No other medicinal herb is more universally recognized and consumed by people worldwide than garlic. It is valued in every major culture in the world as a food, condiment, culinary herb, and botanical medicine. Garlic has been part of the human experience for so long that it’s considered a cultigen, meaning that the plant is known only in cultivation, not in the wild. The original herb may have come from the high plains of a west-central Asian desert, but it evolved to its current form under the husbandry of humans.
For at least 5,000 years, since the time of the Egyptian pharaohs and even before the earliest Chinese dynasties, people have used garlic as medicine. In central Europe in ancient and medieval times, peasants wore necklaces of garlic cloves to keep away vampires and other evils. It is used in China as a preventive for colds and a folk remedy for dysentery. It is even administered as a juice in enemas to kill intestinal parasites.
"I find it fascinating that people have been aware of garlic’s medicinal properties for thousands of years," says William Page-Echols, D.O., an assistant clinical professor of family medicine who teaches alternative medicine at the Michigan State University College of Osteopathic Medicine in East Lansing. "People weren’t just using it in flights of fancy. They knew it was beneficial."
The Taste of Medicine
In the last few decades, more than 1,000 scientific papers have been published on garlic and related herbs of the Allium family. These studies provide strong—although not conclusive—scientific evidence that garlic has extraordinary medicinal powers.
Garlic seems to reduce blood pressure and cholesterol levels, dilate blood vessels, and thin the blood, all of which lowers the risk of heart attack and stroke. It’s believed to kill harmful bacteria in the stomach and protect against gastric cancer. It appears to be a potent antioxidant and may boost the response of your immune system. It also works as an anti-inflammatory.
"When you think about the health problems that most people suffer from today, such as heart disease, cancer, and pain, they usually have as a component some type of inflammation," says Alison Lee, M.D., a pain-management specialist and medical director of Barefoot Doctors, an alternative medicine practice in Ann Arbor, Michigan.
Across cultures, garlic has been used to treat colds, flu, sore throats, high cholesterol, high blood pressure, atherosclerosis (hardening of the arteries), digestive disorders, bladder infections, and liver and gallbladder problems.
"Garlic is an inexpensive, easy-to-obtain medicine," says Dr. Page-Echols. "You can incorporate it into your diet and get its benefits through food. Or, if you don’t like the taste or odor of garlic, you can take it as a supplement."
A Healing Burn
The stinking rose, as garlic was called by the Greeks and Romans, is a member of the genus Allium, which also includes onions, leeks, shallots, and chives. Allium, the ancient Latin name for garlic, is believed to come from an ancient Celtic word—all, meaning "hot" or "burning."
SUPPLEMENTSNAPSHOT
| Garlic Botanical name: Allium sativum. May help: Heart disease, stomach cancer, high blood pressure, infections, colds and flu, sore throat, chronic fatigue syndrome, high cholesterol, atherosclerosis, digestive disorders, diarrhea, bladder infections, liver problems, and gallbladder problems. Special instructions: Try to get your quota of garlic in food, as it may be more easily absorbed into your system. Origin: May have originated in a west-central Asian desert; most garlic used today comes from widely cultivated modern hybrids. Cautions and possible side effects: Don’t use garlic supplements if you’re taking anticoagulants (blood thinners) or hypoglycemics (a type of diabetes drug). Do not take if breastfeeding. Rarely, may cause allergic reactions. |
The volatile oil of garlic gives the herb its distinctive smell and taste. The oil contains more than 30 sulfur compounds, including allicin and a number of others that are biologically active.
The most important of these is allicin, which is produced only when you crush, bruise, or cut a garlic clove. As the membranes of the garlic cells break down, alliin, a sulfur-containing amino acid, comes into contact with an enzyme called allinase. The resulting chemical reaction produces allicin, a pungent and strongly antibiotic compound.
Allicin is highly unstable and quickly degrades into a number of other chemical compounds. Some of these have therapeutic properties, but exactly how they work in the body as medicines has not been determined. Since the process begins with the formation of allicin, researchers believe the allicin content of garlic is the best indication of its medicinal value.
Killing Bad Bacteria
Louis Pasteur, who invented the process of milk pasteurization and developed the germ theory of disease, first demonstrated back in 1858 that allicin is a strong antibacterial. Before the advent of modern antibiotics in the 1930s, cuts and abrasions were treated by expressing garlic juice into a wound. On the Russian front in World War II, the Soviet army relied on garlic to treat the wounded when penicillin and sulfa drugs weren’t available.
This proven antibacterial action may have profound implications in the prevention of one of the world’s most commonly fatal cancers: stomach cancer.
Scientists have found that Helicobacter pylori, a type of bacteria sometimes found in the stomach, appears to be involved in the development of stomach cancer and peptic ulcers, says Jonathan Sporn, M.D., an oncologist and associate professor of medicine at the University of Connecticut Health Center in Farmington. There may be other factors as well, but the link to H. pylori is strong.
