Dietary Fats on Phospholipids in the Body

Dietary triglycerides (TGs) are packaged into chylomicrons in the enterocyte and delivered to the circulatory system via the thoracic duct. Normally the lacteals and thoracic duct contain a clear, yellowish fluid. After a fabcontaining meal, however, they are filled with an opaque white liquid that contains chylomicrons laden with TGs. Arise in the plasma concentration of chylomicrons can be detected after a meal of fat or oil by assays for particulate matter or for one constituent of the chylomicrons, the TGs, The rise in chylomicron concentration usually is followed by a fall to very low basal concentrations. However, defects in the mechanisms that facilitate this decline are revealed when the levels of particulate matter or of plasma TGs remain elevated. These defects, which can present a serious health risk, are illustrated by data from patients suffering from hypertriglyceridemia. (The prefix hyper means higher than normal hypo means lower than normal.) 

The nature of a fatty add influences its fate. Short- and medium-tdiain fatty adds tend to be oxidised immediately to carbon dioxide, rather than deposited as TGs or phospholipids. The presence of double bonds ( unsaturations ) in long-chain fatty adds influences the immediate fate of the add. Some evidence suggests that unsaturated fatty acids, such as 18 2, tend to be oxidized at a slightly faster rate in the hours following a meal than saturated fatty acids, such as 18 0 (Jones et al., 1985, Jones and Schoeller, 1988). More specifically, about 2% of a test meal of 18 0 may be oxidized in the 9 hours toUowing Ingestion, whereas about 10% of a test meal of 18 2 may be oxidized in the same period, The mechanisms that influence the fates of unsahirated and saturated fatty adds are only beginning to be understood. 

The nature of the fatty adds in the TGs stored in adipose tissue and those in the phospholipids in membranes can be influenced by the diet, The rat study reported in Table 6.3 assessed the plasma membranes of the liver. Diets containing 10% oil or fat by weight were fed to young and rapidly growing rats. Rapidly growing 

Fatty add Diet conlienMlCl% iipid). viembratte fatly acid content  

Several observations can be made- One of the major fatty acids of butler is 14 0. Obviously, this fatty add was not incorporated into the phospholipids of the membrane. Fatty acids with 14 carbons were essentially absent from the membranes, The food lipids did not contain Song-chain fatty acids of 20 or 22 carbons however, the membranes contained substantial amounts of these acids. For example, about 20% of ihe fatty add content of the membranes of the com oil-fed rat was 20 4, 

Fatty add Diet content (10% Upid) Membrane fatty add content  

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Influence of Dietary Fats on Phospholipids in the Body Sphingosine-Based Lipids Covalent Binding of Lipids to Proteins Cholesterol Lipoproteins... 

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