Effect of a traditional Japanese garlic preparation on blood pressure in prehypertensive and mildly hypertensive adults

Abstract

Numerous clinical studies have used differing garlic preparations leading to controversial results with regard to the hypotensive effect of garlic. This randomized, double-blind, placebo-controlled study was designed to determine the effect of a traditional Japanese garlic homogenate-based supplementary diet (GH diet) product on blood pressure (BP) in subjects with prehypertension and in those with mild hypertension. In total, 34 eligible subjects with prehypertension and 47 with mild hypertension were treated with a daily dose of GH diet (300 mg as dried garlic homogenate; n=16 and 23, respectively) or placebo (n=18 and 24, respectively) for 12 weeks. Of these, 32 prehypertensive subjects (15 on the GH diet and 17 on the placebo) and 40 mildly hypertensive subjects (19 on the GH diet and 21 on the placebo) completed the study and were subjected to efficacy analyses. Systolic and diastolic BPs were monitored at weeks 4, 8 and 12 during the treatment and at post-week 4 following the termination of the treatment. The GH diet induced significant reductions of systolic BP (of between 6.6 and 7.5 mmHg) and diastolic BP (of between 4.6 and 5.2 mmHg) compared with the placebo subsequent to 8 and 12 weeks of treatment. A 12-week intake of the GH diet did not cause any clinically problematic side-effects. We conclude that the GH diet was well tolerated, and had a clinically relevant hypotensive effect in adults with mild hypertension, but not in those with prehypertension.

Effect of Garlic on Blood Pressure: A Meta‐Analysis

“…Our findings were consistent with a previous meta‐analysis by Ried and colleagues in 2008 . We believe our meta‐analysis has some advantages as it included new trials and evaluated the methodological quality of the selected trials using the nine quality criteria proposed by the Dutch Cochrane Centre in 2009 (Table). We reanalyzed the high‐quality trials after the low‐quality trials were removed and found that a significant reduction in both SBP and DBP still existed in the garlic‐treat group.…”

“…Among the 17 trials, one included two separate random‐controlled trials that involved hypertensive patients and normotensive individuals, therefore this trial was counted as two trials. Therefore, our meta‐analysis included a total of 18 trials, seven of which comprised hypertensive individuals and six normotensive individuals, another five included both hypertensive and normotensive individuals.…”

“…At first, garlic was thought to be useful in decreasing serum cholesterol concentration . Recently, several studies have shown that garlic supplements can decrease BP . However, the meta‐analysis by Ackermann and colleagues found that garlic had no significant effects on BP .…”

“…Phenolic and steroidal compounds in garlic also have pharmacologic effects . Evidence from human trials suggests that garlic might be beneficial in the treatment of hypertension . However, the results from several previous meta‐analysis were contradictory .…”

A review on the effects of Allium sativum (Garlic) in metabolic syndrome

“…Results showed that consumption of 300 mg/day of dehydrated garlic homogenate in subjects with mild hypertension and prehypertension lowered systolic and DBP in mild hypertension patients but not in prehypertension. The garlic homogenate diet was tolerated without any clinically significant untoward effects [69]. In a randomized study, uncontrolled hypertensive patients ingested one, two, or four capsules daily of aged garlic extract (240/480/960 mg), and blood pressure was assessed at 4, 8, and 12 weeks.…”