Author
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Lichtenstein, Alice |
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JONES, PETER - MCGILL UNIVERSITY |
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Submitted to: Present Knowledge in Nutrition Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 4/6/2005 Publication Date: 9/1/2005 Citation: Lichtenstein, A.H., Jones, P.J. 2005. Lipids: Absorption and transport. In: Ziegler, E.E., Filer, Jr., L.J., Filer, L.J. Present Knowledge in Nutrition. 9th Edition. Washington, DC: International Life Sciences Institute-Nutrition Foundation. p. 111-124. Interpretive Summary: Technical Abstract: Due to the hydrophobic nature of lipids, dietary fat is handled differently than protein or carbohydrate with respect with digestion and absorption. Dietary fats are broken down throughout the gastrointestinal system. A unique group of enzymes and cofactors allows this process to proceed in an efficient manner. Elegant systems operate to digest lipid, ferry it from the gastrointestinal tract through the unstirred water layer into the enterocyte. Within the enterocyte, complex lipids are resynthezied and packaged into lipoprotein particles for release into the lymph system for subsequent metabolism by peripheral tissue. Once in the body, the apolar nature of lipids necessitates multiple complex transport systems that are unique relative to protein and carbohdyrate. By the coordination of a number of plasma factors, cell surface receptors and intracellular trafficking of dietary lipid, via plasma lipoproteins, are ultimately delivered to target tissues. Agents that replace dietary fat or block absorption may possess utility in producing a negative energy balance consistent with risk reduction for obesity. Further work is needed to ascertain whether these approaches work over the very long term and what consequences, if any, are associated with prolonged usage. Similarly, agents that prevent the absorption of cholesterol possess utility in the management of individuals with elevated LDL cholesterol levels. |
