Table 1.
Characteristics of randomised controlled trials included in meta-analysis examining the effect of garlic on blood pressure
| Source | Study design; Intervention/control groups | Type of garlic preparation, Dosage, Duration | Number of participants in intervention vs control group | Mean SBP (SD) at start/end of intervention vs control in mm Hg | Mean DBP (SD) at start/end of intervention vs control in mm Hg |
| Kandziora J 1988 (Study 1), [11] | Parallel, | Garlic powder (Kwai), | 20/20 | Garlic: 174 (4)/158 (10) | Garlic: 99 (3)/83 (4) |
| Diuretic drug (Dytide H) + garlic/drug only | 600 mg/d, | (standing) | Control: 175 (8)/169 (6) | Control: 98 (5)/90 (3) | |
| 12 wks | |||||
| Auer et al. 1990, [12] | Parallel, | Kwai, | 24/23 | Garlic: 171 (21.6)/152 (19.6) | Garlic: 102 (13)/89 (4.4) |
| Garlic/placebo | 600 mg/d, | Control: 161 (19)/153 (19) | Control: 97 (12.9)/93 (10.6) | ||
| 12 wks | |||||
| Vorberg & Schneider 1990, [13] | Parallel, | Kwai, | 20/20 | Garlic: 144.5 (13.4)/138.5 (4.3) | Garlic: 91 (3.9)/87 (3.7) |
| Garlic/placebo | 900 mg/d, | Control: 144 (10.4)/147 (7.1) | Control: 88 (6.1)/90 (3.7) | ||
| 16 wks | |||||
| Holzgartner et al. 1992, [14] | Parallel, | Kwai, | 47/47 | Garlic: 143.4 (15.4)/135.4 (14.6) | Garlic: 82.8 (10.5)/78.6 (9.3) |
| Lipid-lowering drug (Benzafibrate) + garlic/drug only | 900 mg/d, | Control: 140.6 (18.7)/137.2 (14.6) | Control: 82.4 (9.5)/78.4 (9.2) | ||
| 12 wks | |||||
| Kiesewetter et al. 1993, [15] | Parallel, | Kwai, | 32/32 | Not reported | Garlic: 84.7 (13.7)/81.7 (12.1) |
| Garlic/placebo | 800 mg/d, | Control: 83.3 (11)/81.7 (11) | |||
| 12 wks, | |||||
| Jain et al. 1993, [16] | Parallel, | Kwai, | 20/22 | Garlic: 129 (13)/130 (17) | Garlic: 82 (6)/81 (10) |
| Garlic/placebo | 900 mg/d, | Control: 128 (10)/127 (12) | Control: 83 (8)/82 (6) | ||
| 12 wks | |||||
| Saradeth et al. 1994, [17] | Parallel, | Kwai, | 25/27 | Garlic: 125 (17)/127.4 (16) | Garlic: 80.8 (8)/82.7 (10) |
| Garlic/placebo | 600 mg/d, | Control: 124.6 (15.6)/122.8 (12.5) | Control: 81.8 (9.4)/81.1 (9.4) | ||
| 15 wks | |||||
| Simons et al. 1995, [18] | Crossover, | Kwai, | 28/28 | Garlic: 127 (14)/119 (7) | Garlic: 80 (8)/76 (5) |
| Garlic/placebo | 900 mg/d, | Control: 127 (14)/122 (10) | Control: 80 (8)/76 (6) | ||
| 12 wks | |||||
| Steiner et al. 1996, [19] | Parallel study arm, | Aged garlic extract, | 41/41 | Garlic: 134 (14)/126 (14) | Garlic: 84 (8.6)/82.3 (9) |
| Garlic/placebo | 2400 mg/d, | Control: 134 (11)/129.6 (12) | Control: 85 (7.4)/81.7 (8) | ||
| 23 wks | |||||
| Adler & Holub 1997, [20] | Parallel, | Kwai, | 12/13/10/11 | Garlic: 123.3 (14.5)/118.5 (9.4) | Garlic: 83.2 (2.5)/80 (2.2) |
| Garlic/garlic+fish oil/fish oil/placebo | 900 mg/d, | Control: 118.3 (3.2)/119.6 (3) | Control: 79.6 (2.2)/80.9 (2) | ||
| 12 wks | |||||
| Zhang et al. 2000, [21] | Parallel, | Distilled garlic oil, | 14/13 | Garlic: 117 (8)/113.5 (6.4) | Garlic: 72 (7)/68.2 (9.4) |
| Garlic/placebo | 12.3 mg/d, | Control: 109 (9)/109.9 (9.4) | Control: 64 (7)/62.8 (5.4) | ||
| 16 wks |
SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation; vs, versus; mm Hg, millimetre mercury; mg/d, milligram per day; wks, weeks; mths, months.