Preload time-dependent effects of Panax ginseng on postprandial glucose tolerance. A randomized controlled study in...

Panax ginseng (P. ginseng, C.A. Meyer) is suggested to improve blood glucose regulation, but evidence remains inconsistent. We examined whether consuming P. ginseng as a preload before a carbohydrate-rich meal modulates postprandial glucose and insulin responses.

In a randomized, double-blind, crossover trial, 22 healthy middle-aged adults consumed P. ginseng tablets containing 32 mg total ginsenosides (primarily Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd) or an identical placebo without ginsenosides at three time points prior to a standardized breakfast: 90 min, 45 min, and immediately before meal initiation.

Compared with placebo, P. ginseng ingested 90 min prior to the meal reduced 0-150 min postprandial blood glucose incremental areas under the curves (iAUC) by 29% (P < 0.001) and maximum individual glucose peaks (iPeak) by 26% (P < 0.001). When P. ginseng was ingested 45 min prior to the meal, postprandial iPeaks were reduced by 15% (P < 0.01). Postprandial insulin iAUCs decreased by 24% (P < 0.001) and 23% (P < 0.01) when ginseng was consumed 90 and 45 min, respectively, before the meal. Similarly, compared with placebo, the insulin iPeaks were significantly lower after ginseng intake at 90 or 45 min prior to the meal (-23%, P < 0.001 and -15%, P < 0.01, respectively). No effects on blood glucose or insulin responses were observed when ginseng was taken immediately before the meal (P > 0.05).

Preload timing is critical for optimizing ginseng's glucoregulatory effects, supporting its potential role in dietary strategies for glycemic management.Trial registered at ClinicalTrials.gov (NCT02392819). URL:clinicaltrials.gov/study/NCT02392819.