Karen Reid and colleagues at the University of Adelaide have found that an extract from the humble clove of garlic can help treat hypertension (high blood pressure).
Hypertension (systolic blood pressure [SBP] ≥ 140 mm Hg; diastolic blood pressure [DBP] ≥ 90 mm Hg) is a known risk factor for cardiovascular morbidity and mortality, affecting an estimated 1 billion individuals worldwide. Recently updated guidelines for the treatment of high blood pressure stress the importance of preventive strategies, and recommend extending the management of blood pressure to include pre-hypertensive individuals (SBP 120–139/DBP 80–89 mm Hg). Primary management should include relevant lifestyle modifications such as increased exercise, weight loss and dietary changes which could incorporate dietary supplementation.
The extensive studies were carried out over a time period of twelve weeks and involved fifty test subjects with SBP levels at or above 140. Researchers found that those with systolic blood pressure above 140 who took aged garlic extract capsules experienced an average systolic blood pressure 10.2mmHg lower than the control group, who took a placebo.
"This reduction is clinically significant, as a drop in systolic blood pressure by 5 mmHg reduces the risk of cardiovascular disease by 8-20%," Dr Ried says.
Garlic (Allium sativum) has played an important dietary as well as medicinal role in human history. Blood pressure reducing properties of garlic have been linked to its hydrogen sulphide production  and allicin content – liberated from alliin and the enzyme alliinase – which has angiotensin II inhibiting and vasodilating effects, as shown in animal and human cell studies .
The WHO guidelines for general health promotion for adults is a daily dose of 2 to 5 g of fresh garlic (approximately one clove), 0.4 to 1.2 g of dried garlic powder, 2 to 5 mg of garlic oil, 300 to 1,000 mg of garlic extract, or other formulations that are equal to 2 to 5 mg of allicin.
The research is as important in Australia as in other countries where a large percent of the population suffers from heart disease according to Dr. Reid because up to one in three adults in Australia are hypertensive or suffer from high blood pressure, a leading risk indicator of heart disease. Only half of these people actually receive medication to control their blood pressure and more alarmingly a further half of these patients are not receiving adequate treatments for their condition.
These findings are of great importance world over because the epidemic of heart disease is affecting developing countries as much as developed countries as sedentary lifestyles and unhealthy foods become more widespread. This in conjunction with the high stress lifestyles that most people lead has made high blood pressure a widely prevalent issue that goes largely undetected and therefore untreated.
Ried K, Frank OR, Stocks NP, Fakler P, Sullivan T. Effect of garlic on blood pressure: a systematic review and meta-analysis. BMC Cardiovascular Disorders 2008; 8:13
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