Essential fatty acids are those that you must obtain from your diet because you cannot synthesize them in your body. There two essential fatty acids, alpha-linolenic acid, or ALA, and linoleic acid, or LA. ALA is an omega-3 fatty acid, and LA is an omega-6 fatty acid. These fatty acids are vital to proper human functioning, so it is important to consume adequate amounts of them in your diet.
Physiology
When you eat ALA or LA, your body uses them to synthesize longer chain fatty acids. The fatty acid ALA is converted into a long-chain omega-3 fatty acid called eicosapentaenoic acid, or EPA. LA is converted into a long-chain omega-3 fatty acid called docosahexaenoic acid, or DHA.
Functions
Fatty acids build a part of your cell membranes called phospholipids. These phospholipids come together to form a unique structure called the phospholipid bilayer, which allows the cell membrane to move and allow substances to move in and out of the cell wall.
Large amounts of DHA are found in the cells of your retina. The Linus Pauling Institute notes that DHA is required for the development and proper functioning of the retina. DHA also plays a role in maintaining proper brain function. If you do not have enough DHA in your brain, it can lead to cell alterations that cause learning difficulties.
A diet high in omega-3 and omega-6 fatty acids has also been linked to lower cholesterol levels and thus a lower risk of developing heart disease.
Recommendations
The Food and Nutrition Board provides recommendations for essential fatty acid intake as an adequate intake, or AI. Male adults between the ages of 19 and 50 should consume 17 grams of omega-6 fatty acids, whereas females of the same age should consume 12 g. Male adults over the age of 50 require 14 g per day, and women of the same age should consume 11 g daily. Male adults 19 and over should consume 1.6 g per day and female adults should consume 1.1 g daily.
The best sources of linoleic acid include safflower oil, sunflower seeds, sunflower oil, corn oil, soybean oil, pecans, Brazil nuts and sesame oil. The best sources of alpha-linolenic acid include flaxseed oil, ground flaxseeds, walnuts, walnut oil, canola oil, soybean oil, mustard oil and tofu.
Deficiency
If you do not consume adequate amounts of the essential fatty acids, it can lead to physical symptoms, such as skin rash, poor wound healing, increased susceptibility to infection and delayed growth in infants and children. An essential fatty acid deficiency usually occurs in those with fat malabsorption disorders or other chronic diseases, such as cystic fibrosis.
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