L-arabinose and D-xylose: sweet pentoses that may reduce postprandial glucose and insulin responses

Abstract

Background: Diets inducing high fluctuations in plasma glucose levels are linked to type 2 diabetes. L-arabinose and D-xylose have been hypothesized to inhibit intestinal sucrase activity, delay sucrose digestion, and reduce glycaemic and insulinaemic responses. However, few human studies have assessed this using realistic foods.
 Objective: We investigated the effects of the addition of L-arabinose and D-xylose on glucose homeostasis using a fruit-based drink and the effect of L-arabinose using a muffin.
 Design: Fifteen males participated in two double-blind, randomized cross-over experiments. In experiment A, three drinks were tested: (1) L-arabinose, (2) D-xylose and (3) control drink. In experiment B, two muffins were tested: (1) L-arabinose and (2) control muffin. All products consisted of ~50 g available carbohydrates, and L-arabinose or D-xylose was added as 10% of sucrose. Pre- and post-ingestive plasma glucose and insulin levels were measured at fixed time points up to 180 min after consumption.
 Results: Glucose and insulin peaks were lower after the L-arabinose and D-xylose drink than the control drink (P < 0.01). After consumption of the muffin, glucose responses were not significantly different; however, the insulin peak and incremental area under the curve (iAUC) tended to be lower for the L-arabinose muffin.
 Conclusion: L-arabinose and D-xylose are functional ingredients that can potentially lower the post-ingestive glycaemic and insulinaemic responses when added to realistic foods. However, the efficacy of applying L-arabinose appears to depend on the food matrix. Addition of these compounds needs further testing in other foods and in other populations, such as pre-diabetics.

Efficacy of L-Arabinose in Lowering Glycemic and Insulinemic Responses: The Modifying Effect of Starch and Fat

“…This resulted in an estimated sample size of minimal 20 participants. Previous studies from our lab [ 13 , 14 ] showed dropout rates of 17% and 11%. Taking into account a safe dropout rate of 20%, it was decided to enrol 24 subjects.…”

“…Sample size estimations were performed with the software program G-power (University of Kiel, Kiel, Germany). For all calculations, a paired Student’s t -test was assumed, with a two-tailed t -test with α = 0.05, power = 0.8, and SD of 0.75 mmol/L (obtained from previous experiments [ 13 , 14 ]). Furthermore, an effect of 0.5 mmol/L was assumed to be relevant in this population, which means an effect size (dz) of 0.67.…”

“…Several randomised clinical trials with healthy subjects show that adding L-arabinose to simple drinks or gels containing sucrose reduces postprandial glycemic responses significantly [ 10 , 11 , 12 ]. When 0.9 g L-arabinose was added to a tropical fruit-flavoured drink sweetened with 10 g sucrose, glycemic and insulinemic responses were lowered by 9% and 35%, respectively [ 13 ]. In addition, the replacement of 30% sucrose by L-arabinose lowered glycemic and insulinemic responses by 22% and 67% [ 14 ].…”

“…However, the efficacy of L-arabinose is less evident for more complex foods. For example, no effect was found on glucose or insulin responses when L-arabinose was incorporated into a mixed breakfast meal [ 15 ], cereals [ 14 ], and when sucrose was replaced with L-arabinose in muffins [ 13 ]. Although in the latter two studies no effect was found on glycemic response, trends towards lower insulinemic responses were observed [ 13 , 14 ].…”

“…For example, no effect was found on glucose or insulin responses when L-arabinose was incorporated into a mixed breakfast meal [ 15 ], cereals [ 14 ], and when sucrose was replaced with L-arabinose in muffins [ 13 ]. Although in the latter two studies no effect was found on glycemic response, trends towards lower insulinemic responses were observed [ 13 , 14 ]. These findings suggest that L-arabinose may have had an inhibiting effect on sucrose breakdown, but that the net effects could not be observed in the circulating glucose levels of healthy subjects.…”