Figure 3.

Dependence of fructose resorption on the amount of fructose consumed, expressed as proportion of pathological H2 breath test results (>20 ppm increase)

This fructose resorption curve, calculated from the results of several studies, shows that doses of fructose from around 40 g upwards result in pathological H2 breath test results in more than 60% of persons, although not all of them develop symptoms (10, 19– 23). The resorption capacity for fructose is limited in humans (9– 11, 26, e16). Various factors can act to modulate fructose resorption (Figure 3): displacement of the fructose resorption curve to the left leads to manifestations of malabsorption on intake of lower amounts of fructose (decrease in tolerance), while displacement to the right results in tolerance of higher quantities of fructose. The extent to which congenital or acquired mechanisms influence the affinity and function of the transporter has not yet been conclusively established (9, 10, 19, 33)