Commonly known as garlic, is a species in the onion family Alliaceae. Its close relatives include the onion, shallot, and leek. Garlic has been used throughout recorded history for both culinary and medicinal purposes. It has a characteristic pungent, 'hot', flavor that mellows and sweetens considerably with cooking. [1] A 'head' of garlic, the most commonly used plant part, comprises numerous discrete 'cloves'. The leaves and stems are sometimes eaten, particularly while immature and tender.
Culinary uses
Garlic scapes are often harvested early so that the bulbs will grow bigger.
Garlic is widely used around the world for its pungent flavour, as a seasoning or condiment. Depending on the form of cooking, the flavor is either mellow or intense. It is often paired with onion, tomato, and/or ginger. The parchment-like skin is much like the skin of an onion, and is typically removed before using in raw or cooked form. An alternative is to coat heads of garlic and roast them in the oven. The garlic softens and can be extracted from individual cloves by squeezing one end.
Oils are often flavored with garlic cloves. Commercially prepared oils are widely available, but when preparing garlic-infused oil at home, there is a risk of botulism if the product is not stored properly. To reduce this risk, the oil should be refrigerated and used within one week. Manufacturers add chemicals and/or acids to eliminate the risk of botulism in their products.
In Chinese cuisine, the young bulbs are pickled for 3–6 weeks in a mixture of sugar, salt and spices. In Russia and the Caucasus, the shoots are pickled and eaten as an appetizer.
Medicinal use and health benefits
Garlic has been used as both food and medicine in many cultures for thousands of years, dating as far back as the time that the Egyptian pyramids were built. Garlic is claimed to help prevent heart disease, including atherosclerosis, high cholesterol, high blood pressure, and to improve the immune system. Garlic may also protect against cancer
However a rigorous, NIH-funded clinical trial published by the "Archives of Internal Medicine", on 26 February 2007, found that consumption of garlic, in any form, did not reduce cholesterol levels in patients with moderately high levels.
With regard to this clinical trial, Heart.org reports, "Despite decades of research suggesting that garlic can improve cholesterol profiles, a new NIH-funded trial found absolutely no effects of raw garlic or garlic supplements on LDL, HDL, or triglycerides." The website says, "The findings underscore the hazards of meta-analyses made up of small, flawed studies and the value of rigorously studying popular herbal remedies". [10] However, while garlic may not lower cholesterol levels in the bloodstream, this study does not contradict studies that show that garlic protects arteries from that cholesterol. For example, a Czech study found garlic supplementation reduced accumulation of cholesterol on vascular walls of animals. [11] Another study had similar results, with garlic supplementation significantly reducing the placque in the aorta's of cholesterol-fed rabbits. [12] Another study showed that supplementation with garlic extract inhibited vascular calcification in human patients with high blood cholesterol. [13] A study published in Preventive Medicine shows that garlic inhibits coronary artery calcification, a process that serves as a marker for plaque formation since the body lays down calcium in areas that have been damaged. In this year-long study, patients given aged garlic extract daily showed an average increase in their calcium score of 7.5%, while those in the placebo group had an average increase in calcium score of 22.2%.
One reason for garlic's beneficial effects may be its ability to lessen the amount of free radicals present in the bloodstream. According to a study published in Life Sciences, a daily dose of 1 ml/kg body weight of garlic extract for six months resulted in a significant reduction in oxidant (free radical) stress in the blood of patients with atherosclerosis. Since atherosclerotic plaques develop when cholesterol circulating in the bloodstream is damaged or oxidized, garlic's ability to prevent these oxidation reactions may explain some of its beneficial effects in atherosclerotic cardiovascular diseases. A German study published in Toxicology Letters indicates that garlic also greatly reduces plaque deposition and size by preventing the formation of the initial complex that develops into an atherosclerotic plaque. Called "nanoplaque," it is formed when calcium binds to proteoheparan sulfate and then to LDL cholesterol. Garlic prevents the binding of calcium to proteoheparan sulfate, thus decisively inhibiting plaque generation.
