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The mean maximal turnover capacity for intravenously infused xylitol was determined in women during parturition and after surgery. Although both conditions are considered as stress situations, the values for maximal turnover differed by 100%. The mean maximal turnover under labour was 0.31 g/kg/h compared to 0.76 g/kg/h on the first day after surgery.

3 groups (6 control persons, 6 patients with liver cirrhosis, 6 patients with diabetes mellitus) were infused with 20% (w/v) carbohydrate mixture (glucose/fructose/xylitol, 1:2:1) for 48 hours. The metabolical status was controlled in defined intervals by means of 39 different laboratory parameters. The infusion rate was supposed to be 0.25 g carbohydrates/kg B. W. and hour. There were no significant changes in blood glucose levels in any of the 3 groups. However we could observe a slight but constant increase in lactate and triglyceride concentrations. Free fatty acids and keton bodies were suppressed on a low level. Only the diabetics showed a significant renal carbohydrate loss with up to 15% of the amount administered. No clinically relevant side effects were observed.

Due to the metabolic alterations following surgery, glucose is not completely oxidized but is converted into glycogen and lipids. Therefore we analysed 2 groups of 15 patients following surgery. They received parenteral nutrition with identical nitrogen (N = 0.28 g/kg/d) and lipid (1.5 g/kg/d) intake, whereby only the composition of carbohydrates was varied. Group I received exclusively glucose = 0.22 g/kg/h, and group II the combination fructose-glucose-xylitol in a proportion of 2:1:1 at the same infusion rate. The study lasted approximately 10 days. We found decreased exogenous insulin requirements and an increase in the NEFA levels with a maximum on the 3rd and 4th day in group II. There were no significant differences in the levels of either albumin, prealbumin or retinol-binding protein, nor were any hepatic or renal alterations related to the xylitol infusion observed. Xylituria was 6.13 +/- 3% of the amount infused. In our opinion, the partial substitution of glucose in group II led to a better utilisation of the infused energy supply, and to less insulin stimulation, which facilitated the mobilization of endogenous energy sources such as fatty acids, although we did not succeed in increasing the protein synthesis.

By central venous catheterization, 6 control persons, 7 patients with liver cirrhosis and 6 patients with diabetes mellitus were infused for 48 h with a 20% (w/v) mixture of glucose/xylitol (1:1). The infusion 48 h with a 20% (w/v) mixture of glucose/xylitol (1:1). The infusion rate of 0.125 g monosaccharide/kg/h could be maintained with minor deviations. There were no significant changes in blood glucose levels using this infusion regimen. Lactate levels, however, did increase constantly during the whole infusion period. In the liver group as well as in the diabetic group we could measure values between 1.5 and 3.9 mmol/l. Triglycerides increased solely in the diabetic group. Uric acid concentrations were elevated in all 3 groups. Clinically significant side effects were not observed.

Postoperative hypocaloric peripheral-venous nutrition with the same content of amino acids (1 g/kg BW/d) and carbohydrates (2 g/kg BW/d) was performed in two groups of patients, one group receiving xylitol and sorbitol (1:1), the other pure glucose only. Regarding the behavior of different parameters of the protein metabolism it could be demonstrated, that glucose supply although improving the N-retention by 12% had no significant favourable effect on viscerally synthesized plasma proteins in contrast to the polyols. Because of the nearly identical endogenous insulin stimulation in both groups it can be assumed, that glucose supply inhibits lipolysis completely thus reducing free fatty acids levels in plasma and therefore increasing peripheral insulin sensitivity resulting in enhanced utilisation of the amino acids supplied mainly in muscle. Additionally the improvement in synthesis of visceral proteins supplying polyols can be also due to a specific effect of these substrates, because the known activation of pentose-phosphate-cycle, especially by xylitol, increases RNA-synthesis and therefore lately improving protein synthesis, too.

Basic caloric needs of patients with compensated liver cirrhosis and healthy controls were supplied for 48 h with mixtures of glucose, fructose, sorbite, and xylit. Mixed solutions (20% w/v) containing glucose + fructose (n = 6), glucose + sorbite (n = 36), glucose + xylit (n = 37) in a 1:1 ratio, and glucose + fructose + xylit (n = 6) in a 1:2:1 ratio as well as glucose alone (n = 6) were administered in a dosage of 0.25 g/kg/h each. Utilization of the monosubstances, corresponding blood levels, and the effects on parameters of carbohydrate and lipid metabolism were frequently controlled. In contrast to mixed solutions, infusion of glucose alone caused a pronounced increase of the insulin levels and hyperglycemia in some patients suffering from liver cirrhosis. In both groups infusion of glucose + xylit was accompanied by a rise of uric acid levels. In liver cirrhotics a permanent decrease of phosphate as well as an increase of xylit concentrations were observed. These changes were not seen with xylit lowered to 50%, in glucose + fructose + xylit infusion. Therefore, we recommend to restrict xylit in liver cirrhotics to 100/24 h. No significant changes of blood gas measurements, ph values, hyperlactatemia, or lactic acidosis were seen. There was no difference in the anticatabolic, antilipolytic, and antiketogenic effect of the solutions. The least changes of all controlled parameters were observed with glucose + fructose and glucose + fructose + xylit infusions.

