Differences in acute metabolism of fructose between hemodialysis patients and healthy subjects

The consumption of fructose has increased dramatically during the last few decades and parallels the epidemics of obesity, metabolic syndrome, diabetes and chronic kidney disease (CKD). Fructose occurs naturally e. g. in fruit and in honey (rich in this monosaccharide) and as sucrose (table sugar). The effects of fructose have been attributed to the transient increases in serum uric acid levels during its metabolism. Recent research, also in CKD patients, has linked fructose to dysmetabolism of lipids, glucose and oxidative radicals. However, a general consensus of the potentially harmful effects of fructose is lacking. We improved a sensitive inulin assay for fructose measurement in serum and plasma and tested its accuracy in an acute experiment following consumption of pure fructose in controls. In addition, fructose and uric acid were analyzed postprandially during 240 min in six maintenance hemodialysis (HD) patients and nine healthy subjects consuming 190 ml cream/75 g sucrose in a fasting state. Whereas the fructose levels reached a maximum level after 60 min in controls they had not even started to decrease at 240 min in HD-patients. Likewise, while uric acid levels remained stable in controls they increased by 10% in HD patients at 240 min following the meal. In conclusion, a glucose and fat rich meal is associated with delayed absorption and/or metabolism of fructose in HD patients as well as increased serum uric acid levels.