written by Jack Challem, The Nutrition Reporter™ 

Despite the fact that garlic has been in use as both a dietary staple and a medicinal herb for over 3,000 years, its real potential has remained obfuscated to the public at large. Garlic does more than just spice up your food; it has been proven to fight disease, improve the quality of life and in fact extend longevity.

Garlic's Active Ingredients

The core mystery surrounding garlic has been its obscure, intrinsic nature. What makes garlic such a "wonder" herb? A garlic clove, in and of itself, seems plain and nondescript. And there appears to be little if anything taking place on a molecular level. However, once the garlic clove is "damaged" a rapidly ensuing metamorphosis takes place. It is during this sudden change that garlic takes on its true nature. This damaged state, which can come about through slicing, mashing, or chewing, results in the garlic's main enzyme alliinase instantaneously converting alliin (another enzyme) into allicin. And it is this newly created enzyme, allicin, which gives garlic its characteristic smell.

Though allicin was once thought to be garlic's principal active ingredient, researchers now know that allicin has a short life-span and is particularly sensitive to heat and oxidation. Yet, more than 100 biologically active, sulfur-containing compounds, proteins, and saponins are created as a result of oxidation. While allicin may still serve as a general marker of garlic's potency, research increasingly points to S-allylcysteine and other compounds as the most therapeutically active ingredients in garlic.

Garlic Fights Microbial Infections

Scientific research has also confirmed garlic's role as a natural antibiotic. Back in 1983, as noted in Medical Hypotheses, "garlic extract has broad-spectrum antimicrobial activity against many genera of bacteria and fungi...Because many of the microorganisms susceptible to garlic extract are medically significant, garlic holds a promising position as a broad-spectrum therapeutic agent."

One way garlic works is by promoting phagocytosis, the ability of white blood cells to fight infections. Another is by stimulating other immune cells, such as macrophages and T-cells to fight bacterial and viral infections and to scavenge for cancer cells. One report, in Deutsche Zeitschrift für Onkologie, described how garlic enhanced the body's "killer cell" activity against the AIDS virus.

Garlic Benefits the Cardiovascular System

Adesh K. Jain, M.D., of the Clinical Research Center and Tulane University School of Medicine, reported that garlic can lower blood levels of "total" cholesterol and, particularly, of the dangerous low-density lipoprotein (LDL) form. Twenty men and women were given 900 milligrams of garlic powder tablets daily and compared them to twenty-two people getting just a placebo. By the end of the 12-week study, total blood cholesterol levels dropped by an average of 6 percent among those taking garlic tablets, compared with only a 1 percent drop among those taking a placebo. The garlic takers also benefited from an 11 percent decrease in the LDL form of cholesterol, compared with a 3 percent reduction in the placebo group.

Garlic is also an anticoagulant - a natural blood thinner. H. Kieswetter, M.D., of Saarland University, recently found that garlic could help patients suffering from peripheral arterial occlusive disease, characterized by blood clots in the legs. Typically, patients with the condition are asked to walk, because increased blood flow reduces the number of clots. However, they are easily discouraged because peripheral arterial occlusive disease causes extreme pain after walking only a short distance. Thirty-two patients were given 800 milligrams of garlic powder tablets daily for 12 weeks, while another thirty-two patients received a placebo. For the first several weeks, both groups of patients progressed about as they would in a typical walking program. As time went on however, patients taking garlic were able to walk about one-third farther without pain, according to Kieswetter's report in Clinical Investigator.

Garlic Protects Against Cancer

Garlic also protects against cancer. Benjamin Lau, M.D., Ph.D., noted in Molecular Biotherapy, that garlic "is one of the most ancient of plants reputed to have an anticancer effect. As recorded around 1550 B.C., in the Ebers Papyrus, garlic was used externally for the treatment of tumors by ancient Egyptians and internally by Hippocrates and Indian physicians."  Dr. Lau, a researcher at the Loma Linda University School of Medicine, has identified three ways garlic protects against cancer: (1) by directly inhibiting tumor cell metabolism, (2) by preventing the initiation and reproduction of cancer cells, and (3) by boosting a person's immune system to more efficiently fight cancer cells.

John Milner, Ph.D., of Pennsylvania State University, University Park, recently studied how aged garlic powder might protect against nitrosamine-induced cancers in laboratory mice. Nitrosamines are formed when processed meats, such as bacon and bologna are eaten.  Milner found that a diet consisting of 2 to 4 percent garlic delayed the growth of breast cancer and reduced the number of tumors. "The total tumor number was reduced by 56% in rats fed the 2% garlic-powder diet throughout the 20 weeks feeding period compared to control-fed rats," he explained in Carcinogenesis.
In a separate study, Dr. Milner found that garlic could dramatically reduce the number of "adducts" in deoxyribonucleic acid (DNA). Adducts are chemicals that attach nitrosamines to DNA, which act as a catalyst for cancerous changes.  In an experiment, Dr. Milner exposed a group of laboratory rats to nitrosamines, but some of the animals were also given large amounts of aged garlic powder - again, 2 to 4 percent of the diet. Depending on the amount of garlic they ate, the rats had a 40 to 80 percent reduction of adducts in the liver.

The best way to take garlic

So how should you take garlic? Most scientific studies have, for consistency, used a standardized garlic extract in capsule or liquid form. However, many nutritionists would suggest taking garlic in its natural state, raw using a garlic press or some other device that crushes the garlic clove. Nevertheless, just about any form offers some benefits. If you enjoy the taste of garlic, use it liberally in your food. If the taste and odor turn you off, opt for deodorized garlic capsules. Either way, garlic is good for your health.