arteries and leads to a heart attack. Atherosclerosis can begin in adolescence, when fatty streaks can appear on the lining of arteries as cholesterol sticks to the arteries.. Over time, the fatty streaks enlarge and become hardened with minerals, tissue, fat and cells, forming plaques. As plaques form beneath the artery wall, they stiffen arteries and narrow the passage through them. Most people have well-developed plaques by the time they are 30 years old.
If atherosclerosis progresses, it can restrict blood flow to the heart. Blood cells called platelets respond to damaged spots on blood vessels by forming clots. A clot may stick to a plaque and gradually enlarge until it blocks blood flow to an area of the heart. That portion of the heart may die slowly and form scar tissue. But a clot can also break loose and circulate in the blood until it reaches an artery too small to pass through. When a clot that's wedged in a vessel cuts off the supply of oxygen and nutrients to a part of the heart muscle, a heart attack results.
Who’s at Risk?
Non-modifiable Risk Factors:
- You're over 40. You have a family history of heart attack prior to age 60.
Modifiable Risk Factors:
- You have high blood cholesterol.
- You have high blood triglycerides.
- You have low HDL cholesterol.
- You have high blood pressure.
- You smoke cigarettes.
- You have a poor diet.
- You don't exercise regularly.
- You have diabetes.
- Your body mass index (BMI) is greater than 25
Your Blood Cholesterol Levels
There are two kinds of cholesterol. Dietary cholesterol is found in foods, and your liver makes blood cholesterol. Cholesterol and fat are transported in your bloodstream on carrier molecules called lipoproteins. The lipoproteins that have received the most research attention are low-density lipoproteins (LDL), high-density lipoproteins (HDL) and triglycerides. If you know your cholesterol levels, use the following reference guide to determine if your level is healthy or if it puts you at higher risk for heart disease.
||Borderline Risk||At Risk
|Total cholesterol||< 5.2||5.2-6.2||> 6.2|
Blood lipids are measured in mmol per liter.
Circulating cholesterol contributes to heart disease by becoming part of the fatty plaques that build up on artery walls. The more LDL cholesterol in the blood, the more cholesterol available to attach to artery walls. The longer you have high LDL levels, the greater the chance more cholesterol has built up in your arteries. While LDL is considered bad, oxidized LDL cholesterol is deemed even worse. When LDL cholesterol is oxidized (damaged) by free radical molecules, it is more likely to accumulate in the arteries. Dietary antioxidants may help prevent such damage to LDL cholesterol particles.
The ratio of total cholesterol to HDL cholesterol is considered a better predictor of heart disease risk than LDL or HDL values alone. This measure is referred to as your risk ratio. Here's a reference guide:
Total/HDL Cholesterol (Risk Ratio)
|Much above average||10.0|
Nutrition Strategies for Preventing Heart Disease
Many of the risk factors for heart disease are influenced by what you eat. The nutrition and herbal recommendations below can keep your blood cholesterol at a healthy level, prevent damage or oxidation to your LDL cholesterol and promote weight loss.
1. Reduce your intake of saturated and trans fats
One of the most important strategies for keeping total and LDL cholesterol levels within the healthy range is to reduce your fat intake to no more than 30 percent of your total daily calorie intake. If you consume 2000 calories per day, that means consuming no more than 65 grams of fat. If you follow a 1200-calorie weight-loss diet, consume no more than 40 fat grams per day.
Not all types of dietary fat affect your blood cholesterol the same way. Some fats have a strong impact on the risk for heart disease, whereas others are neutral and don't affect risk.
