Essential fatty acids are those which the body cannot produce on its own. Two classes of essential fatty acids exist, including alpha-linolenic acid, or omega-3, and linoleic acid, or omega-6. You need to obtain these fatty acids through dietary sources and, in 2002, the Food and Nutrition Board of the Institute of Medicine first provided adequate intake values for essential fatty acids, as well as acceptable macronutrient distribution ranges. You should generally consume about two to four times the amount of omega-6 fatty acids as you do omega-3.
Omega-3
The acceptable macronutrient distribution ranges for omega-3 fatty acids for adults is 0.6 to 1.2 percent of your total calories. If you consume an average diet of 2,000 calories each day, the maximum amount of omega-3 you should aim to consume is about 24 calories, or 2.4 g. While there is insufficient evidence to support a recommended dietary allowance for omega-3, the Institute of Medicine provides an adequate intake value for this fatty acid, or an amount believed to meet the nutritional needs of at least 97 to 98 percent of the people in each population. The adequate intake value for adult men is 1.6 g each day, and 1.1 g a day for adult women.
Omega-6
Omega-6 fatty acid requirements are much larger than those of omega-3. The acceptable macronutrient distribution ranges for omega-6 fatty acids is 5 to 10 percent of your total calories. If you consume a 2,000-calorie diet, the maximum amount of omega-6 you should consume is about 200 calories, or 22 g. The adequate intake value for adult females ages 19 to 30 is 12 g, while older women should consume about 11 . The adequate intake value for men between the ages of 19 and 30 is 17 g, while older men need about 14 g each day.
Excess Fatty Acids
The Institute of Medicine reports that there is no defined level at which excess essential fatty acid intake will lead to adverse health effects. The Institute of Medicine's upper limit values are based on obtaining an appropriate balance with the other fats and macronutrients. Some evidence suggests that exorbitant intake of polyunsaturated fat intake, such as omega-3 and omega-6 fatty acids, may lead to lipid peroxidation, which can contribute to atherosclerosis. The exact amount at which this may occur is not clearly defined.
EFA Sources
You can find essential fatty acids in both plant and animal products, as well as supplements. The highest dietary sources of omega-6 fatty acids include safflower oil, sunflower seeds and oil, pine nuts and a variety of other vegetable oils and seeds. Foods with a substantial amount of omega-3 fatty acids include vegetable oils, fish oils, fish and seafood products and, to a lesser extent, meat and eggs. Omega-6 supplements are generally extracted from plant oils, while omega-3 supplements usually come from flaxseed oil, algal and fungal sources or fish oils. Essential fatty acids supplements can be effective in meeting your nutritional needs and are best taken with meals. Avoid consuming more than 3 g of omega-3 or 3,000 mg of gamma-linolenic acid, a specific type of omega-6 a day in capsule form due to increased likelihood of internal bleeding and inflammation.
References
- Institute of Medicine; Dietary Reference Intakes; Macronutrients; 2005
- Linus Pauling Institute at Oregon State University; Essential Fatty Acids; Jane Higdon; December 2005
- University of Maryland Medical Center; Omega-3 Fatty Acids; June 2009
- University of Maryland Medical Center; Omega-6 Fatty Acids; June 2009
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