Aged Garlic Extract Reduces Blood Pressure in Hypertensives: A Dose-Response Trial

Eur J Clin Nutr. 2013 Jan;67(1):64-70. doi: 10.1038/ejcn.2012.178. Epub 2012 Nov 21.

Abstract

Background/objectives: Hypertension affects about 30% of adults worldwide. Garlic has blood pressure-lowering properties and the mechanism of action is biologically plausible. Our trial assessed the effect, dose-response, tolerability and acceptability of different doses of aged garlic extract as an adjunct treatment to existing antihypertensive medication in patients with uncontrolled hypertension.

Subjects/methods: A total of 79 general practice patients with uncontrolled systolic hypertension participated in a double-blind randomised placebo-controlled dose-response trial of 12 weeks. Participants were allocated to one of three garlic groups with either of one, two or four capsules daily of aged garlic extract (240/480/960 mg containing 0.6/1.2/2.4 mg of S-allylcysteine) or placebo. Blood pressure was assessed at 4, 8 and 12 weeks and compared with baseline using a mixed-model approach. Tolerability was monitored throughout the trial and acceptability was assessed at 12 weeks by questionnaire.

Results: Mean systolic blood pressure was significantly reduced by 11.8±5.4 mm Hg in the garlic-2-capsule group over 12 weeks compared with placebo (P=0.006), and reached borderline significant reduction in the garlic-4-capsule group at 8 weeks (-7.4±4.1 mm Hg, P=0.07). Changes in systolic blood pressure in the garlic-1-capsule group and diastolic blood pressure were not significantly different to placebo. Tolerability, compliance and acceptability were high in all garlic groups (93%) and highest in the groups taking one or two capsules daily.

Conclusions: Our trial suggests aged garlic extract to be an effective and tolerable treatment in uncontrolled hypertension, and may be considered as a safe adjunct treatment to conventional antihypertensive therapy.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antihypertensive Agents / administration & dosage
  • Antihypertensive Agents / adverse effects
  • Antihypertensive Agents / chemistry
  • Antihypertensive Agents / therapeutic use*
  • Capsules
  • Combined Modality Therapy / adverse effects
  • Cysteine / administration & dosage
  • Cysteine / adverse effects
  • Cysteine / analogs & derivatives
  • Cysteine / analysis
  • Cysteine / therapeutic use
  • Dietary Supplements* / adverse effects
  • Dietary Supplements* / analysis
  • Double-Blind Method
  • Female
  • Garlic / chemistry*
  • Humans
  • Hypertension / diet therapy*
  • Hypertension / drug therapy
  • Intention to Treat Analysis
  • Male
  • Middle Aged
  • Patient Compliance
  • Patient Dropouts
  • Plant Extracts / administration & dosage
  • Plant Extracts / adverse effects
  • Plant Extracts / chemistry
  • Plant Extracts / therapeutic use*
  • Plant Roots / chemistry*

Substances

  • Antihypertensive Agents
  • Capsules
  • Plant Extracts
  • S-allylcysteine
  • Cysteine