Research presented at the 6th Annual Conference on Arteriosclerosis, Thrombosis and Vascular Biology held by the American Heart Association in Washington, D.C., suggests that garlic can help prevent and potentially reverse atherosclerotic plaque formation. The laboratory studies, conducted by well-known German scientist Professor Güautnter Siegel, M.D., from the University of Medicine in Berlin, Germany, found that powdered garlic (Kwai ® garlic) reduced the formation of nanoplaque (the first building blocks of atherosclerotic plaque) by up to 40% and reduced the size of the nanoplaque that did form by up to 20%.
Laboratory research by US and Swedish scientists published in the August 2005 Proceedings of the National Academy of Sciences reveals the mechanism behind garlic's cardiovascular benefits. The compounds in garlic responsible for its pungency also excite a neuron pathway providing cardiovascular benefits. Garlic's pungency-and that of the other members of the Alliumgenus of plants, such as onions, leeks and chives-results from its organosulphur compounds, allicin and diallyl disulphide (DADS). In this current in vitro study, allicin and DADS were found to activate perivascular sensory nerve endings, inducing the relaxation and enlargement of blood vessels, lowering blood pressure and improving blood flow throughout the body.
Garlic's numerous beneficial cardiovascular effects are due to not only its sulfur compounds, but also to its vitamin C, vitamin B6, selenium and manganese:
Garlic is a very good source of vitamin C, the body's primary antioxidant defender in all aqueous (water-soluble) areas, such as the bloodstream, where it protects LDL cholesterol from oxidation. Since it is the oxidized form of LDL cholesterol that initiates damage to blood vessel walls, reducing levels of oxidizing free radicals in the bloodstream can have a profound effect on preventing cardiovascular disease.
Garlic's vitamin B6 helps prevent heart disease via another mechanism: lowering levels of homocysteine. An intermediate product of an important cellular biochemical process called the methylation cycle, homocysteine can directly damage blood vessel walls.
The selenium in garlic not only helps prevent heart disease, but also provides protection against cancer and heavy metal toxicity. A cofactor of glutathione peroxidase (one of the body's most important internally produced antioxidants), selenium also works with vitamin E in a number of vital antioxidant systems. Since vitamin E is one of the body's top defenders in all fat-soluble areas, while vitamin C protects the water-soluble areas, garlic, which contains both nutrients, does a good job of covering all the bases. Garlic is rich not only in selenium, but also in another trace mineral, manganese, which also functions as a cofactor in a number of other important antioxidant defense enzymes, for example, superoxide dismutase. Studies have found that in adults deficient in manganese, the level of HDL (the "good form" of cholesterol) is decreased.
In 2007 a BBC news story reported that Allium sativum may have beneficial properties, such as preventing and fighting the common cold. [14] This assertion has the backing of long tradition. Traditional British herbalism used garlic for hoarseness and coughs, both as a syrup and in a salve made of garlic and lard, which was rubbed on the chest and back. [15] The Cherokee also used it as an expectorant for coughs and croup.
Allium sativum has been found to reduce platelet aggregation and hyperlipidemia.
Garlic is also alleged to help regulate blood sugar levels. Regular and prolonged use of therapeutic amounts of aged garlic extracts lower blood homocysteine levels, and has shown to prevent some complications of diabetes mellitus. [19] [20] People taking insulin should not consume medicinal amounts of garlic without consulting a physician. In such applications, garlic must be fresh and uncooked, or the allicin will be lost.
Allium sativum may also possess cancer-fighting properties due to the presence of allylic sulfur compounds such as diallyl disulfide (DADs), believed to be an anticarcinogen. Decocted garlic extracts that are left to set overnight are very effective in healing wounds. In 1858, Louis Pasteur observed garlic's antibacterial activity, and it was used as an antiseptic to prevent gangrene during World War I and World War II. [22] More recently it has been found from a clinical trial that a mouthwash containing 2.5% fresh garlic shows good antimicrobial activity, although the majority of the participants reported an unpleasant taste and halitosis. In modern naturopathy, garlic is used as a treatment for intestinal worms and other intestinal parasites, both orally and as an anal suppository. Garlic cloves are used as a remedy for infections (especially chest problems), digestive disorders, and fungal infections such as thrush.