Saturated fats are solid at room temperature. This is the type of fat found in animal foods - meat, poultry, eggs and dairy products. Diets high in saturated fat raise the risk for heart disease by increasing the level of blood cholesterol. Foods contain many types of saturated fats, and not all of them influence blood cholesterol levels to the same degree. For instance, the saturated fat in dairy products is more cholesterol-raising than the saturated fat in meat. What's most important is to eat less saturated fat, period.
||Lower fat choices or substitutes|
|Milk||Skim, 1% milkfat (MF)|
|Yogurt||Products with less than 1.5% MF|
|Cheese||Products with less than 20% MF|
|Cottage Cheese||Products with 1% MF|
|Sour Cream||Products with 7% MF or less|
|Cream||Evaporated 2% milk or evaporated skim milk|
|Red meat||Flank steak, inside round, sirloin, eye of round, extra lean ground beef, venison|
|Pork||Centre cut pork chops, pork tenderloin, pork leg (inside round, roast), baked ham, deli ham, back bacon|
|Poultry||Skinless chicken breast, turkey breast, ground turkey|
|Eggs||Egg whites (2 whites replaces one egg). You can buy these right beside the fresh eggs in your grocery store.|
Hydrogenation is a chemical process that adds hydrogen atoms to liquid vegetable oils. This makes vegetable fats more solid and more useful to food manufacturers. Packaged foods like cookies, crackers and baked goods made with partially hydrogenated vegetable oils are more palatable and have a longer shelf life. Stick margarines made by hydrogenating a vegetable oil are firm like butter.
When a vegetable oil is partially hydrogenated, it becomes saturated and it forms a new type of fat called trans fat. Trans fat increases LDL cholesterol and decreases HDL cholesterol. Many researchers believe that trans fat is worse for our cholesterol levels than saturated fat.
To help reduce your intake of trans fat, start reading food labels and ingredients lists. Look for the words 'partially hydrogenated vegetable oils.' Eat foods that contain these types of oils less often. As much as 40 percent of the fat in foods like French fries, deep-fried fast food, doughnuts, pastries, snack foods and commercial cookies is trans fat. If you eat margarine, choose one that's made with non-hydrogenated fat. Many brands state this right on the label.
Soon prepackaged foods will list the grams of trans fat on their nutrition labels. In the fall of 2000, Health Canada announced recommendations for improved nutrition labels on foods. All prepackaged foods will have to disclose nutrition facts on the label for a greater number of nutrients, including trans fat. Once these recommendations become law (expected late 2001), food manufacturers will have two years to fully conform to the new nutrition labeling laws.
2. Moderate your intake of dietary cholesterol.
This wax-like fatty substance is found in meat, poultry, eggs, dairy products, fish and seafood. It's particularly plentiful in shrimp, liver and egg yolks. While high-cholesterol diets cause high blood cholesterol in animals, this is not the case in humans. Dietary cholesterol has little or no effect on most people's blood cholesterol. A study from Harvard University did not find any significant association between egg intake and risk of heart disease or stroke in healthy men and women. Eating one egg per day will not affect your risk for heart disease.
Too much dietary cholesterol can raise levels of LDL cholesterol in some people, especially people with hereditary forms of high cholesterol. Health Canada recommends that we consume no more than 300 milligrams of cholesterol each day. Choosing animal foods that are lower in saturated fat also helps to cut down on dietary cholesterol.
3. Eat more soy foods.
A large body of evidence has shown that a low-fat diet containing 25 grams of soy protein per day lowers the risk for heart disease. A report in the New England Journal of Medicine analyzed 38 studies and determined that eating soy protein instead of animal protein significantly lowered high levels of LDL cholesterol and triglycerides. Since then, a number of other studies have confirmed soy's cholesterol-lowering ability.
A regular intake of soy may also raise HDL cholesterol, lower high blood pressure and keep blood vessels healthy. Natural compounds in soybeans seem to act as antioxidants, preventing oxygen damage to LDL cholesterol.
To add soy protein to your low-fat diet each day, use the following guide:
||Food Soy Protein (grams)
|Soy beverage, 1 cup (250 ml)||9 g|
|Soybeans, canned, 1/2 cup (125 ml)||14 g|
|Soy nuts, 1/4 cup (60 ml)||14 g|
|Soy flour, defatted, 1/4 cup (60 ml)||13 g|
|Soy protein powder, isolate, 1 scoop||25 g|
|Tempeh, 1/2 cup (125 ml)||16 g|
|Tofu, firm, 1/2 cup (125 ml)||19 g|
|Tofu, regular, 1/2 cup (125 ml)||10 g|
|Veggie Burger, Yves Veggie Cuisine||11 g|
|Veggie Dog, small, Yves Veggie Cuisine||11 g|
4. Boost your intake of soluble fiber.
Soluble fiber has been shown to lower high blood cholesterol levels. Studies show that adding oats and beans to your diet can lower cholesterol by up to 16 percent. And eating a psyllium-enriched breakfast cereal has been shown to lower LDL cholesterol by 9 percent. The best food sources of these fibers include oats and oat bran, psyllium-enriched breakfast cereals, legumes and certain fruits and vegetables.
