Physiology

The physiology of the gastrointestinal absorption of (and the energy retrieved from) the glucose molecule along the length of the gastrointestinal tract in its various forms is discussed in the following sections, together with the influence of other dietary factors (Figure 2).

Absorption

In its simplest form, glucose ingested by mouth is rendered isotonic in the stomach by the gastric juices and expelled through the pylorus into the duodenum, where active transport takes place at the brush border by way of a sodium-linked glucose transporter. The absorbed glucose that is taken up by way of the portal vein suppresses hepatic glucose output but does not markedly alter the glucose balance across the liver. The major part of the absorbed glucose is taken up by muscle and also adipose tissue under the action of insulin. Similarly, sucrose, maltose, and lactose are both split and absorbed at the brush border by the brush border enzymes sucrase-isomaltase, maltase, and lactase. Although sucrose deficiency is exceedingly rare, hypolactasia is common in adult life in most of the world's populations, with the exception of those of northern European origin. Thus, unlike sucrose malabsorption, small-intestinal lactose malabsorption is common, with significant amounts of lactose entering

Glucose, maltose dextrins and amylopectin

High amylose starch (RS2) Retrograded starches (RS3)

'Entrapped starch' (RS1)

Intact granules (Soluble fiber, antinutrients, enzyme inhibitors)

Stomach

Stomach

Small intestine

Colon

High amylose starch (RS2) Retrograded starches (RS3)

'Entrapped starch' (RS1)

Intact granules (Soluble fiber, antinutrients, enzyme inhibitors)

Glucose
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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