Escape Digestion

Lactose, the primary sugar found in milk, is a disaccharide composed of glucose and galactose. With age, many children lose their ability to digest large amounts of lactose, leading to lactose intolerance. This permanent condition, which occurs in adolescence and adulthood, is not an important health concern, although it may lead to an aversion to milk, an important food. 

The enzyme lactase catalyzes the hydrolysis of lactose in the lumen of the gut. Generally, intestinal lactase activity occurs at a maximal level from birth through early childhood. Then activity declines to a residual level of 5 10% by the age of. 3 or later in most populations of the world. In persons of European descent, lactase activity can remain at a high level throughout adulthood. Low levels of lactase 

An interesting phenomenon is seen in (he far reaches of the northern hemisphere, where sucrose intolerance occurs among Eskimos. About 10% of the native population of Greenland is sucrose intolerant. The occurrence of sucrose intolerance among these populations is eonsi.stent with the lack of availability of sucrose-containing staples. People in Greenland traditionally have consumed meat as the major food source, and not fruits or sugar cane. 

De ise atesiforladoseintol erance thatinvolvesthe mea su remeiit of plasm a glucose levels. 

Fatty foods may prolong the gastric emptying time. How might the consumption of fat with milk affect lactose intolerance  

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Any starch escaping digestion in the upper gastrointestinal tract also contributes to dietary liber effects. Some food starches, and the amylosc... 

The lysosomal enzymes The lysosomes are membrane vesicles ubiquitous to mammalian cells and contain a panoply of hydrolytic enzymes, estimated to be over 60 in number, that function to digest practically any biological macromolecule. They are important to the discussion of oral macromolecular drug delivery for two reasons. First, any macromolecules that escape digestion by the pancreatic and brush border enzymes are likely to be taken up into the epithelial cells by the process of endocytosis. In this process, the apical membrane invaginates and the target molecules enter endocytic vesicles that then fuse with the lysosomes and are subjected to intracellular hydrolysis by the lysosomal enzymes. Second, the sloughing-off of the epithelial cells means that the lysosomal enzymes will be released into the lumen of the intestine. They may be... 

Ehetary proteins may escape digestion in the mildly acidic stomach of the human newborn. After feeding, the pH of the infant s stomach may remain near neutral or drop to only pH 4.0, in contrast with the pH of 2.0 reached in children and adults after eating. The output of pepsin, the protease of the stomach, also may remain low for the first several months of life. Consequently, proteins may escape acid denaturation and proteolysis in the shtmach of the newborn. Therefore, proteolysis by pancreatic proteases assumes increased importance. 

Carbohydrates that Escape Digestion 139 TABLE 3.1 Change of Starch and Sugar Content of Bananas during Ripening... 

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