INFLUENCE OF ACARBOSE-INDUCED STARCH MALABSORPTION ON THE GENERATION OF INTERMEDIATES BY COLONIC FERMENTATION IN HEALTHY-SUBJECTS

A quantitatively and qualitatively altered colonic fermentation of una bsorbed carbohydrates was found to be the cause of recurrent D-lactic acidosis in patients with a short bowel syndrome or after jejuno-ileal bypass surgery, The alpha-glucosidase inhibitor acarbose which is wid ely used as a blood glucose-lowering oral drug in the therapy of NIDDM may cause significant carbohydrate malabsorption and subsequent ferme ntation, The aim of this study was to investigate whether D-lactate, a product of human intermediary metabolism, accumulates during a four w eek administration of acarbose in addition to a starch-rich diet. Ten healthy volunteers had a semi-standardized basal diet containing at le ast 130 g starch per day controlled by a weekly dietary protocol. They were, given acarbose in increasing doses from 0 mg during week one to 3 x 200 mg/day during week 5. At the end of each week they ingested a pasta meal containing 100 g of starch, with the following hourly meas urements of breath H-2, venous blood concentrations of glucose ethanol ? L-lactate, D-lactate, capillar) blood DH, and base excess for 8 hour s, A stimulated fermentation activity was demostrated by a significant increase of fasting and postprandial breath H-2, from week 1 to 5. Me an values for ethanol. L-lactate, pH, and negative base excess were fo und in the physiological range. No clinically important changes were f ound during acarbose administration. Even though mean fasting levels o f D-lactate doubled from 38 mu mol/l after week 1 to 84 mu mol/l after week 5, the postprandial course of this intermediate showed no furthe r increase. Even the highest measured D-lactate value of 177 mu mol/l was below the upper normal limit of 200 mu mol/l. We conclude from the se results that in contrast to some special situations like the small bowl syndrome or intestinal bypass surgery, acarbose induced chronic c arbohydrate fermentation in an unaltered gut anatomy is without risk o f clinically relevant D-lactate accumulation. Since this intermediate is principally removed from blood by renal filtration, our results sti ll need to be confirmed in patients with renal failure, which is commo n in long-term diabetic subjects.