Before your doctor considers placing you on cholesterol-lowering medication, you will probably be urged to modify your diet in ways that can improve your blood cholesterol and triglyceride levels. Rather than following one fad diet after another, you will be urged to eat sensibly —reducing your intake of red meat and other foods high in saturated fats, choosing nonfat or low-fat dairy products, increasing your intake of fruits and vegetables, and consuming more fiber from foods like beans and oats.
In fact, some diets can lower LDL cholesterol almost as much as a cholesterol-lowering medication. In one study, participants who ate a diet low in saturated fat and rich in plant sterols (from vegetables, fruits, and vegetable oils), fiber (from oats and barley), soy protein, and almonds reduced their LDL cholesterol by an impressive 29%.
Dietary Fat and Cholesterol
The average American gets about 33% of his or her calories from fat. Not all of this fat is bad—in fact, some types of fat, such as monounsaturated and polyunsaturated fats, have a beneficial effect on blood lipids and may lower the risk of having a heart attack or dying of one. But the most prevalent fat in the American diet is saturated fat, the major dietary factor that raises blood cholesterol levels. In fact, saturated fat has a much bigger impact on blood cholesterol levels than dietary cholesterol.
The latest dietary advice from the American Heart Association is described below. You should follow these recommendations even if your blood cholesterol levels are normal.
Total Fat
Limit your total fat consumption to 25 to 35% of total calories. Taking this step helps to lower not only your LDL cholesterol levels but also your weight. That’s because fat contains more than twice as many calories (9 calories per gram) as carbohydrates or protein (4 calories per gram). Keep in mind, however, that fat and protein are more filling than carbohydrates. Don’t get too carried away with restricting fat in your diet. Lowering fat intake to 15% or less of total calories does not reduce LDL cholesterol levels much further than the standard low-fat diet. In addition, a very-low-fat diet can decrease HDL cholesterol and increase triglyceride levels.
Saturated Fat
The simplest dietary measure to lower your risk of a heart attack is to limit saturated fat intake to less than 7% of total calories. Reaching this goal will help reduce your blood cholesterol levels —specifically LDL cholesterol. Saturated fat is found in most animal and dairy foods and in palm and coconut oils.
Cholesterol
Your cholesterol intake should be less than 300 mg per day. Cholesterol is found only in foods of animal origin, such as organ meats (for example, liver), egg yolks, and the flesh of all animals (beef, poultry, fish, lamb, and pork). Certain shellfish (such as shrimp) also contain large amounts of cholesterol. Plant foods like vegetables, fruits, and grains contain no cholesterol.
Monounsaturated Fat
When consuming fat, choose monounsaturated fat over saturated fat whenever possible. Olive and canola oils, almonds, and avocados contain large amounts of monounsaturated fat. When substituted for saturated fat in the diet, monounsaturated fats lower LDL cholesterol levels and stabilize (and sometimes raise) HDL cholesterol levels.
Polyunsaturated Fat
This type of fat is found in safflower, sunflower, and corn oils and, like monounsaturated fat, can lower LDL cholesterol levels when consumed instead of saturated fat. In fact, replacing saturated fat with polyunsaturated fats may have a greater effect on reducing heart attack risk than substituting saturated fat with monounsaturated fat.
A type of polyunsaturated fat called omega-3 fat has additional heart-protective benefits. There are three major types: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha- linolenic acid (ALA). EPA and DHA, found only in fish (particularly fatty fish), reduce the tendency of the blood to clot, decrease the risk of abnormal heart rhythms (arrhythmias), and lower triglyceride levels. Small amounts of ALA, present in plant foods, can be converted to heart-healthy EPA and DHA. However, the heart benefits of ALA are uncertain.
You should consume fish (especially fatty fish) at least twice a week to receive the heart-protective effects of omega-3 fat. Coldwater, fatty fish like salmon, mackerel, trout, and herring are the best sources of omega-3 fat. You can also get omega-3 fat from fish oil supplements and a prescription drug called Lovaza (omega-3- acid ethyl esters).
