Garlic consumption is associated with reduced blood pressure. This is supported by several studies. For example, a 2009 meta-analysis of 25 studies by Shari Hensen suggests that garlic supplements lower blood pressure levels better than a placebo. A compound in garlic, allicin, accounts for much of garlic's beneficial effects on blood pressure.
Definition of Hypertension
As per Shari Hensen, hypertension, or high blood pressure, is defined as systolic blood pressure equal to or greater than 140 mm Hg, or millimeters of mercury, and diastolic blood pressure, DBP, equal to or greater than 90 mm Hg.
Garlic Powder Tablets vs. Pills
A 2009 study by Sobenin et al compared the blood-pressure-reducing action of time-released garlic powder tablets to that of regular garlic pills in 84 men with mild or moderate hypertension. The time-released garlic tablets resulted in a reduction of both systolic and diastolic blood pressure. Treatment with garlic pills resulted in the same decrease in systolic blood pressure but no decrease in diastolic blood pressure. The time-released garlic powder tablets are more effective at reducing mild to moderate hypertension than are regular garlic supplements.
Garlic Cloves
A study of 30 patients by Fredi Alicajic that was published in 2009 looked at patients who had taken three cloves, about 10g, of garlic daily during a one-month period. Patients did not take any other antihypertensive medications. In 22 patients, 73.34 percent, the study found a reduction of the average systolic blood pressure for 9.52 percent, and the average diastolic for 10.42 percent.
Allicin
An article by Gilbert Chin in "Science" proposed that the compound allicin--found in garlic--caused nerve cells to release peptides that lead to the dilation of blood vessels, which may explain garlic's effect on blood pressure. In addition, as stated in a 2008 article by Karin Ried et al., garlic may reduce blood pressure due to hydrogen sulfide production and allicin content. Allicin has angiotensin II inhibiting and blood vessel dilating effects.
Contraindications
Karin Ried et al. state that a meta-analysis from 1994 reported optimistic results in people with mild hypertension but did not find enough evidence to recommend garlic for clinical therapy. According to a 2010 article by Catherine Ulbricht , people should avoid garlic if allergic or hypersensitive to garlic or other members of the Lilaceae (lily) family such as hyacinth, tulip, onion, leek or chive, as should those with a history of bleeding problems, asthma, diabetes, low blood pressure or thyroid disorders. She also states that people should stop using garlic supplements two weeks before and immediately after dental or surgical procedures with bleeding risks, and avoid supplemental doses if pregnant or breastfeeding.
References
- "BMC Cardiovascular Disorders"; Effect of garlic on blood pressure: a systematic review and meta-analysis; Ried K, et al.; June 2008
- "Official Journal Of The Japanese Society Of Hypertension"; Time-released garlic powder tablets lower systolic and diastolic blood pressure in men with mild and moderate arterial hypertension; Sobenin IA, et al.; June 2009
- "Materia Socio Medica"; Hypertension and Garlic; Alicajic, Fredi; 2009
- "HerbalGram"; Garlic Preparations Show Benefit in Reducing Blood Pressure; Henson, Shari; Feb-Apr 2009
- "Science"; One Singular Sensation; Chin, Gilbert; September 2005
- "Alternative & Complementary Therapies"; High blood pressure: an integrative approach: a natural standard monograph; Ulbricht C; June 2010
