NEW YORK (Reuters Health) -
Garlic supplements may lower
blood pressure just as effectively as some drugs used to treat
hypertension can, according to a new research review.

“Supplementation with garlic preparations may provide an
acceptable alternative or complementary treatment option for
hypertension,” Dr. Karin Ried and colleagues from The
University of Adelaide in South Australia write.

Research to date on garlic and blood pressure has had
“inconclusive” results, they note, while the last meta-analysis
- in which the results of several studies are analyzed
collectively — only included studies done up until 1994.

To provide an updated perspective, Ried and her team
included more recently published studies in their analysis,
identifying 11 studies in which the patients were randomly
assigned to garlic or placebo. In most studies, participants
given garlic took it in powdered form, as a standardized
supplement. Doses ranged from 600 mg to 900 mg daily, which
study participants took for 12 to 23 weeks.

When the researchers pooled the data from the trials, they
found that garlic reduced systolic blood pressure (the top
number in a blood pressure reading) by 4.6 mm Hg, on average.
An analysis limited to people with high blood pressure showed
garlic reduced systolic blood pressure by 8.4 mm Hg, on
average, and diastolic blood pressure (the bottom number) by
7.3 mm Hg. The higher a person's blood pressure -was at the
beginning of the study, the more it was reduced by taking
garlic.

The effects were similar to those of widely used drugs for
treating hypertension, for example beta blockers, which reduce
systolic blood pressure by 5 mm Hg, and ACE inhibitors, which
produce an 8 mm Hg average drop in systolic blood pressure, the
researchers note.

The 600 mg to 900 mg dosage used in the studies is
equivalent to 3.6 mg to 5.4 mg of garlic's active ingredient,
allicin, Ried and her team point out. A fresh clove of garlic
contains 5 mg to 9 mg of allicin.

In the population as a whole, they note, reducing systolic
blood pressure by an average of 4 to 5 points and diastolic
blood pressure by 2 to 3 points could cut the risk of heart
disease and heart disease-related death by up to 20 percent.

More research is needed to determine whether garlic
supplementation might have a long-term effect on heart disease
risk, the researchers conclude.

SOURCE: BMC Cardiovascular Disorders, published online June
16, 2008.