Review Article CELL MEMBRANE FATTY ACIDS AND HEALTH JIHAN SEID HUSSEIN * Medical Biochemistry Department, National Research Center, Doki, Giza, Egypt. Email: jihan_husein@yahoo.com. Received: 08 Jun 2013, Revised and Accepted: 12 July 2013 ABSTRACT All living cells, prokaryotic and eukaryotic, have a plasma membrane that encloses their contents and serves as a semi-porous barrier to the outside environment. The basic matrix of the plasma membrane consists essentially of two sheets (a bilayer) of phospholipids molecules. Among the significant components of cell membranes are the phospholipids, which contain fatty acids. The types of fatty acids in the diet determine the types of fatty acids that are available to the composition of cell membranes. The cell membrane that contains phospholipids made from saturated fatty acids has a different structure and is less fluid than the one that incorporates essential fatty acids. Fatty acids carry out many functions that are necessary for normal physiological health. Saturated fatty acids are non-essential fatty acids and are harmful if ingested excessively in food. On the contrary, polyunsaturated fatty acids (PUFA) are designated as “essential” for good health as their metabolic precursors cannot be synt hesized in the body and must be ingested by food intake. Increased dietary intake of omega-6 leads to production of prostaglandins, thromboxanes and leukotrienes and interferes with the incorporation of omega-3 in cell membrane phospholipids.Omega-3 has the most potent anti-inflammatory effects. Inflammation is at the base of many chronic diseases, including coronary heart disease, diabetes, arthritis, cancer and mental health. Dietary intake of omega-3 fatty acids may prevent the development of many diseases. INTRODUCTION Our diet contains a complex mixture of fats and oils whose basic structural components are fatty acids. We generally consume at least 20 different types of fatty acids, which are classified as saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Fatty acids have many fates in the body, including β- oxidation for energy, storage in depot fat or incorporation into phospholipids, which form the major structural components of all cellular membranes [1]. Fatty acids carry out many functions that are necessary for normal physiological health. Saturated fatty acids are non essential fatty acids and are harmful if ingested excessively in food. On the contrary, polyunsaturated fatty acids (PUFA) are designated as “essential” for good health as their metabolic precursors cannot be synthesized in the body and must be ingested by food intake. PUFA have important effects on the structure and physical properties of localised membrane domains. They modulate enzyme activities, carriers and membrane receptors (low density lipoprotein LDL receptors, insulin, antibodies neurotransmitters, drugs receptors, etc.) [2]. Endogenous fatty acids deficiency in cells leads to changes of phospholipids fatty acid composition and physicochemical properties of plasma membrane and lowering their fluidity [3]. Thus, it is from interest to study the reflection of dietary fat on the cell membrane and the role of cell membrane component especially fatty acids in improving health. Cell membrane All living cells, prokaryotic and eukaryotic, have a plasma membrane that encloses their contents and serves as a semi-porous barrier to the outside environment. The membrane acts as a boundary, holding the cell constituents together and keeping other substances from entering. The plasma membrane is permeable to specific molecules, however, and allows nutrients and other essential elements to enter the cell and waste materials to leave the cell. Small molecules, such as oxygen, carbon dioxide, and water, are able to pass freely across the membrane, but the passage of larger molecules, such as amino acids and sugars, is carefully regulated [4]. Cell membrane structure The basic matrix of the plasma membrane consists essentially of two sheets (a bilayer) of phospholipids molecules (Figure 1). The phospholipids are amphoteric molecules (i.e. one end of the molecule is hydrophilic or water soluble and the other end is hydrophobic or water insoluble). Therefore, in an aqueous environment the two sheets adopt a phospholipids bilayer, with the hydrophobic ends of the molecules on the inside of the bilayer and the hydrophilic ends on the outside. Within this "sea" of phospholipids are embedded many different types of protein molecules, which have many specialist functions [5]. Cell membrane bilayer is composed of 40% lipids and glycolipids, and 60% integral proteins and glycoproteins. The lipids in the membrane bilayer are composed of phospholipids (75% to 88%), glycosphyngolipids (2% to 5%) and cholesterol (10% to 20%).The phospholipids include phosphatidylcholine (45% to 55%), phosphatidylethanolamine (15% to 25%), phosphatidylinositol (10% to 15%), phosphatidylserine (2% to 10%), phosphatidic acid (1% to 2%), sphyngomyelin (5% to 10%) and cardiolipin (2% to 5%) [6]. Fig. 1: Cell membrane structure [4] Cell membrane proteins The numerous types of protein molecule associated with plasma membrane can be broadly classified as extrinsic (peripheral) or intrinsic (integral) (Figure 2). Intrinsic proteins include receptors that span the width of the membrane; extrinsic protein includes various enzymes involved in mediating the intracellular effects of receptor activation by signaling molecules. Functionally, the membrane proteins can be divided into several distinct groups:  Receptors-respond to the binding of specific signaling molecules.  Ion channels-permit the passage of specific ions  Transporters- carry important ions or molecules across the membrane, sometimes against a concentration gradient. International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 5, Suppl 3, 2013 A A c c a a d d e e m mi i c c S S c c i i e e n n c c e e s s