The following foods are good sources of soluble fiber:
|Oat bran||Black beans||Grapefruit
|Kellogg's All||Chickpeas||Apple||Sweet potatoes|
|Bran Buds||Lentils||Strawberries||Green peas|
|Psyllium- enriched cereals||Soybeans||Pears|
If you've decided to try a psyllium-rich breakfast cereal, start with a small portion. Too much too soon can cause bloating and gas. It usually takes two weeks for the bacteria that reside in the intestine to adjust to a higher fiber intake. Start by adding 1/4 to 1/2 cup (60 to 125 ml) of Kellogg's All Bran Buds to your usual breakfast cereal. Over the course of two or three weeks, increase your portion. Increase fluid intake as you consume more fiber, since fiber needs fluid to exert its effect.
5. Get more vitamin C.
Many studies have reported a link between high dietary intakes and high blood levels of vitamin C and a lower risk of heart disease. Vitamin C may protect from heart disease by acting as an antioxidant. The vitamin is able to neutralize harmful free radical molecules that damage your LDL cholesterol. Studies also suggest vitamin C may inhibit the formation of blood clots by reducing the stickiness of platelets.
The best sources of vitamin C include citrus fruit, citrus juices, cantaloupe, kiwi, mango, strawberries, broccoli, Brussels sprouts, cauliflower, red pepper and tomato juice. To supplement, take a 500 milligram supplement of Ester C daily. If you want to take more, split your dose over the course of the day. Some multivitamin and mineral supplements supply up to 250 milligrams.
6. Consider extra vitamin E.
Many studies suggest that vitamin E supplements can help prevent heart attacks in healthy men and women. Vitamin E is a potent antioxidant. Once consumed through the diet or a supplement, vitamin E makes its way to the liver, where it is incorporated into the lipoproteins that transport cholesterol. It is here that vitamin E works to protect these compounds from oxygen damage caused by free radicals. The best food sources of vitamin E include wheat germ, nuts, seeds, vegetable oils, whole grains and kale. To supplement, take 200 to 800 international units (IU) of natural source vitamin E. Buy a 'mixed' vitamin E supplement if possible. Do not take vitamin E supplements if you use a blood-thinning medication such as warfarin (Coumadin). Do not take vitamin E supplements if you have diabetes or existing heart disease.
7. Go for garlic.
Garlic contains many different sulfur compounds, and one in particular, S-allyl cysteine (SAC), has been shown to lower LDL cholesterol by up to 10 percent. SAC is present in small amounts in raw garlic, but increases in concentration when garlic ages. Studies have shown that garlic can also lower blood triglyceride levels and thin the blood by reducing the stickiness of platelets. The sulfur compounds in aged garlic extract also act as antioxidants and prevent damage to LDL cholesterol.
Scientists agree that as little as half a clove of garlic each day will offer health benefits. Add garlic to sauces, soups, casseroles and salad dressings. Most people can take one or two cloves a day without any problems. Some people, however, experience stomach upset when they eat raw garlic. The oil-soluble compounds in garlic account for its potential to irritate the stomach and to cause odor.
When it comes to garlic supplements, the scientific research points to aged garlic extract as the supplement of choice because of its higher concentration of SAC. Generally, two to six capsules a day (one or two with each meal) are recommended.
Recommended Resources on the Web
Heart and Stroke Foundation of Canada
American Heart Association
The above an excerpt from "Leslie Beck's Nutrition Encyclopedia" (Penguin Canada, 2001/2003), available at bookstores across the country. The following is copyrighted and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or means - electronic, mechanical, photocopying, or likewise.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.