"We’re not sure where these bacteria come from, but they’re probably very common in the environment," explains Dr. Sporn. In fact, H. pylori infects half of the people on the planet and up to 90 percent of the populations of some developing countries.
In cultures with diets high in allium vegetables such as garlic and onions, the risk of stomach cancer is low, says Dr. Sporn. And in laboratory tests conducted at the Fred Hutchinson Cancer Research Center and University of Washington Medical Center in Seattle, scientists were able to kill H. pylori using a garlic extract. This study and others have found that garlic is toxic to many "bad" bacterial strains, even some that resist standard antibiotic treatment.
"It’s very provocative evidence, and it fits with the folk wisdom surrounding the use of garlic," says Dr. Sporn. "These studies suggest that there may be something very valuable in garlic."
According to studies in India, garlic may actually benefit the good bacteria in the intestine, thereby improving digestion and enhancing the absorption of minerals. It has been used to re-establish good bacteria in the gut after an infection or antibiotic treatment.
Does all this mean that you should be eating garlic or taking garlic supplements every day? Perhaps, says Dr. Sporn. But how much? And how often? "That’s the problem," he adds. "Although we have evidence that garlic may be preventive against cancer, we don’t have enough information yet to make any specific recommendations."
Have a Heart for Garlic
Garlic may prevent two other major killers, heart disease and stroke, says Dr. Page-Echols. According to several studies, if you make garlic part of your diet or if you take it as a supplement, you may lower your risk of heart disease and atherosclerosis.
When fatty plaque builds up in arteries, blood flow to the heart and brain may be impeded. Clots can form, or chunks of plaque may break loose and form blockages. That sets the stage for a heart attack or stroke.
Garlic benefits the circulatory system in several ways. It lowers levels of cholesterol and triglycerides, another type of blood fat. It also has an antispasmodic action, meaning that it dilates blood vessels and increases blood flow to the heart and brain.
One especially important group of chemicals, called ajoenes, thin the blood and make clotting less likely. So even if you have plaque-filled arteries, the blood platelets are less likely to bunch up behind blockages. Essentially, they slide by a little more easily, says Dr. Page-Echols.
"Garlic can do a lot for your circulatory system. Just keeping the blood vessels more open can have a significant effect on hypertension. Your blood pressure drops," he says.
One study found that after just four weeks of taking garlic supplements, participants had a 5 to 6 percent reduction in total cholesterol. In another study, researchers at the University of California, Irvine, gave 40 men with elevated cholesterol levels either a combination garlic/fish-oil supplement or a look-alike, inactive capsule (placebo). During the study, the men maintained their normal, Western-style diets and kept up their usual activities.
After four weeks, cholesterol levels in the group taking supplements dropped by 11 percent. The placebo group showed no significant change. The researchers concluded that the combination of garlic and fish oil significantly reduces risk potential in people with elevated levels of cholesterol.
"The good thing is that garlic doesn’t tamper with the good cholesterol, only the bad stuff," observes Dr. Page-Echols. "And for someone who wants to do a natural approach to taking care of their heart—in addition to better diet and more exercise—garlic can be very beneficial."
Spice Up Your Immune System
At least one component of garlic, alliin, is also an antioxidant. Some nutrients, such as selenium, vitamin C, vitamin E, and in particular alliin, scavenge free radicals, the free-roaming, unstable molecules that lead to cell damage and premature aging. Free radicals have also been implicated in the growth of tumors. In laboratory animals, garlic extracts have actually inhibited the growth of cancer cells.
Garlic is effective against bacterial, fungal, viral, and parasitic infections. The volatile oil is excreted by way of the lungs—hence garlic breath—and can fight infections in the upper airway. Some Chinese studies have shown that garlic has a beneficial effect in helping to battle colds and flu.
Because of garlic’s antibacterial properties, it can help prevent secondary infections in people who have lowered immunity. An American study in 1989 found that protective natural killer cell activity was restored in some AIDS patients after they took garlic supplements for six weeks.
A Pill Will Do You
You don’t have to eat garlic to get the medicinal benefits. If you find the flavor repulsive or you don’t want to walk around all day with dragon breath, you can take powdered supplements, which are widely available in health food stores and drugstores.
"I prefer that people take garlic in their food because I think it is more easily absorbed into the system. The truth is, however, that most patients can’t get raw garlic down because of the taste," Dr. Lee says. "In that case, taking a garlic supplement is appropriate."
Supplements are available as tablets, capsules, and tinctures. Although oil-based garlic preparations are widely available, their effectiveness is questionable, since allicin is unstable in oil. Moreover, since allicin is formed only when the cells of garlic are crushed to create the enzyme reaction, dried garlic doesn’t contain this important component.
Dried garlic does contain alliin and alliinase, the enzyme that converts alliin to allicin. Look for enteric-coated tablets or capsules, which are designed to pass through the stomach and degrade in the alkaline environment of the intestine, where the beneficial conversion takes place. You’ll get the medicinal benefits without the odor or taste.
