Linolenic nutritional role

Linoleic acid can not be synthesized by the human body. This acid and other members of the tu6 family are considered as essential fatty acids required as building blocks for biologically active membranes. a-Linolenic acid, which belongs to the tu3 family and which is synthesized only by plants, also plays a nutritional role as an essential fatty acid. 

Y. S. Huang and D. E. Mills, eds., y-Linolenic Acid Metabolism and its Roles in Nutrition and Medicine, American Oil Chemists Society, Champaign, Illinois, 1996. 

Karlstad MD, Palombo JD, Murray MJ, Demichele SJ. 1996. The antiinflammatory role of y-linolenic and eicosapen-taenoic acids in acute lung injury. In y-Linolenic Acid Metabolism and Its Roles in Nutrition andMedicine, ed. YS Huang, DE Mills, pp. 137-67. Champaign AOCS... 

Phillips. J.C.. and Huang, Y.-S. (1996) Natural Sources and Biosynthesis of y-Linolenic Acid An Overview, in y-Linolenic Acid Metabolism and Its Roles in Nutrition and Medicine (Huang,Y.-S., and Mills, D.E., eds.) pp. 1-13, AOCS Press, Champaign, IL. 

F.D. Gunstone, Gamma linolenic acid — occurrence and physical and chemical properties. Progress in Lipid Research, 1992, 31, 145-161. D.F. Horrobin, Nutritional and medical importance of gamma-linolenic acid, Progress in Lipid Research, 1992, 31, 163-194. y-Linolenic Acid — Metabolism and its Roles in Nutrition and Medicine, Y.-S. Huang and D.E. Mills (eds), AOCS Press, Champaign, Illinois (1995). 

The human body is capable of synthesizing some fatty acids from carbohydrates or other fatty acids. However, humans cannot synthesize sufficient amounts of polyunsaturated fatty acids such as linoleic acid, linolenic acid, and arachidonic acid. Because they must be obtained from the diet, they are known as essential fatty acids. In infants, a deficiency of essential fatty acids can cause skin dermatitis. However, the role of fatty acids in adult nutrition is not well understood. Adults do not usually have a deficiency of essential fatty acids. 

In section 3.2.4 we described the biosynthesis of the polyunsaturated fatty acids and indicated that animals lack the A12 and A15-desaturases. They cannot, therefore, synthesize linoleic or linolenic acids. It turns out, however, that these polyunsaturated fatty acids are absolutely necessary for the maintenance of growth, reproduction and good health and must, therefore, be obtained in the diet from plant foods. They are called essential fatty acids and their role in nutrition and health will be described in detail in section 5.2.2. Chapter 5 will also describe the dual roles of the essential fatty acids and their longer-chain, more highly unsaturated metabolic products in membranes and as precursors of a variety of oxygenated fatty acids with potent biological activities now generally known collectively as the eicosanoids. 

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