A 35 years old female developed a slowly progressive acute renal failure after surgical drainage of a pancreatic abscess. Due to the uncharacteristic course a renal biopsy was performed which revealed a severe obstructive renal oxalosis with concomitant interstitial nephritis. Primary oxalosis was excluded by determination of glyceric and glycolic acid in the urine. Since other preconditions for increased oxalate formation were not present it was considered as an adverse reaction to the parenteral application of xylitol. During 4 weeks of total parenteral nutrition the patient received this sugar alcohol in a dose of 3.0 g/kg/day (total dose 4480 g). In recognition of preceding autopsy studies and recent experimental investigations on the metabolic pathways from xylitol to oxalate the chances and conditions of renal deposition of calcium oxalate after administration of xylitol are discussed.

Oral tolerance tests with 30 and 50 g of xylitol were performed in 10 normal subjects adapted to taking this pentitol. A 50 g oral glucose tolerance test served as control. Continuous indirect calorimetry was carried out in 7 of these subjects to measure the effects on the metabolic rate and on the oxidation rates of carbohydrate and fat. A small and short rise in serum xylitol and low quantitites of xylitol excretion in urine were observed in both xylitol tests. Xylitol caused a small but statistically significant increase in blood glucose and plasma insulin concentrations. Plasma free glycerol diminished significantly. After xylitol the metabolic rate rose throughout the test period but the total increase was only half of that after glucose administration. There was no significant influence of xylitol on the oxidation rates of carbohydrate and lipids. The total increase in carbohydrate oxidation during 2 1/2 hours amounted to one fourth of that caused by glucose. It is suggested that xylitol, during the first two hours after ingestion, charges the body's metabolism much less than equal amounts of glucose. Therefore, the use of xylitol as a sweetener in the diet of diabetic patients seems to be justified.

18 metabolically healthy female patients with cholelithiasis, who had to undergo cholecystectomy, were divided into 3 groups and studied for a 4-day period. Group I, n = 6, received beginning on the operationday 0,19 g/kg BW X h of a polyol-mixture-solution (Sorbitol/Xylitol 1:1) and 0,86 g 1-crystalline amino acids (AA)/kg BW X day. Group II, n = 6, received beginning 24 h preoperatively only 1,14 g 1-crystalline AA/kg BW X day. Group III, n = 6, received beginning 24 h preoperatively 0,07 g Xylitol/kg BW X h, 0,03 g Glucose/kg BW X h and 1,14 g 1-crystalline AA/kg BW X day. In this study we could demonstrate that the pre-, intra- and postoperative hormonal and metabolic response is strongly influenced by different infusion regimens. Only by the simultaneous infusion of carbohydrate together with AA during the preoperative period a significant drop of triiodothyronine can be avoided. The rise of insulin and cortisol in the early postoperative period is augmented by the infusion of carbohydrates together with AA. There was no difference in growth hormone response to surgery between group I-III. All 3 groups showed a continuous fall of cholesterol during the study period.

Numerous side-effects of intravenously administered substrates have taught us that we have to reevaluate the dosages of the various substitutes of an intravenous regimen after trauma and during sepsis, whereby the limitation of glucose calories to approx. 3 g/kg B.W./day is of great metabolic importance. Additionally required calories can be provided either in the form of a lipid emulsion in a dosage of 1 to maximally 1.5 g/kg B.W./day and/or additionally xylitol in a dosage of max. 3 g/kg B.W./day.

Carbohydrates and polyols are essential constituents of intravenous nutrition. In order to better understand the problems associated with the supply of energy sources, the physiology of enteral nutrition will be covered and compared with intravenous nutrition. This review article will deal with the metabolic actions of glucose and xylitol and derive therapeutical consequences for their intravenous use during different illnesses.

Thirty-one patients scheduled for elective surgery for non-malignant abdominal disease were randomized during the first five postoperative days to two different schedules. Group I received water, electrolytes and glucose. Group II received a standard solution containing crystalline amino acids (3.8 g/l), xylitol (25 g/l) and sorbitol (25 g/l), accounting for a total of 900 cal/day. Evaluation was made with clinical, anthropometric and biochemical parameters. Among others, the following significant differences were observed at the end of the study: retinol bound protein: in group I, 4.25 +/- 1.3 and in group II, 5.38 +/- 1.53 (p less than 0.05); prealbumin: in group I, 18.7 +/- 6.24 and in group II, 24.51 +/- 7 (p less than 0.05). The significantly higher values of short-life plasma proteins observed in group II indicate that with HPPN a higher synthesis of visceral protein is promoted. These data demonstrate that HPPN improves the nutritional state during the postoperative period.