Good Sources Of Polyunsaturated Fat

Polyunsaturated fats contain more than one double bond in their structure. There are two types of polyunsaturated fat: omega-3 and omega-6. The omega-3 fatty acid alpha-linoleic acid and the omega-6 fatty acid linolenic acid are essential for good health and must be obtained from the diet. These fats are needed for a healthy brain, skin and bones, and they help to prevent heart disease and cancer.

Flaxseed

Flaxseeds and flaxseed oil are excellent sources of the omega-3 fatty acid ALA. The body can convert ALA into eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA, which have been linked with a decreased risk of heart disease. However, only 8 percent and 4 percent of ALA is converted into EPA and DHA respectively, with the conversion rates being slightly higher in females of reproductive age.

Fish

Cold-water oily fish are the best sources of EPA and DHA. Fish do not actually synthesize these fatty acids, but get them from eating algae or other fish. The American Heart Association recommends eating fish, particularly oily fish, at least twice a week. A serving is 3.5 ounce, cooked. Examples of oily fish include salmon, lake trout, sardines, mackerel, herring and albacore tuna.

Canola Oil

While the majority of fat in canola oil is monounsaturated, it does contain good quantities of both omega-3 and omega-6 fatty acids. Moreover it is very low in saturated fat. Because of this fat profile, canola oil can lower LDL, or bad, cholesterol and elevate HDL, or good, cholesterol.

Evening Primrose Oil

Evening primrose oil is a good source of the omega-6 fatty acid gamma-linolenic acid, GLA. Although most omega-6 fatty acids are pro-inflammatory, GLA is anti-inflammatory because it can inhibit the formation of compounds that cause inflammation. Evening primrose oil is also marketed as an aid for premenstrual syndrome, however, according to D. Budieri and colleagues in "Controlled Clinical Trials," well-conducted scientific studies have failed to show a positive effect.

Vegetable Oils

Most vegetable oils contain significant amount of omega-6 fatty acids. Excessive consumption of omega-6 fatty acids can be harmful to health. The ratio of intake of omega-6 to omega-3 is most important in maintaining a healthy consumption of polyunsaturated fat. A ratio larger than 10:1 is considered detrimental to health.