Sugar transporters fructose

Other monosaccharides are absorbed by carrier-mediated diffusion there are at least three distinct carrier proteins one for fructose, one for other monosaccharides and one for sugar alcohols. Because they are not actively transported, fructose and sugar alcohols are absorbed only to a limited extent, and after a moderately high intake a significant amount will avoid absorption and remain in the intestinal lumen, acting as a substrate for colon bacteria and, like unabsorbed disaccharides in people with disaccharidase deficiency, causing abdominal pain and diarrhoea. 

White, L.W. andB.R. Landau, 1965 Sugar transport and fructose metabolism in human intestine vitro. J Clin Invest 44, 1200-1213. 

Sugar The hydrolysis of sucrose in the intestine produces both glucose and fructose, which are transported across the epithelial cells by specific carrier proteins. The fructose is taken up solely by the liver. Fructose is metabolised in the liver to the triose phosphates, dihydroxy-acetone and glycer-aldehyde phosphates. These can be converted either to glucose or to acetyl-CoA for lipid synthesis. In addition, they can be converted to glycerol 3-phosphate which is required for, and stimulates, esterification of fatty acids. The resulting triacylglycerol is incorporated into the VLDL which is then secreted. In this way, fructose increases the blood level of VLDL (Chapter 11). 

---