Metabolic investigations after xylitol infusion in human subjects

Evidence has been sought for minor degrees of thiamin and pyridoxine deficiency in patients undergoing surgery who have been infused with xylitol as a parenteral nutrient. Some metabolic changes which are associated with this practice have been studied; the findings are compared with those obtained in similar patients infused with glucose solutions. The thiamin status of all of the subjects was normal. Some of the patients showed slight biochemical evidence of pyridoxine deficiency, but there were no untoward effects of xylitol infusion. The concentration of oxalate in the blood and the excretion of oxalate in the urine did not exceed the normal range in any patient. The plasma and urine orthophosphate and urinary pyrophosphate levels decreased in association with the infusion of both xylitol and glucose. Plasma pyrophosphate and calcium levels, and the urinary calcium level, were essentially unaltered. A detailed quantitative study of the urinary organic acid excretion by means of gas chromatography/mass spectrometry showed that there was an abnormal glycolic aciduria and tetronic aciduria associated with xylitol infusion, but not with glucose infusion. There was no evidence of increased oxalate excretion in any patient by this method. The biochemical and clinical significance of these findings is discussed.