Two capsules per day – or 480 mg – of the aged garlic extract for 12 weeks were associated with significant reductions in systolic blood pressure of about 12 mgHg, according to findings published in the European Journal of Clinical Nutrition.
“The observed reduction in systolic blood pressure is comparable to that achieved with commonly prescribed antihypertensive medicines, and is of clinical significance, whereby a reduction of about 10mmHg in systolic blood pressure is associated with a risk reduction in cardiovascular disease by 16–40%,” wrote researchers from the University of Adelaide and the National Institute of Integrative Medicine, Melbourne.
Garlic and heart health
The study adds to the large body of science supporting the cardiovascular benefits of garlic. A recent meta-analysis, published in the Journal of the Science of Food and Agriculture (doi: 10.1002/jsfa.5557), concluded that garlic may also reduce cholesterol and triglyceride levels.
Researchers from Shandong University reported that, compared with placebo groups, garlic consumption is associated with a 5.4% reduction in cholesterol levels and a 6.5% reduction in triglyceride levels.
Garlic (Allium sativum) has been suggested to exhibit several health benefits, including inhibiting enzymes involved in lipid synthesis, decreasing platelet aggregation, preventing lipid peroxidation, and increasing antioxidant status.
The Australian researchers performed a dose–response, tolerability and acceptability trial of aged garlic extract (240/480/960 mg per day, High Potency Everyday Formula 112; Wakunaga/Wagner, Sydney) in 79 patients with uncontrolled hypertension. The patients continued to take their existing antihypertensive medication. The low, medium, and higher dose groups consumed the equivalent of 0.6, 1.2, and 2.4mg of S-allylcysteine per day, respectively, from the supplements.
After 12 weeks of supplementation, the researchers found that the middle dosage group benefited the most, with an average reduction in systolic blood pressure of 11.8 mmHg, compared with placebo.
In the highest dose group, a ‘borderline significant reduction’ of 7.4 mmHg was observed after 8 weeks, they added.
“The smaller reduction in systolic blood pressure in the garlic-4 group compared with the garlic-2 group may have been linked to the poorer compliance and lesser tolerability seen in the garlic-4 group,” they said.
“Larger trials are required to explore any effect of other antihypertensive medicines that patients are already taking on the effectiveness of adjunct therapy with aged garlic extract. It would also be interesting to explore the effect of aged garlic extract on other cardiovascular risk factors and the influence of standard drug therapy on its effectiveness.
“Moreover, long-term trials would provide insights into the effect of aged garlic extract on cardiovascular morbidity and mortality,” they concluded.
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2012.178
“Aged garlic extract reduces blood pressure in hypertensives: a dose–response trial”
Authors: K Ried, O R Frank and N P Stocks