Garlic (Allium sativa), is a plant with long, flat grasslike leaves and a papery hood around the flowers. The greenish white or pink flowers are found grouped together at the end of a long stalk. The stalk rises directly from the flower bulb, which is the part of the plant used as food and medicine. The bulb is made up of many smaller bulbs covered with a papery skin known as cloves. Although garlic is known as the "stinking rose" it is actually a member of the lily family.
The most active components of fresh garlic are an amino acid called alliin and an enzyme called allinase. When a clove of garlic is chewed, chopped, bruised, or cut, these compounds mix to form allicin, which is responsible for garlic's strong smell. Allicin, in turn, breaks down into other sulfur compounds within a few hours. These compounds have a variety of overlapping healing properties.
Garlic also contains a wide range of trace minerals. These include copper, iron, zinc, magnesium, germanium, and selenium. The integrity of the growers and suppliers of garlic are important to the integrity of the garlic used. A soil rich with the presence of trace minerals will produce a healthful bulb of garlic, full of those minerals. Depleted soils produce a depleted product. In addition, garlic contains many sulfur compounds, vitamins A and C, and various amino acids.
The ancient Indians, Chinese, Egyptians, Greeks, Romans, and other peoples have used garlic for thousands of years, as food and as medicine. One of the most famed usages of garlic was during the Middle Ages, when it was reputed to have been highly effective against the plague.
Garlic can be used in the treatment of a variety of bacterial, viral, and fungal infections. It has been shown to be effective against staph, strep, E. coli, Salmonella, Vibrio cholera, H. pylori, Candida albicans, and other microorganisms. Garlic also helps prevent against heart disease and strokes. Current studies show that garlic can improve immune function and may even help in the prevention of cancer. To be of benefit in chronic conditions, garlic should be used daily over an extended period of time.
One of the main causes of heart disease is the buildup of plaque on the walls of the blood vessels. This plaque is mostly made up of cholesterol and other fatty substances found in the blood. When large amounts of plaque get stuck on artery walls, they block the flow of blood and cause blood clots to form. Parts of the artery wall may even be destroyed completely.
In arteriosclerosis, otherwise known as "hardening of the arteries," the major arteries may become so stiff and clogged, that the heart cannot get necessary nutrients and oxygen. This usually causes a heart attack. High serum cholesterol levels are a major risk factor for having a heart attack.
Studies show that people who eat garlic regularly have improved serum cholesterol levels. Some people
Hypertension, or high blood pressure, is also a significant cause of heart problems. It is one of the leading causes of disability and death due to stroke, heart attack, heart failure, and kidney failure. Garlic can help reduce blood pressure through the actions of its sulfur compounds and its ability to reduce the fatty substances, such as cholesterol, found in the bloodstream. Use of garlic also can help normalize low blood pressure.
Platelets clot the blood in order to repair breaks in the blood vessel walls. When there is an injury, platelets are attracted to the damaged area and become attached to the wall and to other platelets. Platelet aggregation, as this process is called, plugs up the break and prevents further blood loss while the injury is being repaired. This is a good and necessary part of healing an injury.
However, if there are serious problems with the heart and blood vessels and there is too much injury and clotting, the vessels may become clogged with platelets. This can lead to strokes and heart disease. The sulfur compounds in garlic—particularly ajoene—give the platelets a slippery quality. They are less able to clump together, thus slowing down platelet aggregation. Garlic can be used effectively in the same way as a daily dose of aspirin to reduce or prevent platelet aggregation over an extended time.
Studies have found that garlic blocks the formation of powerful carcinogens, called nitrosamines, which may be formed during the digestion of food. This may be why in populations where people consume a large amount of garlic, there is a decreased incidence of all types of cancer. The antioxidants found in garlic may also contribute to this effect by protecting against the cell damage by cancer-causing free radicals. Studies show that use of garlic may also inhibit the growth of a variety of tumors. However, cancer-related studies are not conclusive and relate to consumption of raw or cooked garlic, not garlic supplements.
