Fish Oil Health Article

Description

Fish oils are derived from such cold-water fish as salmon, cod, tuna, or mackerel. They have recently acquired a new visibility as dietary supplements because they are high in omega-3 fatty acids. Omega-3 fatty acids, together with the omega-6 fatty acids, are important components of a healthful diet. The body cannot manufacture them, therefore they must be obtained from grains, fruits, vegetable oils, and other foods. In addition, people should consume a balanced ratio of omega-6 and omega-3 fatty acids. Some researchers believe that these two types of fatty acids should be consumed in a 1:1 ratio, while others maintain that people should obtain several times more omega-3 than omega-6 fatty acids from their diet. In either case, the fact that fish oils are high in omega-3 fatty acids may help people to maintain a good balance between the two types of fatty acids. The most important types of omega-3 fatty acids found in fish oils are eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA). The body needs EPA to produce prostaglandins, which are hormone-like substances that help to protect the heart and the cell membranes. DHA is required for the normal development of the brain, the eyes, and the reproductive system.

General use

In general, fish oils are recommended as dietary supplements to lower the levels of triglycerides in the blood, counteract inflammation in various parts of the body, and thin the blood.

Heart disease and stroke

The omega-3 fatty acids in fish oils increase the concentrations of good cholesterol (high density lipoproteins, HDL) in the blood while decreasing the concentrations of bad cholesterol (triglycerides). They also lower the total cholesterol level. Furthermore, these omega-3 oils protect the heart by preventing the formation of blood clots and fatty deposits (plaque) on the arterial walls. In people with coronary heart disease, fish oils may help to reduce the risk of blood clots in the brain or in the lungs; pain associated with angina; and the risk of cardiac arrythmias.

The benefits of omega-3 fatty acids have been shown in clinical studies. Investigation of the possible benefits of fish oils began when researchers discovered that Eskimos rarely suffer from heart attacks or rheumatoid arthritis (RA) even though their diet is high in fat from fish, seals, and whales. Because these sources of fat have a high omega-3 fatty acid content, it was assumed that the type of fatty acid that they contained helped to protect the Eskimos from the usual consequences of high-fat diets. Later studies confirmed that diets high in omega-3 fatty acids decrease the risk of heart attacks, strokes, and abnormal heart rhythms. In one study of 20,551 doctors, those who ate at least one fish meal per week cut their risk of heart attacks in half compared to those who ate fish once a month or less. In the five-year Lyon study, men who followed a Mediterranean diet with emphasis on omega-3-rich oils, fish, fruits, and vegetables had their heart attack rates reduced by 70% compared to subjects in the control group. One question, however, is whether fish oil used by itself as a dietary supplement is as effective as a diet high in fish, since the two are not the same. One open trial of 11,324 people who were followed for three to five years found that fish oil did reduce the risk of death from heart attack. This study, however, was not a double-blind study, and its results cannot be taken as conclusive.

High blood pressure

Fish oils may help to control high blood pressure. Several studies have shown that taking fish oil can lower blood pressure. On the other hand, a 1997 study involving 2,000 subjects found no significant effect.

Rheumatoid arthritis

Fish oil may be useful in managing the symptoms of early rheumatoid arthritis (RA). A significant reduction in joint tenderness, morning stiffness, and fatigue, coupled with an increase in grip strength, has been observed in patients taking fish oil capsules. Fish oil appears to reduce the symptoms of RA without side effects, and to increase the effectiveness of standard medications for it. Fish oil does not, however, appear to slow the progress of RA.

Asthma

It has been claimed that fish oils reduce inflammation of the airways and may prevent asthma attacks. According to one author, allergic disorders such as asthma may be triggered by too much omega-6 and too little omega-3 fats in the diet. Two studies undertaken in 1994 and 1996 respectively, however, found no benefits from using fish oil in the management of asthma.