Garlic, the Surprise Healer

What is Garlic?patients with mild hypertension (Silagy & Neil,
Garlic is a member of the onion (Allium) family, and is1994). The effectiveness of garlic in reducing blood
used in fresh or dries form as a source ofcholesterol and triglyceride levels has been the
characteristic sulphur containing substances (e.g.allicin,subject of debate; however the balance of evidence
which is responsible for the odour of garlic) that havefrom randomized clinical trials suggests that garlic
potentially beneficial effects within the body. Some ofsupplementation is capable of moderate reductions in
these compounds are present in garlic in a latentblood cholesterol and/or triglyceride levels ( Silagy
form, which are activated when garlic cloves are& Neil, 1994; Stevinson et al, 2001; Alder et al,
crushed or digested.2003; Warshafsky et al, 1993).
What does Garlic do?(ii) Cancer: The reputation of garlic as an effective
When garlic is crushed, or digested within thetreatment for malignant tumours extends back to
intestinal tract, the sulphur containing amino acidthe time of the ancient Egyptian civilization, but
derivative alliin is converted by the enzyme allinasescientific support for its therapeutic potential has
(also present in garlic) into allicin, which is the mostbeen obtained only recently. Cell culture, animal model
important of the active substances present in garlic.and epidemiological studies have shown evidence for
The activity of the enzyme allinase is reduced byanticancer activity of garlic extracts or specific
heat, so the potential benefits of garlic are reducedchemical compounds derived from garlic. These
by cooking. The active compounds ingarlic reduce theeffects include the regulation of cell cycle
adhesiveness of blood platelets and have antprogression, the modification of signal transduction
i-thrombotic action, thereby reducing the tendency ofpathways, the stimulation of immune function, and
blood to clot. These active compounds dilate bloodthe regulation of nuclear factors involved in
vessels, thereby reducing blood pressure; they alsoinflammation.
have immune system enhancing effects, as well asA number of case control studies have been
having anti-microbial action against certain types ofreported which demonstrate a protective effect of
pathogenic bacteria. Clinical studies have showngarlic consumption against human cancers; examples
supplementation with garlic to have the followinginclude prostate cancer (Key et al, 1997), breast
benefits:o Garlic inhibits the development ofcancer (Challier et al 1998) and gastric cancer (Kim et
atherosclerosiso Garlic reduces blood cholesterolal, 2002). A meta-analysis of the epidemiological
levelso Garlic reduces high blood pressureo Garlicliterature by Fleischauer et al (2000) demonstrated a
inhibits the development of certain types of cancersprotective effect of garlic against stomach and
What evidence is there for the efficacy of Garlic?colorectal cancers.
(i) Cardiovascular disease: Randomised controlledAre there adverse effects from taking Garlic?
clinical trials have shown supplementation with garlicGarlic is generally well tolerated, with mild
reduced arterial plaque formation inpatients withgastrointestinal disturbance or skin rash being
atherosclerosis (Koscielny et al, 1999), and reducesoccasionally reported. Clinical and animal studies have
the risk of death from heart disease by inhibitingshown the toxicity of garlic to be very low. Garlic
atherosclerosis (Sobenin et al, 2005). A meta-analysismay interfere with the action of anti-coagulant and
of the effect of garlic on blood pressure indicatedanti-hypertensive drugs.
that garlic may be useful in reducing blood pressure in