How Fish and Fish Oils Lower Cholesterol

A group of Eskimos in Greenland provided the first indication that fish and fish oils could play a beneficial role in controlling cholesterol and preventing coronary heart disease. It seems that although these Eskimos consumed a diet rich in fat, they had low blood-cholesterol levels and rarely suffered from heart disease. Closer scrutiny of the Eskimo diet uncovered fish as the source of most of the fat.

The fat in these fish, however, was different from the fat found in other animals. It was rich in two polyunsaturated fatty acids, docosahexanoic acid (DHA) and eicosapentaenoic acid (EPA). These omega-3 fatty acids, as they are called, are found in marine vegetation called phytoplankton. Fish obtain these fatty acids by feeding on phytoplankton and then storing them in their own body fat.

Depending upon where they feed and how much fat they store, fish have different amounts of these fatty acids; therefore some fish are better than others as sources of omega-3 fatty acids. Salmon, mackerel, sardines, herring, anchovies, albacore tuna, and lake trout are some of the richest sources. Some eggs, margarine, pasta, milk, and meat are now enriched with omega-3 fatty acids as well.

The omega-3 fatty acids, DHA and EPA, in fish are thought to prevent irregular heartbeat (arrhythmia), reduce inflammation and the risk of blood clots, decrease high triglyceride levels and blood pressure, and modestly improve HDL cholesterol. Fish may also help lower LDL cholesterol when substituted for foods that are high in saturated fat, such as meat. However, some of the benefits of fish can be lost when cooked improperly. Steer clear of fried and breaded fish and frozen fish sticks, which can be high in saturated fat and trans fat. Also, cooking fish in butter or lard decreases the nutritional value by adding saturated fat and cholesterol. The best way to cook fish is broiling or baking it.

While it's true that there are trace amounts of mercury in nearly all fish, it is usually not a health concern for most people. The Food and Drug Administration and the Environmental Protection Agency, however, advise that young children, nursing mothers, and women who may become or who are pregnant should not eat shark, swordfish, king mackerel, or tilefish because they are higher in mercury than other fish. They should also eat no more than six ounces of canned albacore, or solid white, tuna each week; canned albacore tuna has a higher mercury content that canned light tuna. In addition, it is recommended that these groups of people limit their consumption of locally caught fish to six ounces per week unless local government safety guidelines direct otherwise.

Polychlorinated biphenyls (PCBs) are environmental toxins found in salmon. Because PCBs accumulate in fat, removing the skin and cooking the fish so that the fat can drip off reduces the amount of PCBs in the salmon. Wild and canned salmon are lower in PCBs than farmed Atlantic salmon. (Most Atlantic salmon sold in the United States is farmed.) However, the best way to minimize your exposure to toxins is to vary your selection of fish.

The American Heart Association recommends that people who have or are at high risk of cardiovascular disease, and even those who are healthy, should eat a variety of fish at least twice a week. But what if you don't like eating fish? Talk with your doctor about taking a fish-oil supplement. People with heart disease should consume 1 g of DHA and EPA daily from fish, supplements, or a combination. And those with high blood triglycerides should take 2 to 4 g of DHA and EPA daily from supplements; any amount over 3 g should be taken under a doctor's care, as high amounts of omega-3 fatty acids can cause internal bleeding in some people.

Many supplements claim to contain one gram of fish oil, but it can vary. Total how much EPA and DHA are present in the supplement to determine how much omega-3 fatty acid the supplement actually contains. High potency pills contain 800 to 900 mg of EPA and DHA. The most concentrated pills are available by prescription only. To avoid a fishy aftertaste, keep the fish oil supplements in the refrigerator. Omega-3 fatty acids should not be used to lower LDL cholesterol; in fact, they may slightly raise LDL cholesterol.

Unlike fish oil, which can have an unpleasant aftertaste, garlic is a delicious way to not only spice up foods, but also to help lower cholesterol. See the next page for more information about the benefits of garlic.