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Digestion lipids

People of western culture ingest about 100 g of triacylglycerol per day. The digestion and absorption of this lipid, together with the ingested phospholipids, depend on secretions from the pancreas (exocrine) and a flow of bile from the gall-bladder. The important constituents of the pancreatic secretions are enzymes, and those of the bile are the bile salts (Chap. 6). [Pg.362]

Lipid digestion is accomplished in the small intestine by the action of hydrolytic enzymes, called lipases and phospholipases, which act on dietary triacylglycerol and phospholipids, respectively. [Pg.362]

and R3 are the hydrocarbon chains of fatty acids. Ester bonds between a fatty acid and glycerol are hydrolyzed. In the lumen of the intestine, the complete action of pancreatic lipase on dietary triacylglycerol produces the following  [Pg.362]

R-i and R2 are the carbon chains of fatty acids, R4 is an alcohol. Only one ester bond between fatty acid and glycerol is hydrolyzed, specifically at position 2 of the glycerol carbon chain. [Pg.363]

Phospholipase Aj hydrolyzes the ester bond between a fatty acid and glycerol in position 1 of the carbon chain of a phosphoglyceride. [Pg.363]


Most pancreatic secretion takes place during the intestinal phase. The intestinal hormone secretin stimulates release of a large volume of pancreatic juice with a high concentration of bicarbonate ion. Secretin is released in response to acidic chyme in the duodenum (maximal release at pH < 3.0). The intestinal hormone cholecystokinin is released in response to the presence of the products of protein and lipid digestion. Cholecystokinin then stimulates the release of digestive enzymes from the pancreas. [Pg.298]

However, Patton and Carey (42) have suggested that calcium soap formation is a part of usual lipid digestion. Other research indicates that the availability of calcium from calcium soaps infused into rat intestines increases as fatty acid chain length decreases ans as degree of polyunsaturatedness increases (58). [Pg.179]

C. These products of lipid digestion combine to form mixed micelles, which are taken up efficiently by enterocytes. [Pg.103]

Singh, H., Ye, A., Horne, D.S. (2009). Structuring food emulsions in the gastrointestinal tract to modify lipid digestion. Progress in Lipid Research, 48, 92-100. [Pg.77]

Much of the cholesterol synthesis in vertebrates takes place in the liver. A small fraction of the cholesterol made there is incorporated into the membranes of he-patocytes, but most of it is exported in one of three forms biliary cholesterol, bile acids, or cholesteryl esters. Bile acids and their salts are relatively hydrophilic cholesterol derivatives that are synthesized in the liver and aid in lipid digestion (see Fig. 17-1). Cholesteryl esters are formed in the liver through the action of acyl-CoA-cholesterol acyl transferase (ACAT). This enzyme catalyzes the transfer of a fatty acid from coenzyme A to the hydroxyl group of cholesterol (Fig. 21-38), converting the cholesterol to a more hydrophobic form. Cholesteryl esters are transported in secreted lipoprotein particles to other tissues that use cholesterol, or they are stored in the liver. [Pg.820]

Digestion of dietary lipids Dietary lipids DIGESTION OF DIETARY LIPIDS (p. 171) Dietary lipids consist primarily of triacylglycerol, with some cholesterol, cholesteryl esters, phospholipids, and free (nonesterified) fatty acids. [Pg.483]

The products of lipid digestion—free fatty acids, 2-monoacylglycerol, and cholesterol—plus bile salts, form mixed micelles that are able to cross the unstirred water layer on the surface of the brush border membrane. Individual lipids enter the intestinal mucosal cell cytosol. [Pg.484]

Porter, C.J.H. et al. (2004) Useimfvitro lipid digestion data to explain tliB vivo performance of triglyceride-based oral lipid formulations of poorly water-soluble drugs studies with halofanttiifiSiarm. Sci.,... [Pg.252]

Boyd, B.J., Porter, C.J., and Charman, WN, Using the polymer partitioning method to probe the thermodynamic activity of poorly water-soluble drugs solubilized in model lipid digestion products,... [Pg.635]

These agents are administered to aid in the digestion of food. The primary digestant preparations contain pancreatic enzymes or bile salts. Pancreatic enzymes such as amylase, trypsin, and lipase are responsible for digestion of carbohydrates, proteins, and lipids, respectively. These enzymes are normally synthesized in the pancreas and secreted into the duodenum via the pancreatic duct. Bile salts are synthesized in the liver, stored in the gallbladder, and released into the duodenum via the common bile duct. Bile salts serve to emulsify lipids in the intestinal tract and are important in lipid digestion and absorption. [Pg.397]

Lipids, unlike many excipients, whether present in food or as discreet pharmaceutical additives, are processed both chemically and physically within the GIT before absorption and transport into the portal blood (or mesenteric lymph). Indeed, most of the effects mediated by formulation-based lipids or the lipid content of food are mediated by means of the products of lipid digestion—molecules that may exhibit very different physicochemical and physiological properties when compared with the initial excipient or food constituent. Therefore, although administered lipids have formulation properties in their own right, many of their effects are mediated by species that are produced after transformation or activation in the GIT. An understanding of the luminal and/or enterocyte-based processing pathways of lipids and lipid systems is therefore critical to the effective design of lipid-based delivery systems. [Pg.93]

Solubilization of lipid digestion products in intestinal mixed micelles enhances their dissolution and dramatically increases the GI lumen-enterocyte concentration gradient that drives absorption by means of passive diffusion. Micelles, however, are not absorbed intact [8, 9], and lipids are thought to be absorbed from a monomolecular intermicellar phase in equilibrium with the intestinal micellar phase [10], The dissociation of monomolecular lipid from the micellar phase appears to be stimulated by the presence of an acidic microclimate associated with the enterocyte surface [11,12], In addition to passive diffusion, growing evidence suggests that active uptake processes mediated by transport systems located in the enterocyte membrane are also involved in the absorption of (in particular) fatty acids into the enterocyte [4],... [Pg.94]

III. THE INTERACTION OF LIPOPHILIC DRUGS WITH THE LIPID DIGESTION/ABSORPTION CASCADE... [Pg.95]


See other pages where Digestion lipids is mentioned: [Pg.232]    [Pg.475]    [Pg.291]    [Pg.201]    [Pg.225]    [Pg.58]    [Pg.30]    [Pg.169]    [Pg.269]    [Pg.269]    [Pg.130]    [Pg.257]    [Pg.172]    [Pg.172]    [Pg.174]    [Pg.175]    [Pg.122]    [Pg.244]    [Pg.282]    [Pg.115]    [Pg.116]    [Pg.124]    [Pg.130]    [Pg.92]    [Pg.93]    [Pg.93]    [Pg.93]    [Pg.94]    [Pg.94]    [Pg.95]    [Pg.97]    [Pg.110]    [Pg.127]    [Pg.202]    [Pg.202]   
See also in sourсe #XX -- [ Pg.1513 ]

See also in sourсe #XX -- [ Pg.46 , Pg.342 ]

See also in sourсe #XX -- [ Pg.204 ]




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Colipase lipid digestion

Dietary lipids digestion

Digestion of dietary lipid

Digestion of lipids

Endoplasmic reticulum lipid digestion

Gastrointestinal tract lipid digestion

Lipid digestion bile acids

Lipid digestion disorders

Lipid digestion mixed micelles

Lipid digestion, absorption

Lipid-starch complexes digestibility

Lipids anaerobic digestion

Lipids digestion and

Lipids digestion and absorption

Micellar phase lipids during digestion

Micelles lipid digestion

Pancreatic lipase lipid digestion

Retinol lipid digestion

Stomach lipid digestion

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