Fructose malabsorption in a child with chronic diarrhea

Fructose absorption in humans has been poorly understood compared to that of glucose and galactose. D-fructose has been shown to be absorbed at a slower rate than galactose and glucose but more efficiently than passively transported sugars. An active carrier-mediated mechanism for fructose transport has been found in the rat small intestine. The understanding of fructose transport in humans has advanced in recent years, as it has been suggested that the absorption capacity of fructose is limited in healthy adults and that glucose may stimulate fructose absorption in those subjects. Support for this hypothesis was provided when fructose/glucose cotransport was recently demonstrated in the rat. In the present paper we describe a 4-year-old boy with primary fructose malabsorption, which probably caused chronic diarrhea and failure to thrive