Digestion and absorption of carbohydrates, proteins and fats
5 min read
Definition
Digestion breaks foodstuff into smaller, absorbable particles; absorption transports digestion products, vitamins, minerals and water into blood and lymph.
Digestion and Absorption of Carbohydrates
Starch, the main polysaccharide digested, is hydrolyzed by salivary and pancreatic amylase to maltose, maltotriose and α-dextrins.
Brush border oligosaccharidases complete carbohydrate digestion to the absorbable monosaccharides glucose, galactose and fructose.
Absorption is maximal in duodenum/jejunum, decreasing toward ileum.
Glucose and galactose enter enterocytes via SGLT1 (Na+-dependent secondary active transport); fructose via GLUT5 (facilitated diffusion).
All three exit the enterocyte into blood via GLUT2.