Low-density lipoprotein, or LDL, is a compound that contains cholesterol bound to protein. LDL circulates in the blood, along with other lipoproteins such as high density lipoprotein, or HDL. The body needs cholesterol for essential processes, including maintenance of cell membranes, production of hormones and many biochemical reactions. When blood cholesterol is too high, this raises the risk of serious disorders, including heart disease and stroke. Diet is important for regulating blood cholesterol levels, and consumption of omega-3 fish oils may help keep blood cholesterol at a healthy level.
LDL and HDL
LDL is called "bad" cholesterol because high levels in the blood raise the risk of cardiovascular disease. LDL can build up in the lining of blood vessels, forming deposits called plaque. When plaque is extensive, it narrows the diameter of blood vessels, making them more rigid and slowing or blocking the flow of blood. This is especially bad for the heart, which depends on adequate circulation through the coronary arteries. HDL is called "good" cholesterol because it carries cholesterol to the liver, where it is removed from the body. When cholesterol is removed by the liver, blood cholesterol levels fall. The American Heart Association indicates that high HDL and low LDL protect against a heart attack.
Fish Oil
Fish is a healthy food because it is high in protein and low in saturated fat. Certain fatty fishes are also excellent sources of omega-3 fatty acids, a type of fat that is very healthy for the heart. Omega-3 fatty acids raise HDL levels in the blood and lower the level of triglycerides, another type of unhealthy fat. As HDL levels rise, LDL tends to fall and plaque is gradually removed from the walls of blood vessels. Fish rich in omega-3 fatty acids include salmon, mackerel, herring, trout, sardines and albacore tuna.
Recommendations
The American Heart Association indicates that adults should consume fatty fish at least twice each week. A serving of fish is about 3.5 oz. of cooked fish, or about 3/4 cup of flaked fish. It also recommends grilling or baking fish, or frying it in healthy oil such as olive or canola oils. The Association says obtaining omega-3 fatty acids from fresh fish is best, but that canned fish may be substituted if necessary. It also indicates that taking fish oil supplements may be a good strategy for some people.
Fish Oil Supplements
Purified omega-3 fatty acids prepared from fish are available in capsule form at grocery and health food stores. These supplements may be helpful for people unable to cook fresh fish. The American Heart Association also says patients who already have coronary artery disease may benefit by increasing their intake of omega-3 fatty acids through supplements. It suggests that these patients consume at least 1g, or 1,000 mg, of fish oil daily, with a maximum daily dose of 3g, or 3,000 mg. Consult a doctor to determine if adding fish oil supplements is appropriate for you.
Precautions
Mercury and other toxins may contaminate some fresh fish. Those with the highest potential for mercury contamination are shark, swordfish, king mackerel and tilefish. For all fish, the possibility of exposure to toxins is reduced if the skin and surface fat is removed before cooking. Fish oil supplements are generally considered safe. However, they might cause a fishy aftertaste and might produce gas, nausea or diarrhea in some people. They may also interact with some medications, especially blood-thinners. If you take prescription drugs, discuss fish oil supplements with your doctor before adding them to your regimen.
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