Garlic long has been revered as a special food, not just for the unique flavor it imparts to foods but for its medicinal value. There is evidence that Egyptians worshiped garlic, having placed clay models of the bulb in Tutankhamen’s tomb. It is said that Hippocrates himself used garlic vapors to treat certain cancers. In 1858, Louis Pasteur noted that bacteria died when doused with garlic. And during World War II, British physicians treated battle wounds with garlic preparations when antibiotics were scarce.
Although these remedies sound like folklore, modern science provides evidence to back up garlic’s claim to fame. Garlic, as well as onions, leeks, chives and shallots, belong to a family of plants called allium. Vegetables and herbs in the allium family contain sulfur compounds that give them their pungent flavors and fragrances. Recent studies suggest these substances, particularly diallyl sulfide, S-allyl cysteine and allicin, may be potent inhibitors of the cancer initiation process, especially for colorectal and stomach cancers.
Garlic also has been widely studied for its role in cardiovascular health. Dioscorides, a well-known physician from the first century, wrote that garlic "clears the arteries and opens the mouths of veins." Recent studies that have examined the effects of garlic on blood cholesterol have shown mixed results. Some studies have shown a reduction in LDL cholesterol, or bad cholesterol levels, while others have not. However, if garlic does indeed have cardio-protective properties, it may be traced – at least in part -to its proposed ability to reduce the formation of blood clots, a claim that is gaining research attention of its own.
Garlic has been studied for immune-boosting properties, further solidifying its place in the medicinal plant hall of fame. Numerous studies performed in recent years indicate that the compound allicin, found in fresh garlic, has antibiotic and antifungal properties.
The chemical composition of garlic changes in response to being heated and even chopped, but nobody is quite sure which form delivers the most punch. For example, allicin is released when fresh garlic is chopped or pressed but destroyed with heating. It is for this reason that capsules, which contain processed garlic, may not be as effective as the real thing.
When selecting fresh garlic, look for firm, large-cloved bulbs in which the outer skin is tight, unbroken and free of soft spots. Store fresh garlic in a cool, dry place that allows good air circulation. A mesh bag or specially designed, covered terra-cotta jar with holes in the sides works well. Avoid storing garlic in plastic bags or sealed containers as this tends to cause the garlic to whither and rot. Properly stored, most garlic bulbs can last for up to six months at cool room temperatures.
While it is not necessary to keep fresh garlic in the refrigerator, if you make dressings, oils, butters or marinades containing garlic, be sure to keep these refrigerated and use within two to three weeks. Garlic and oil mixtures stored at room temperature can support the growth of Clostridium botulinum, and subsequent production of a deadly toxin.