Eating garlic is good for helping the body's immune system resist infections. While garlic is not as strong as modern antibiotics, it is believed to kill some strains of bacteria that have become resistant to antibiotics. Studies have shown garlic treats yeast infections, and it can kill many of the viruses responsible for colds and flu. While daily consumption of garlic was once highly recommended for HIV-positive individuals, the National Institutes of Health (NIH) reported in 2002 that garlic supplements greatly reduced levels of saquinavir, an HIV protease inhibitor, in patients' blood. The NIH began cautioning patients who used garlic to control cholesterol levels who also used saquinavir or combination therapies, since garlic might interfere with their effectiveness.
Modern doctors have been reconsidering the causes of many diseases. They have discovered that bacteria and viruses may be the cause of sicknesses that were formerly not thought to be caused by infections. This includes gastric ulcers, colitis, and Kaposi's sarcoma. Garlic may be useful in treating or preventing these due to its antimicrobial properties.
Garlic has the ability to lower and help keep blood sugar stable by helping to increase the amount of insulin available in the bloodstream. This action, together with garlic's ability to lower cholesterol and blood pressure, make it an excellent daily supplement for people with diabetes. A 2003 report showed that long-term use of garlic helped improve the blood vessel systems of diabetic rats.
Other health conditions
Garlic is effective in the treatment of numerous other conditions. For example:
- The consumption of 1–3 cloves per day is useful for immune support and as a preventive against diseases and infection.
- Warmed garlic oil in the ear canal can be used to treat ear infections.
- Garlic can be used to treat respiratory complaints such as asthma and chronic bronchitis.
- Garlic helps increase the body's ability to handle the digestion of meat and fats.
- Garlic can be used to help kill and expel intestinal worms in both animals and humans.
- When added to a pet's food, garlic helps repel fleas.
- Garlic is helpful in getting rid of athlete's foot.
- Garlic relieves gas and other stomach complaints.
- The sulfur compounds found in garlic can bind to heavy metals and other toxins and help remove them from the body.
- Garlic can be used externally for cuts, wounds, and skin eruptions.
- The taste of garlic in mother's milk stimulates improved nursing. Infants eat more and nurse longer. They appear to relish the taste of slightly garlicky milk. The components of garlic that reach the infant through the mother's milk also may be helpful in relieving colic and infections.
Garlic can be eaten raw or cooked, taken as tablets or capsules, and used as a tincture or syrup. The raw cloves can be directly applied externally.
The suggested dosage for fresh whole garlic is one to three cloves per day. The cloves can be chewed and held in the mouth or swallowed. Consuming raw garlic can actually be a pleasure if the herb is crushed or grated and mixed with food or a tablespoon of honey. The dosage for tinctures is 2–4 ml or 15–40 drops taken twice daily. One tablespoon of the syrup should be taken three times a day, or as needed to relieve coughing. Garlic oil should be slightly warmed, and 1–3 drops should be put in the affected ear 1–3 times per day.
Tablets and capsules are often more convenient to use than raw garlic, and they are more likely to be tolerated by garlic-sensitive individuals. Garlic pills also minimize the garlic taste and odor. Manufacturers vary on which components of the herb are emphasized.
In general, the following dosages are appropriate, but product labels also should be consulted:
- 400–500 mg of allicin, twice daily
- a dose equaling approximately 4,000 mcg of allicin potential, once or twice daily
- 400–1,200 mg of dried garlic powder
- 1,000–7,200 mg of aged garlic
- a dose equivalent to 0.03–0.12 ml of garlic oil, three times per day
Manufactured garlic pills come in a variety of forms, and a great deal of controversy continues about what type is best. Studying the manufacturers' literature and other information is important to make a good decision about which preparation to use. The types of garlic preparations include:
- garlic oil capsules
- encapsulated powdered garlic
- odorless garlic pills
- allicin-stabilized pills
- aged garlic extract
A poultice can be made using grated or crushed fresh garlic. The herb material should be placed directly on the site of injury or eruption, either "as is" or mixed with enough honey to make a paste. The poultice can be held in place with a cloth or bandage.
