Standardized Garlic Powder Reduces Heart Attack Risk
A study published in the May issue of Atherosclerosis
showed that a garlic powder supplement (Allium sativum
L., Liliaceae) can help prevent and, in some cases, even reverse
plaque build-up in the arteries (Koscielny et al., 1999).
Researchers have long associated arterial plaque with an increased
risk of heart attack and stroke. The study was conducted using
rigorous controls (randomized, double-blind, placebo-controlled)
and took place over a four-year period, making it the longest
clinical trial to evaluate the effects of a dietary supplement
on reducing heart attack risk.
For the four-year study, 152 men and women were randomly assigned
to take either placebo or 900 mg of standardized garlic powder
daily (Kwai®, Lichtwer Pharma, Berlin). From the beginning,
all participants had advanced plaque accumulation, in addition
to at least one other established risk factor for heart disease,
such as high cholesterol or blood pressure, diabetes, or a history
of smoking. Researchers used B-mode ultrasound to measure the
progression and regression of plaque volume in the common carotid
and femoral arteries, at the beginning of the study and at 16,
36, and 48 months.
At the end of the study, those who took garlic had a 2.6 percent
reduction in plaque volume, compared to a 15.6 percent increase
in the placebo group. When the effects were analyzed by gender,
there was a 4.4 percent decrease in plaque volume in men taking
garlic, compared to a 5.5 percent increase in the male placebo
group. The results for women initially took researchers by surprise.
While women in the garlic group experienced a modest 4.6 percent
decrease in plaque volume, those taking placebo had a massive
53.1 percent increase.
According to the researchers, the striking difference between
the two female groups was due to a predominance of younger women
in the placebo group, and more older women in the garlic group
by the end of the study. Although the age distribution was relatively
even at the beginning of the study, it became unbalanced as a
greater number of younger women in the garlic group withdrew from
the study, mostly due to "annoyance by odor." Unfortunately, this
prevented the researchers from drawing meaningful conclusions
about garlic based on the age composition of the study groups.
Clearly, the double-blind design of the study was also defeated
by the odor of the garlic pills, which were easily distinguished
from the placebo pills. However, the investigators asserted that
the 4.6 percent decline in plaque volume observed in women taking
garlic remains a "genuine garlic effect."
Based on this study and more than 20 others conducted on standardized
powdered garlic, researchers believe that garlic can have not
only a preventative but also a curative role in heart disease.
Previous studies demonstrate that powdered garlic reduces total
and harmful LDL cholesterol levels, serum triglycerides, and blood
pressure, and also inhibits cholesterol oxidation and platelet
aggregation (the tendency of the blood platelets to clump), among
other positive effects. This study adds more support to the scientific
case for garlic as a "pleiotropic" substance, meaning that garlic's
mild effects on many different measurements of heart health add
up to significant overall benefits. - Krista Morien
[Koscielny J, Klüssendorf
D, Latza R, Schmitt R, Radtke H, Siegel G, Kiesewetter H. The antiatherosclerotic
effect of Allium sativum. Atherosclerosis 1999; 144: 237-249.]