Linoleic and linolenic acids are polyunsaturated fatty acids called essential fatty acids. You may obtain linoleic and linolenic acids from the fats in vegetables, nuts and seeds in your diet. Linoleic acid is called an omega-6 fatty acid, and linolenic acid is called an omega-3 fatty acid. In your body, linoleic acid is used for the production of another omega-6 fatty acid called arachidonic acid, and linolenic acid is used for the production of another omega-3 fatty acid called docosahexaenoic acid.
Essential Fatty Acids
Linoleic acid and linolenic acid are called essential fatty acids because they cannot be made in your body, and you must obtain them from your diet. Arachidonic acid and docosahexaenoic acid are also essential to your body, but they can be made from the linoleic acid and linolenic acid in your diet. Arachidonic acid is made in all of your tissues, but your liver produces most of your docosahexaenoic acid. Docosahexaenoic acid is transported from your liver to your brain and other tissues through your blood.
Conversion of linolenic acid to docosahexaenoic acid in the fetal and infant liver is insufficient to support nerve tissue development in the early stages of life. Therefore, maternal docosahexaenoic acid is transported across the placenta to the developing child, and docosahexaenoic acid is also present in breast milk. Docosahexaenoic acid is used in the formation of nerve tissue and the fatty layer that insulates nerve tissue. A docosahexaenoic acid deficiency during development can impair cognition and lead to behavioral problems in your growing child. For example, a deficiency of docosahexaenoic acid is associated with attention-deficit hyperactivity disorder in children.
Linoleic acid, linolenic acid, arachidonic acid and docosahexaenoic acid are stored in your tissue cells, where they can be released and converted into a very complex and diverse class of molecules called eicosanoids. The eicosanoids have regulatory control over many of your body’s activities, including immunity, blood clotting, nervous system function, reproduction and inflammation. In general, linoleic acid and arachidonic acid are converted to eicosanoids that promote the inflammation associated with pain, fever, arthritis, cardiovascular disease and infection. In contrast, linolenic acid and docosahexaenoic acid are converted to eicosanoids that tend to subdue the processes of inflammation.
Linoleic acid and arachidonic acid are omega-6 fatty acids, whereas linolenic acid and docosahexaenoic acid are omega-3 fatty acids. The two omega fatty acid sub-types are not interconvertible in your body. Try to balance the ratio of omega-6 to omega-3 fats in your diet. Striving to balance this ratio toward equality may lower your risk for developing many diseases associated with aging, including cardiovascular disease, Type 2 diabetes and cancer. Including a source of docosahexaenoic acid in your diet such as ocean seafood may slow cognitive decline and lower your risk of developing Alzheimer’s disease as you age.
- Lipids: Essential Fatty Acids in Visual and Brain Development
- The Proceedings of the Nutrition Society: Dietary Essential Fatty Acids and Brain Function -- A Developmental Perspective on Mechanisms
- Prostaglandins, Leukotrienes, and Essential Fatty Acids: Brain Metabolism of Nutritionally Essential Polyunsaturated Fatty Acids Depends on Both the Diet and the Liver
- Annals of the New York Academy of Sciences: Perinatal Supply and Metabolism of Long-Chain Polyunsaturated Fatty Acids -- Importance for the Early Development of the Nervous System
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- Nutrition Reviews: Nutrition in Brain Development and Aging -- Role of Essential Fatty Acids
- Molecular Neurobiology: Evolutionary Aspects of Diet -- The Omega-6/Omega-3 Ratio and the Brain
- Annual Review of Nutrition: Docosahexaenoic Acid Signalolipidomics in Nutrition -- Significance in Aging, Neuroinflammation, Macular Degeneration, Alzheimer’s, and Other Neurodegenerative Diseases
Michael Peluso is a semi-retired scientist in the field of nutritional biochemistry. He received his M.S. in nutrition from the University of California, Davis and Ph.D. in nutrition from the University of Missouri. Peluso's work has appeared in scholarly publications such as the "Journal of Nutrition," "Lipids" and "Experimental Biology and Medicine."