Encyclopedia of Health and Medicine

G
garlic In ancient times people used garlic to
ward off the evil vapors and spirits they believed
responsible for illness. In modern times doctors
know more about what really causes many of the
health circumstances that result in disease. People
use garlic and garlic supplements to improve
BLOOD circulation, lower BLOOD PRESSURE, and
reduce blood cholesterol, the key factors that contribute
to CARDIOVASCULAR DISEASE (CVD). The active
ingredients in garlic (Allium sativum) are allium
compounds (also found in onions and leeks), sulfur-based
substances that give garlic its distinctive
odor and flavor as well as its medicinal benefits.
More than 100 clinical research studies point to
allium compounds as the substances responsible
for these benefits. Allium compounds contain two
dozen or so chemicals that
• reduce PLATELET AGGREGATION, making it more
difficult for the blood cells that initiate the clotting
process to stick together
• help maintain the FLEXIBILITY of ARTERY walls
• may block cholesterol production in the LIVER,
reducing the blood levels in particular of the
low density lipoprotein (LDL) and very low
density lipoprotein (VLDL) cholesterols associated
with ATHEROSCLEROSIS and CORONARY ARTERY
DISEASE (CAD)
• have mild anti-inflammatory effects, helping
reduce irritation and INFLAMMATION of the inner
walls of the arteries that researchers believe sets
the stage for arterial plaque accumulations that
form the basis of atherosclerosis and CAD
• have mild antibacterial effects that improve
resistance to infections affecting the MOUTH and
THROAT
These effects seem the same whether the
source of the garlic is the natural bulb or supplements.
Some studies show as much as a 6 to 10
milligram per deciliter (mg/dL) reduction in total
blood cholesterol levels after taking garlic supplements
for three months, about the same result
doctors expect to see with lipid-lowering medication
therapy. The combined effect of garlic’s
actions on the cardiovascular system help lower
blood pressure by decreasing the resistance blood
encounters as it flows through the arteries.
Though the preventive benefit for HEART ATTACK
and STROKE is difficult to measure, many health
experts agree that the many effects of garlic, however
small, add up to reduced risk for cardiovascular
disease, especially in combination with other
lifestyle factors such as regular daily exercise,
weight loss, and SMOKING CESSATION. Some health
experts believe garlic and garlic supplements also
lower the risk for DIABETES type 2 by improving
INSULIN sensitivity, though clinical studies so far
have failed to bear this out. Nor is there much evidence
supporting garlic’s ability to reduce CANCER
risk.
Garlic and garlic supplements are relatively safe
for most people to take, though may intensify the
effect of many common antihypertensive medications.
People who are taking medications to treat
high blood pressure should first talk with their
doctors before beginning a garlic regimen. The
amounts of garlic a person might use in seasoning
foods are not enough to cause this interference,
though the amounts of garlic in therapeutic products
can interact with numerous medications.
Because garlic affects clotting, surgeons generally
request people stop taking it before any scheduled
operations.
69