A compress of garlic is less messy than a poultice and may be less irritating to the site of the injury. It is made by wrapping grated or crushed fresh garlic in a single piece of cheesecloth. As with the poultice, the compress is placed directly on the affected area.
Garlic oil can be made by putting a whole bulb of grated or finely chopped garlic into a pint jar of olive oil, and letting it sit undisturbed in a warm place, away from direct sunlight, for at least two weeks. Then it can be strained and refrigerated. The garlic oil will stay fresh in the refrigerator for up to two years.
A garlic suppository can be used to treat vaginal yeast or mild bacterial infections. A clove of fresh garlic should be peeled and slightly crushed or bruised. If crushed garlic irritates the vaginal tissue, an alternative that might lessen the desired antimicrobial effect is to use the whole, uncrushed garlic clove. The clove should be wrapped in a single layer of cheesecloth and inserted into the vaginal canal overnight for 5-10 days. Dental floss or a length of the cheesecloth can be used to make the suppository easier to retrieve. If the garlic causes a burning sensation, this can be eased with the insertion of plain yogurt into the vagina.
Consumers will find a wide variety of garlic preparations on the market. Therefore, it is important to study manufacturers' claims, talk to knowledgeable practitioners, and find out which formulations are most effective for a given condition.
Due to the high concentration of sulfur compounds in garlic, it should be avoided by those allergic to sulfur. Garlic
Raw garlic can be very irritating to the digestive system. Excessive intake (usually, more than three or four cloves a day) can cause bloating, gas, cramping, diarrhea, and may even damage the red blood cells. When applied to the skin, garlic may cause itching, redness and swelling. Garlic that is cooked, aged, or made into pills is not nearly as harsh on the system. However, these forms may not be as suitable as raw garlic in treating some conditions, particularly infections.
Garlic travels through the lungs and the bloodstream, giving a pungent garlic odor to the breath, skin, and perspiration. The odor will be present for at least 4–18 hours, sometimes even when so-called odorless garlic pills are used.
- —A buildup of fats, cholesterol, calcium, and fibrous tissue in the blood that tends to attach to and weaken artery walls.
Garlic does well when combined with coltsfoot or lobelia for treating asthma and bronchitis. Although onion is not as potent as garlic, it has similar actions, and the two often are combined. Use of garlic is contraindicated in individuals using the anticoagulant drug warfarin or certain HIV therapies.
Green, James The Male Herbal. Freedom, CA: The Crossing Press, 1991.
Murray, N.D., Michael T. The Healing Power of Herbs: The Enlightened Person's Guide to the Wonders of Medicinal Plants. Roseville, CA: Prima Publishing, 1992, 1995.
Romm, Aviva Jill. Natural Healing for Babies and Children. Freedom, CA: The Crossing Press, 1996.
Weed, Susun. Menopausal Years: The Wise Woman Way, Alternative Approaches for Women. Woodstock, NY: Ash Tree Publishing, 2000.
Gangel, Elaine Kierl. "Garlic Supplements and HIV Medication." American Family Physician (March 15, 2002):1225.
"Garlic Attenuates Time-dependent Changes in Reactivity of Isolated Aorta." Cardiovascular Week (October 27, 2003):8.
Novick, Jeff. "Garlic and Cancer." Health Science 25, no. 1 (Winter 2002):6.
"UCLA Researchers Find Garlic Has Ability to Reduce Heart Disease Risk Factors." Townsend Letter for Doctors and Patients (July 2003):22.
"Garlic." Herb Directory by Name. http://www.holisticonline.com/w_holisticonline.htm
"Garlic and Cancer Prevention." http://www.mayohealth.org/mayo/askdiet/htm/new/qd000223.htm
"Garlic's Breath of Health." http://www.usaweekend.com/health/carper_archive/950402eat_smart_garlic.html
Teresa G. Odle