Garlic
Garlic, or Allium sativum, has been cultivated for thousands of years for its therapeutic benefits. Garlic was used as a treatment for tumors, headaches, weakness and fatigue, wounds, sores and infections. It was regarded as a physically enhancing tonic, and was used by the first Olympic athletes as an energizer. The active ingredient is allicin.
Claimed health benefits
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Reduces high blood pressure
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Reduces plasma LDL-cholesterol levels
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Alleviates blood clotting disorders and athersclerosis
Evidence for health benefits
A major study examined the effect of aged garlic extract (AGE) compared to a placebo on blood fat and cholesterol levels. Fifty-six men with slightly elevated cholesterol were given either AGE or a placebo capsules for 6 months. Then for an additional 4 months the men "crossed over" to the opposite treatment. When the men were taking AGE they experienced significant reductions in blood pressure and low-density lipoprotein cholesterol (LDL-C or the "bad" cholesterol") in the blood [1]. This study was well designed and conducted, and the results have been confirmed in several subsequent studies.
An investigation by a team of Dutch scientists examined the methodologies of 18 controlled trials of the effects of garlic. The 18 studies examined not only garlic's effects on blood cholesterol, but also its effect on the inhibition of platelet aggregation (reducing the possibility of clot formation in the blood vessels). The results showed positive effects of garlic although very high doses were needed--the equivalent of 5 - 20 average sized garlic cloves per day [2].
Cautions
The large doses of garlic required for its therapeutic effects have been associated with heartburn, flatulence, gastrointestinal problems and halitosis.
Due to garlic's ability to reduce blood-clotting time, it should not be taken with aspirin, anticoagulants such as coumadin or heparin or other blood-thinning botanicals such as Ginkgo biloba, bilberry or cayenne. This could result in internal bleeding.
It is important to remember that dietary supplements do not have to be manufactured to any standards, and thus supplements from different manufacturers are likely to vary in quality. [tell me more]
There is a distinct lack of scientific data on the safety of herbal supplements when taken by children and pregnant or breast feeding women. If you fit into these categories do not take herbal supplements.
As with all dietary supplements, make sure that you inform your physician of what you are taking when you visit.
Dose
At least one clove of raw garlic is required per day to provide 5,000 micrograms of allicin, the active ingredient. A garlic powder or capsule containing about the same amount of allicin can also be used [3].
Choosing the brand
The principle active agent in garlic is allicin. When garlic cloves are cut or bruised (like when chewed), an amino acid in the garlic oil called alliin is converted to the pungent-smelling allicin by the action of an enzyme.
Read the label to learn the allicin content of the capsules.
Contamination
The people who harvest herbs for these products are not qualified botanists and there have been many reports of unwanted and sometimes poisonous parts of the plants or other plants being picked and added to herbal remedies. Some journals have speculated that liver damage of unknown origin might stem from herbs more often than doctors realize, and a representative for the Centers for Disease Control and Prevention even suggested that some herbal supplements may be contaminated with real drugs for extra "punch".
Cost per month
$6.90 (based on prices in a Midwestern U.S. city, March 2000)
NOTE: No allicin content was listed on any of the brands we surveyed, so actual value for the $6.90/month is uncertain.
For more information go to http://www.botanical.com/botanical/article/garlic.html
References
1.Steiner M, Khan AH, Holberg D, et al: A double-blind crossover study in moderately hypercholesterolemic men that compares the effect of aged garlic extract and placebo administration on blood lipids. AM J Clin Nutr 64:866-870, 1996.
2. Tyler VE: Cardiovascular system problems, in herbs of choice: The Therapeutic Use of Phytomedicinals. New York, Pharmaceutical Products Press, 1993, pp 104 - 109.
3. Foster S: Herbal medicine: An introduction for pharmacists. NARD J 10:127-144, 1996.