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.

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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 percent.

Dietary Fat and Cholesterol

The average American gets about 33 percent 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 percent 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 percent 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 percent 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.

Publication Review By: Roger S. Blumenthal, M.D. and Simeon Margolis, M.D., Ph.D.

Published: 10 Mar 2011

Last Modified: 15 Jan 2015