Trans Fat
As with saturated fat, you should minimize your intake of trans fat —found primarily in foods made with partially hydrogenated oils. Some examples are stick margarines, commercial baked goods, and fried fast-foods. Trans fats are created when food manufacturers add hydrogen atoms to unsaturated vegetable oils to make them more saturated and thus more solid and shelf stable at room temperature.
Trans fat is harmful to your heart because it not only raises LDL cholesterol but also lowers HDL cholesterol levels. You should limit your intake of trans fat to less than 1% of total calories. The FDA requires manufacturers to list trans fat amounts on food labels. But beware: Even products labeled trans fat free can contain a small amount of trans fat (up to 0.5 mg per serving). So check the ingredient list. If a food contains no partially hydrogenated oils or shortening, it is truly trans fat free.
Sodium and Potassium
Following a diet low in sodium but high in potassium can help lower blood pressure and, in turn, reduce your risk of a heart attack.
Sodium
The typical American consumes 3,000 to 5,000 mg of sodium a day —much more than the body needs. When the kidneys cannot efficiently eliminate this excess sodium, the volume of blood that flows through your circulatory system increases. The extra pressure that the larger blood volume puts on your arteries causes blood pressure to rise. If you simply stop adding salt to the food you eat, you can lower your systolic blood pressure by 2 to 5 mm Hg and your diastolic blood pressure by 1 to 3 mm Hg on average. Restricting sodium is particularly effective in reducing blood pressure in older people with high blood pressure.
You should consume no more than 2,300 mg of sodium per day (which is equivalent to a little more than a teaspoon of table salt daily). If you have high blood pressure, you should aim for less than 1,500 mg of sodium a day.
Salt added to food during cooking or at the table is an obvious source of dietary sodium (salt is made up of 40% sodium and 60% chloride). But you should do more than just free yourself from the salt shaker. Sodium occurs naturally in many foods and, more importantly, is used extensively in food processing. For example, cold cuts, canned vegetables and soups, cheeses, and snack foods can all be concentrated sources of sodium. Check food labels carefully for the amount of sodium. When buying packaged or processed foods, choose the low- or no-salt versions when possible.
Potassium
Studies show that a diet high in potassium can lower blood pressure and reduce the rise in blood pressure caused by dietary sodium. If you have high blood pressure, you should increase your intake of fresh fruits and vegetables, which are rich in potassium and have the added benefit of being low in sodium and high in dietary fiber (see below) and antioxidants. Citrus fruits and bananas are particularly good sources of potassium, as are spinach, winter squash, and lima beans.
You should consume at least 4.7 g of potassium a day. You can reach this level by eating the recommended 2 cups each of fruits and vegetables a day. Potassium supplements are available but are not recommended for lowering blood pressure because they can be dangerous for people with kidney disease.
Fiber
You should try to eat at least 25 to 30 g of fiber a day. Fiber is a complex carbohydrate found only in plant foods, primarily whole grains, legumes, fruits, and vegetables. Because fiber is resistant to digestive enzymes, it passes through the digestive tract without being absorbed and is eliminated in stool.
Fiber comes in two forms: soluble, the type in oatmeal that gets sticky when wet; and insoluble, the sponge-like version in bran and fruit and vegetable skins that absorbs water. Both types of fiber are important, but soluble fiber is especially effective in lowering blood cholesterol levels. Just how soluble fiber reduces cholesterol levels is unclear. But researchers theorize that soluble fiber interferes with the intestinal reabsorption of substances called bile acids, which are produced from cholesterol in the liver. Bile acids that are not reabsorbed are eliminated from the body in stool. As a result, the liver ends up converting more cholesterol into bile acids.
