Clinical Briefs: Ginseng and Hypertension.

Clinical Briefs: Ginseng and Hypertension

Source: Stavro PM, et al. Long-term intake of North American ginseng has no effect on 24-hour blood pressure and renal function. Hypertension 2006;47:791-796. Epub 2006 Mar 6.

Goal: To evaluate the effect of North American ginseng (NAG) on mean 24-hour ambulatory blood pressure (ABP) and renal function after 12 weeks use in hypertensive subjects.

Design: Randomized, controlled, double-blind crossover trial.

Subjects: Fifty-two people from Toronto with hypertension (data from 37 subjects, 30 men, were included in the main analysis).

Methods: Subjects recruited through newspaper advertisements were randomized to receive, following a four-week open label placebo run-in, 3 g NAG followed by cornstarch placebo, or cornstarch placebo followed by 3 g NAG (identical capsules). Participants ingested the capsules orally in divided doses (bid) during the first 12 weeks (between 7-9 am and again between 7-9 pm). Following an eight-week washout period subjects took the crossover treatment for 12 weeks in the same manner. ABP monitors were fitted, weight was recorded, and blood samples were drawn at the beginning of the run-in and at study's end after a 10-12 hour fast overnight and discontinuation of blood pressure medications (8 hours). During the two days that the ABP monitor was worn (activated between 9-10 am) no NAG or placebo was ingested. Participants also filled out a 24-hour diary of activity, sleep, and drug schedules. Primary outcome measure was mean 24-hour ambulatory systolic blood pressure at 12 weeks. Additional blood pressure measures, body weight, and serum cystatin C levels were secondary outcome measures.

Results: No significant treatment effect was found for mean 24-hour systolic blood pressure or most other blood pressure parameters (including day and nighttime readings). At week 12, diastolic blood pressure readings for the NAG group were higher at 1 pm than in the placebo group, but this was considered insignificant since mean daytime and 24-hour diastolic blood pressure readings did not differ between the groups. No significant change was noted in body weight or serum cystatin C between the two groups at the end of the study.