Parts used and where
grown
Garlic has been used since time
immemorial as a culinary spice and medicinal herb. Garlic has been
cultivated in the Middle East for more than 5,000 years and has been an
important part of Traditional Chinese Medicine. The region with the
largest commercial garlic production is central California. China is also
a supplier of commercial garlic. The bulb is used medicinally.
Historical or traditional use
(may or may not be supported by scientific studies)
Garlic is mentioned in the
Bible and the Talmud. Hippocrates, Galen, Pliny the Elder, and Dioscorides
all mention the use of garlic for many conditions, including parasites,
respiratory problems, poor digestion, and low energy. Its use in China was
first mentioned in A.D. 510. Louis Pasteur studied the antibacterial
action of garlic in 1858.
Active
constituents
The sulfur compound allicin,
produced by crushing or chewing fresh garlic or by taking powdered garlic
products with allicin potential, in turn produces other sulfur compounds:
ajoene, allyl sulfides, and vinyldithiins. Aged garlic products lack
allicin, but may have activity due to the presence of
S-allylcysteine.
Many publications have shown
that garlic supports the cardiovascular system. While earlier trials
suggest it may mildly lower cholesterol and triglyceride levels in the
blood, more recent trials found garlic to have minimal success in lowering
cholesterol and triglycerides. Garlic also inhibits platelet stickiness
(aggregation) and increases fibrinolysis, which results in a slowing of
blood coagulation. It is mildly antihypertensive and has antioxidant
activity.
Garlic’s cardiovascular
protective effects were illustrated in a four-year clinical trial on
people 50–80 years old with atherosclerosis. It was found that consumption
of 900 mg of a standardized garlic supplement reduced arterial plaque
formation by 5–18%. The benefits were most notable in women.
In test tube studies garlic has
been found to have antibacterial, antiviral, and antifungal activity.
However, these actions are less clear in humans and do not suggest that
garlic is a substitute for antibiotics or antifungal medications.
Human population studies
suggest that eating garlic regularly reduces the risk of esophageal,
stomach, and colon cancerThis may be partly due to garlic’s ability to
reduce the formation of carcinogenic compounds.
How much is usually
taken?
People who wish to consume
garlic and have no aversion to its odor can chew from one to two whole
cloves of raw garlic daily. For those who prefer it with less odor,
enteric-coated tablets or capsules with approximately 1.3% allin are
available. Clinical trials have used 600–900 mg (delivering approximately
5,000–6,000 mcg of allicin potential) per day in two or three divided
amounts. Aged-garlic extracts have been studied in amounts ranging from
2.4–7.2 grams per day.
Are there any side effects or
interactions?
Many people enjoy eating
garlic. However, some people who are sensitive to it may experience
heartburn and flatulence. Because of garlic’s anti-clotting properties,
people taking anticoagulant drugs should check with their doctor before
taking garlic. Those scheduled for surgery should inform their surgeon if
they are taking garlic supplements. Garlic appears to be safe during
pregnancy and breast-feeding. In fact, two studies have shown that babies
like breast milk better from mothers who eat garlic.
Are there any drug
interactions?
Certain medicines may interact with garlic.