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

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.