Garlic put to the test - updates - ConsumerLab.com tests 14 garlic-based dietary supplements

It can help prevent hardening of the arteries, reduce levels of "bad" cholesterol and has even shown promise at fighting colds and cancer. But how good is garlic, really? The news is promising: In 2002, natural products industry watchdogs at ConsumerLab.com tested 14 brands of dietary supplements made from garlic, garlic powder or aged garlic extract, and all but three passed.

From the report, released October 29, 2002: "Not all garlic products are created equal. Good quality, non-aged garlic should yield a minimum of 3,000 micrograms (mcg) of allicin--the active compound in garlic--per gram of dried garlic, or 1,000 meg of allicin per gram of fresh garlic."

Known for its ability to kill bacteria and fungus, allicin has been used in wars to fight infections. A small amount of allicin is present in fresh garlic, but enzymes in the garlic produce more when the cloves are cut or crushed and exposed to water--similar to conditions in the intestines.

The president of ConsumerLab.com, Tod Cooperman, says consumers stand to be confused by garlic supplements with relatively low concentrations of allicin. Of the 11 products that passed ConsumerLab.com's test, one barely managed to meet the minimum standards for garlic quality--but there was so little garlic in the supplement that the daily yield of allicin was demonstrably less than what ConsumerLab.com found to be effective. A supplement containing 400 milligrams (mg) of garlic is less effective than one that contains 400 mg of garlic powder, which is more concentrated.

The majority of supplements tested contained non-aged garlic, with allicin yields ranging from about 400 mcg to 6,500 mcg. One product tested, Kyolic Aged Garlic Extract--manufactured by Wakunaga Consumer Products--contained aged garlic, which does not have garlic's characteristic odor because it does not produce allicin. It does contain compounds similar to allicin, however, and met ConsumerLab.com's requirements.

Although garlic supplements are generally believed to be safe, ConsumberLab.com issued some caveats along with the report:

* After large doses of garlic, side effects can include upset stomach, facial flushing, rapid pulse, dizziness, allergies and insomnia.

* Garlic can thin the blood. To avoid bleeding problems, do not take garlic supplements before undergoing surgery or along with blood-thinning medications and supplements such as ginkgo, policosanol and vitamin E.

* AIDS patients should not use garlic supplements because the supplements can reduce the effectiveness and blood levels of some AIDS drugs.