[Absorption of sugars in the small intestine]

Sugars cross the brush border membranes of small intestine by various routes: two Na+-dependent carriers for both free D-glucose and D-galactose (which, in the presence of a gradient in electrochemical potential of Na+, are accumulated against their own concentration gradient); one Na+-independent non-concentrative carrier for D-fructose; various minor disaccharidase-associated systems for the transport of some of the monosaccharides arising from the disaccharides.