Oral carbohydrate loading with 18% carbohydrate beverage alleviates insulin resistance.

Preoperative 12.6% oral carbohydrate loading is an element of the Enhanced Recovery After Surgery (ERAS) protocol aimed at alleviating postoperative insulin resistance; however, in Japan, beverages with 18% carbohydrate content are generally used for preoperative carbohydrate loading. We investigated the effect of 18% carbohydrate loading on alleviating insulin resistance. Six healthy volunteers participated in this crossover-randomized study and were segregated into 2 groups: volunteers in the carbohydrate-loading group (group A) who fasted from after 9 pm and ingested 375 mL of a beverage containing 18% carbohydrate (ArginaidWaterTM; Nestle, Tokyo, Japan) between 9 pm and 12 pm, and 250 mL of the same liquid at 6:30 am. Volunteers in control group (group B) drank only water. At 8:30 am, a hyperinsulinemic normoglycemic clamp was initiated. Glucose infusion rate (GIR) and levels of ketone bodies and cytokines (IL-1β, IL-6, and TNF-α) before clamping were evaluated. p<0.05 was considered statistically significant. Levels of blood glucose, insulin, and cytokines at the start of the clamp were similar in both the groups. The GIR in group A was significantly higher than that in group B (11.5±2.4 vs 6.2±2.2 mg/kg/min, p=0.005), while blood ketone body levels were significantly lower in group A (22±4 vs 124±119 μmol/L, p=0.04). Preoperative 18% carbohydrate loading could prevent the decrease in insulin sensitivity and suppress catabolism in healthy volunteers. Thus, carbohydrate loading with a beverage with 18% carbohydrate content might contribute to improvements in perioperative management.