It’s best to get your fiber from foods, because they contain a variety of other nutrients. Good sources of soluble fiber include oats, oat bran, barley, legumes, dried plums (prunes), apples, carrots, and grapefruit. Whole grains( like whole wheat, barley, brown rice, and quinoa), seeds, and most vegetables are rich in insoluble fiber. For people who find it difficult to get enough fiber in their diet, regular use of products that contain fiber from psyllium seeds—such as Metamucil—can lower cholesterol levels by 5 to 10%.
Stanols and Sterols
Stanols and sterols are found in small amounts in plant foods such as fruits, vegetables, grains, legumes, and nuts. These substances are similar in structure to cholesterol and interfere with cholesterol absorption from the small intestine, helping reduce total and LDL cholesterol levels.
Individuals with elevated LDL cholesterol levels should consider including 2 g of stanols or sterols in their diet each day. The amounts in plant foods are too small to accomplish this, but a number of foods are fortified with stanols and sterols in sufficient amounts. These foods include certain brands of margarine, orange juice, yogurt, and granola bars. When used in combination with a low-saturated-fat, low-cholesterol diet, these foods can help lower LDL cholesterol levels by 7 to 14%. However, don’t forget that stanol- and sterol-fortified foods contain calories and can cause weight gain when consumed in large quantities or in addition to your usual diet.
Soy
Soy is another food component to consider in your efforts to prevent a heart attack. Even though research shows that eating foods high in soy protein lowers LDL cholesterol levels by a mere 3%, choosing soy-containing foods (for example, soymilk and tofu) can still be beneficial for your heart. That’s because people who eat soy products tend to consume them instead of foods like meat and full-fat dairy products, which are high in both saturated fat and cholesterol.
Antioxidants
Numerous studies show that a diet rich in fruits and vegetables reduces heart attack risk. Some experts have attributed this benefit to antioxidants—naturally occurring substances that are plentiful in fruits and vegetables. Antioxidants help the body neutralize cell-damaging free radicals, which are normal byproducts of metabolism that can increase the risk of a heart attack, most likely by accelerating the development of atherosclerosis.
The most common antioxidants in the diet are vitamin E, vitamin C, and beta-carotene (which is converted to vitamin A in the body). A high intake of these antioxidants from food is associated with a lower risk of heart attacks. However, studies have shown no beneficial effect of antioxidant supplements on heart attack risk, and in some studies high doses of these supplements have been found to be dangerous. In addition, beta-carotene supplements can increase the risk of lung cancer in smokers.
As a result, supplements of vitamin E, vitamin C, and betacarotene are not recommended. (It’s still okay to take your daily multivitamin, since the antioxidant levels it contains are not high enough to cause harm.) The best way to get your antioxidants is to eat a diet rich in fruits and vegetables. Good dietary sources of vitamin C include broccoli, oranges, grapefruits, strawberries, cauliflower, spinach, potatoes, and cantaloupe. Vitamin E can be found in vegetable oils (such as sunflower, soybean, safflower, and corn), green leafy vegetables, whole grains, wheat germ, and nuts. For beta-carotene, consume carrots, sweet potatoes, spinach, broccoli, oranges, papayas, and apricots.
Other Nutritional Supplements: Fish Oil
In addition to the antioxidant supplements mentioned above, a number of other supplements have been studied as possible allies in the fight against heart attacks. For example, folic acid supplements lower blood levels of homocysteine; however, multiple studies have shown that folic acid does not reduce the risk of heart attacks or strokes. And with one exception, there’s no evidence to support the use of other supplements for your heart.
The one exception is fish oil supplements, which are a source of omega-3 fats. The American Heart Association recommends fish oil supplements to prevent heart disease-related deaths in people with coronary heart disease who are unable to consume 1,000 mg of fish oil a day from their diet alone. The organization also recommends fish oil supplements (2,000 to 4,000 mg per day) for people who need to reduce their triglyceride levels. Always consult your doctor before taking fish oil supplements, because they can cause excessive bleeding in some people.
