American ginseng (Panax quinquefolius L) reduces postprandial glycemia in nondiabetic subjects and subjects with type 2 diabetes mellitus.

BACKGROUND: Despite a lack of medical evidence to support its therapeutic efficacy, the use of herbal medicine has increased considerably. Ginseng, one of the most widely used herbs, is hypothesized to play a role in carbohydrate metabolism and diabetes mellitus. We therefore undertook a preliminary short-term clinical study to assess whether American ginseng (Panax quinquefolius L) affects postprandial glycemia in humans. DESIGN: On 4 separate occasions, 10 nondiabetic subjects (mean [+/-SD] age, 34+/-7 years; mean [+/-SD] body mass index [BMI], 25.6 +/- 3 kg/m2) and 9 subjects with type 2 diabetes mellitus (mean [+/-SD] age, 62 +/- 7 years; mean [+/-SD] BMI, 29 +/- 5 kg/m2; mean [+/-SD] glycosylated hemoglobin A1c, 0.08+/-0.005) were randomized to receive 3-g ginseng or placebo capsules, either 40 minutes before or together with a 25-g oral glucose challenge. The placebo capsules contained com flour, in which the quantity of carbohydrate and appearance matched the ginseng capsules. A capillary blood sample was taken fasting and then at 15, 30, 45, 60, 90, and 120 (only for subjects with type 2 diabetes mellitus ) minutes after the glucose challenge. RESULTS: In nondiabetic subjects, no differences were found in postprandial glycemia between placebo and ginseng when administered together with the glucose challenge. When ginseng was taken 40 minutes before the glucose challenge, significant reductions were observed (P<.05). In subjects with type 2 diabetes mellitus, the same was true whether capsules were taken before or together with the glucose challenge (P<.05). Reductions in area under the glycemic curve were 18%+/-31% for nondiabetic subjects and 19+/-22% and 22+/-17% for subjects with type 2 diabetes mellitus administered before or together with the glucose challenge, respectively. CONCLUSIONS: American ginseng attenuated postprandial glycemia in both study groups. For nondiabetic subjects, to prevent unintended hypoglycemia it may be important that the American ginseng be taken with the meal.

American ginseng improves glycemia in individuals with normal glucose tolerance: effect of dose and time escalation.

OBJECTIVE: We studied the effect of escalating the dose and administration time of American ginseng (AG, Panax quinquefolius L.) in nondiabetic individuals to achieve further improvements in glucose tolerance seen previously when 3 g of AG was taken 40 minutes before a 25 g glucose challenge. METHODS: Ten nondiabetic individuals (6M:4F; mean +/- STD: age = 41 +/- 13 years, BMI = 24.8 +/- 3.5 kg/m2, FBG = 4.5 +/- 0.1 mmol L(-1)) on 12 separate occasions, randomly received 0 (placebo), 3, 6 or 9 g of ground AG root at 40, 80, or 120 minutes before a 25 g oral glucose challenge. Capillary blood glucose was measured prior to ingestion of AG or placebo capsules and at 0, 15, 30, 45, 60 and 90 minutes from start of challenge. RESULTS: Compared with the placebo, 3, 6 and 9 g of AG reduced (p<0.05) postprandial incremental glucose at 30, 45 and 60 minutes; also, 3 and 9 g of AG did so at 90 minutes. At 60 minutes, 9 g of AG reduced incremental postprandial glucose relative to 3 g of AG (p<0.05). All AG doses reduced (p<0.05) area under the incremental glucose curve (3 g, 26.6%; 6 g, 29.3%; 9 g, 38.5%). AG taken at different times did not have an additional influence on postprandial glycemia. CONCLUSIONS: In nondiabetic individuals, 3, 6 or 9 g of AG taken 40, 80 or 120 minutes before a glucose challenge similarly improved glucose tolerance.