Essential fatty acids, or EFAs, are those that the body needs to maintain health but cannot manufacture on its own. There are two classes of EFAs, including omega-3 fatty acids and omega-6 fatty acids. The body also needs omega-9 fatty acids, although this acid is not essential because the body produces small amounts of it. You can find EFAs in a number of plant and animal sources, and the Institute of Medicine includes dietary reference intakes for each.
Omega-3 Fatty Acids
Omega-3 fatty acids consist primarily of alpha linolenic acid, which the body breaks down and converts into other acids that aid in organ and cellular function. Omega-3 fatty acids are a key structural component of cellular walls and help optimize the cell's blood and oxygen circulation. Their effects on cell structure and circulation have been demonstrated to reduce unhealthy cholesterol in the bloodstream, reduce inflammation and reduce cardiovascular risk. According to the DHA-EPA Omega-3 institute, an increasing body of research has shown that docosahexaenoic acid, another omega-3 fatty acid, has a positive effect on brain and nervous system function as well.
Omega-6 Fatty Acids
Omega-6 fatty acids, or linoleic acid, also serve a number of positive functions in the human body. Omega-6 fatty acids promote skin and hair growth, bone health, energy metabolism and reproductive health. Healthy bodies will convert omega-6 fatty acids into gamma linoleic acid, which the body needs to control inflammation and maintain immune system health. However, diets high in sugar, alcohol and trans fats, and lifestyle factors such as aging and smoking, can prevent this process. Some people may then need to consume a gamma-linoleic acid supplement.
Daily Requirements
It is important to balance omega-3 fatty acids in your body with omega-6 fatty acids, as too much of the latter tends to promote inflammation. The typical American diet includes 14 to 25 times the omega-6 than omega-3 fatty acids, however. About 5 to 10 percent of your total calories should come from omega-6 fatty acids, while omega-3 fatty acids should account for 0.6 to 1.2 percent, according to the Institute of Medicine. Adult males should generally consume about 17 g of omega-6 fatty acids per day, while adult females need about 12. Adult males need about 1.6 g of omega-3 fatty acids, while adult females should consume 1.1 g.
Sources
The best dietary sources of EFAs are fish, nuts and plant oils. Cold-water fish such as salmon, tuna and halibut tend to be higher in EFAs than warm-water fish, while flaxseeds and flaxseed oil, canola oil, pumpkin seeds and pumpkin oil, and walnuts and walnut oil tend to be the highest plant-based sources. You can also take omega-3 and omega-6 fatty acid supplements to help meet your daily needs.
References
- University of Maryland Medical Center: Omega-3 Fatty Acids; June 2009
- University of Maryland Medical Center: Omega-6 Fatty Acids; June 2009
- Institute of Medicine; Dietary Reference Intakes; Macronutrients; 2005
- Linus Pauling Institute at Oregon State University: Essential Fatty Acids; Jane Higdon; December 2005
- DHA-EPA Omega 3 Institute: Differentiation of ALA (Plant Sources) from DHA+EPA (Marine Sources)...
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