The hypothesis that intestinal GLUT5 or GLUT2 expres-
sion is reduced in fructose malabsorption was tested by
Wilder-Smith et al. in 11 adults with fructose malabsorp-
tion (positive breath test after ingestion of 35 g fructose in
combination with abdominal symptoms) and 15 control
subjects. The messenger RNA (mRNA) content and protein
expression of GLUT5 and GLUT2 was similar in both
groups [11].