Fructose and sorbitol

If the ratio [NAD+] / [NADH] in a cell were 500 and the ratio [NADP+] / [NADPH] were 0.002, what concentrations of fructose and sorbitol would be in equilibrium with 0.1 mM glucose ... 

Rumessen, J.J. and Gudmand-Hpyer, E., Fructans of chicory intestinal transport and fermentation of different chain lengths and relation to fructose and sorbitol malabsorption, Am. J. Clin. Nutr., 68, 357-364, 1998. 

Mixtures of the monotriethanolamine titanate and polyols, such as fructose and sorbitol, imparted thixotropic properties to polymer-containing cement (107). A similar reaction of triethanolamine and tetraalkyl titanates previously treated with stearic acid gives the corresponding 1-acyloxytitatranes (108). Aqueous dispersions of these materials can be used to treat fabrics to impart a high degree of water repellency. 

Hereditary fructose intolerance affects one in 21 000 persons, and there have been more than 12 severe complications caused by these solutions, several lethal. Since a prior history of fructose intolerance is often not obtained, it has been argued that the use of fructose- and sorbitol-containing infusion fluids must be regarded as offering doubtful advantage but carrying definite lethal risk, and that their use should be discontinued. A modified intravenous fructose tolerance test should at least be carried out before infusions of fructose or sorbitol are giveu (8). 

Sachs M, Asskali F, Forster H, Encke A. Wiederholte perioperative Application von Fructose und sorbit bei einer Patientin mit hereditarer fructoserntoleranz (HFI). [Repeated perioperative administration of fructose and sorbitol in a female patient with hereditary fructose intolerance (HFI).] Z Ernahrungswiss 1993 32(l) 56-66. 

Fructose has been used as an alternative to dextrose in parenteral nutrition, but its use is not recommended by some because of the risk of lactic acidosis. Although popular in many countries, it has therefore been suggested that the use of intravenous infusions containing fructose and sorbitol should be abandoned. ... 

Sucrose, glucose, fructose and sorbitol were separated and quantitated by HPLC. The sample preparation procedure included removal of acids by percolating the juice through a minicolumn... 

Ledochowski M, Widner B, Bair H, et al Fructose- and sorbitol-reduced diet improves mood and gastrointestinal disturbances in fructose malabsorbers. Scand J Gastroenterol 35 1048-1052, 2000... 

The table below gives the concentration in g H of sucrose, glucose, fructose and sorbitol in apple juice from three different sources. A, B and C. Carry out an LDA and evaluate the method using cross-validation. 

THE UTILIZATION OF XYLITOL, FRUCTOSE AND SORBITOL Harald Forster... 

The increased lactate formation during fructose metabolism is probably due to inhibition of diphosphofructose aldolase by accumulation of fructose-l-phosphate. This enzyme is involved in gluconeogenesis as well as in glucose breakdown and its inhibition would channel the metabolism of fructose to pyruvate and lactate. In fact, the lactate formation following xylitol administration was minimal, whereas fructose and sorbitol were nearly equally effective in this respect. 

The accumulation of sorbitol and consequent uptake of water leads to opacification of the lens, 1.e. diabetic cataract. In diabetic rabbit lens, formation of fructose and sorbitol was enhanced, while that of myo-inositol decreased, relative to normal lens. The following polyols have been identified in human urine for the first time 4-deoxythreitol, 4-deoxyerythritol, 5-deoxyxylitol, 5-deoxy-... 

All the polyoles have proved to exhibit undesirable or dangerous side effects in animal studies and when used therapeutically in man this has led in some countries (such as Australia) to a proliibi-tion on the use of xylitol for intravenous nutrition. Large quantities of fructose and sorbitol lead to a metabolic acidosis, the severity of which cannot be foreseen, as well as hyperuricaemia, and reduction in hepatic stores of nucleotide-adenine and inorganic phosphates. Xylitol produces identical effects (with hyperuricaemia being particularly pronounced) as well as osmotic diuresis with loss of electrolytes and, in some cases, formation of crystalline deposits in the kidneys and brain. 

Some months later, a statement by the Australian Drug Evaluation Committee reflected similar thinking and made closely similar recommendations (52). It was pointed out, inter alia, that the rapid metabolism of fructose and sorbitol can cause rapid accumulation of uric and lactic acids as well as phosphate depletion, especially in states of anoxia, and that acidosis and decreased tissue energy metabolism can occur. Glucose has, among other things, the advantage that it poses no risk to patients with familial laevulose intolerance. 

Seino, H., T. Uchibori, T. Nishitani, S. Inama.su, Enzymatic synthesis of carbohydrate esters of fatty acid. I Esterification of sucrose, glucose, fructose and sorbitol,/. Am. Oil Chem. Soc., 1984,6/, 1761-1765. 

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