Korean red ginseng improves glucose and insulin regulation in type 2 diabetics.
Design: Randomized, double-blind, placebo-controlled, crossover clinical trial
Participants: 19 participants (mean age 64 [+ or -] 2 years old, BMI: 28.9 [+ or -] 1.4 kg/[m.sup.2], and Hb[A.sub.1c]: 6.5%) with well-controlled type 2 diabetes.
Study Medication and Dosage: Following a 4-week placebo run-in phase, participants were randomized to receive either 2 g of a Korean red ginseng (Panax ginseng) rootlet preparation (KRG; Korea Ginseng Manufacturing Plant, National Agricultural Cooperative Federation, Chung-buk, Korea) or a placebo 40 minutes before each meal, three times per day (total dose of 6 g/day). This was followed by another 4-week washout phase and then randomization to the alternate treatment for the second phase of the study.
Duration: 12-week treatment phase
Outcome Measures: Outcome measures included the primary endpoint [HB[A.sub.1c], as well as fasting and 75-g oral glucose tolerance test, plasma glucose, plasma insulin and insulin-sensitivity indices. Safety measures included markers of hepatic (AST, ALT), renal (serum urea, serum creatinine, 24 hour creatinine clearance), and hemostatic (prothrombin time, activated partial thromboplastin time, and blood pressure). During each treatment phase, participants were seen at the clinic every 6 weeks. They were asked to submit 7-day dietary records during the last week of each treatment period. At weeks 0 and 12 of each treatment phase, a 75 g oral glucose tolerance test with venous samples obtained at 0, 30, 60, 90, and 120 minutes and a 24-hour ambulatory blood pressure monitoring study were conducted.
Key Findings: There was no significant change on the [Hb[A.sub.1c] during the study. However, the participants [Hb[A.sub.1c] remained well controlled throughout the study ([HbA.sub.1c] = 6.5%). KRG treatment decreased 75g-oral glucose tolerance test plasma glucose indices by 8-11 %, and fasting-plasma insulin and the 75g-oral glucose tolerance test plasma insulin indices by 33-38%, and increased fasting-insulin sensitivity and 75g -insulin sensitivity indices by 33%;, compared with placebo (p < 0.05 for all measures). Safety measures remained unchanged during the study.
Practice Implications: Led by Dr. Vladimir Vuksan of the University of Toronto, this study suggests that 6 g/ day of Korean Red Ginseng rootlets helps maintain glycemic control and improves plasma glucose and plasma insulin regulation. It is important to note that the treatment did not improve the primary endpoint [Hb[A.sub.1c]. The batch and dose for this study were selected based on extensive acute screening studies. (1) These results are in contrast to earlier work done by Dr. Vuksan's group which suggest that American ginseng (Panax quinquefolius) was effective in improving glycemic control over a 12-week period (2). Hopefully, future studies by this group will look at larger populations of type 2 diabetics and compare the efficacy of the two different ginseng species for improving glycemic control.
(1) Sievenpiper JL, Sung MK, Di Buono M, et al. Korean red ginseng rootlets decrease acute postprandial glycemia: results from sequential preparation-and dose-finding studies. J Am Coll Nutr 2006;25:100-7.
(2) Vuksan V, Xu Z, Jenkins AL, et al. American ginseng improves long-term glycemic control in type 2 diabetes: double-blind placebo controlled crossover trial. Diabetes 2000;49(Suppl 1):A95.
Author: Donald Brown, ND
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|Title Annotation:||ABSTRACTS OF INTEREST|
|Article Type:||Clinical report|
|Date:||Jun 1, 2008|
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