Background: Reduced nutrient absorption may contribute to malnourishment in the elderly. Age and diet modulate fructose uptake in mice. Alterations in fructose uptake may be paralleled by changes in the abundance of fructose transporters. Aims: The objectives were to determine 1) the effects of aging on fructose absorption in rats; 2) the effect of feeding diets enriched with saturated fatty acids (SFA), versus polyunsaturated fatty acids (PUFA); and 3) the mechanisms of these age-and diet-associated changes. Methods: Male Fischer 344 rats aged 1, 9 and 24 months received isocaloric diets enriched with SFA or PUFA. The uptake of ¹⁴C-labelled D-fructose was determined in vitro using the intestinal sheet method. Northern and Western blotting, and immunohistochemistry were used to determine the abundance of GLUT5 and GLUT2. Results: When expressed on the basis of mucosal surface area, jejunal fructose uptake was increased in 9 and 24 month as compared with 1 month old animals fed SFA. PUFA fed animals demonstrated increased fructose uptake at 24 months as compared to younger animals. Ileal fructose uptake was increased with SFA versus PUFA in 9 month old rats, but was reduced with SFA in 1 and 24 month olds. Variations in GLUT2 and GLUT5 abundance did not parallel changes in uptake. Conclusions: These results indicate that 1) age increases fructose uptake when expressed on the basis of mucosal surface area; 2) age influences the adaptive response to dietary lipid modifications; and 3) alterations in fructose uptake are not explained by variations in GLUT5 or GLUT2.