Garlic supplementation in rats along with a high protein diet has been shown to boost testosterone levels.
Dietary supplements in an "odourless" pill form, as are commonly available, claim to possess the medicinal benefits of garlic, without (in the words of one manufacturer) "the unsocial qualities associated with fresh garlic cloves".[citation needed] However independent validation (e.g. not sponsored by the pill manufacturers) through rigorously conducted clinical trials of the benefits, if any, of these pills is lacking or has been found to be negative, e.g. showing no beneficial effects.
Anti-inflammatory, anti-viral, anti-fungal, and anti-bacterial usage
Garlic, like onion, contains compounds that inhibit lipoxygenase and cyclooxygenase, (the enzymes that generate inflammatory prostaglandins and thromboxanes), thus markedly reducing inflammation. These anti-inflammatory compounds along with the vitamin C in garlic, especially fresh garlic, make it useful for helping to protect against severe attacks in some cases of asthma and may also help reduce the pain and inflammation of osteoarthritis and rheumatoid arthritis.
In addition, allicin, one of the sulfur-compounds responsible for garlic's characteristic odor, is a powerful anti-bacterial, anti-fungal and anti-viral agent that joins forces with vitamin C to help kill harmful microbes. In research studies, allicin has been shown to be effective not only against common infections like colds, flu, stomach viruses, and Candida yeast, but also against powerful pathogenic microbes including tuberculosis and botulism.
Although garlic alone appears unable to prevent infection with Helicobacter pylori (H. pylori), the bacterium responsible for most peptic ulcers, as well as gastritis, frequently eating this richly flavored bulb may keep H. pylori from doing much damage. A study recently conducted at Faith University in Istanbul, Turkey, compared two groups of healthy individuals: one was selected from individuals who regularly ate lots of raw and/or cooked garlic, while the other group was composed of individuals who avoided it. For 19 months, blood samples were regularly collected from both groups and evaluated for the presence of H.pylori. While the incidence of H.pylori was pretty comparable-the bacterium was found in 79% of garlic eaters and 81% of those who avoided garlic-the garlic-consuming group had a clear advantage in that antibodies to H.pylori were much lower in their blood compared to those who ate no garlic. (Antibodies are formed when the immune system reacts to anything it considers a potential pathogen, so less antibodies to H.pylori means less of the bacterium was present.) Among those who ate garlic, those who ate both raw and cooked garlic had even lower levels of antibodies than those who ate their garlic only raw or only cooked.[citation needed] Laboratory studies recently conducted at the University of Munich, Germany, help explain why garlic may be such a potent remedy against the common cold. In these studies, garlic was found to significantly reduce the activity of a chemical mediator of inflammation called nuclear transcription factor (NF) kappa-B.[citation needed]
NF kappa-B is itself activated as part of the immune system's inflammatory response to invading organisms and damaged tissue. So, anything that sets off an inflammatory response (e.g. allergenic foods, a cold or other infection, physical trauma, excessive exercise, excessive consumption of foods containing high levels of omega-6 fatty acids-such as meat, corn or safflower oil) can trigger a surge in NF kappa-B, which in turn not only promotes inflammation but sets up ideal conditions for viruses, including HIV, to replicate. In the blood samples tested in these German studies, unfertilized garlic caused a 25% drop in NF kappa-B activity, while sulfur-fertilized garlic lowered NF kappa-B activity by a very robust 41%.
Results of two studies suggest that garlic is a potent antibiotic, even against strains that have become resistant to many drugs. One study conducted at the University of California Irvine Medical Center and published in the December 2003 issue of Nutrition showed that garlic juice, even when diluted up to 1:128 of the original juice, demonstrates significant antibacterial activity against a spectrum of pathogens including antibiotic-resistant strains such as methicillin- and ciprofloxacin-resistant staphylococci, vancomycin-resistant enterococci, and ciprofloxacin-resistant Pseudomonas aeruginosa. A second study found that garlic was able to inhibit methicillin-resistant Staphylococcus aureus (MSRA) from human patients that was injected into laboratory animals.(MSRA is one of the antibiotic resistant bacteria whose incidence has risen dramatically in recent years in hospitals.)
Anti-carcinogenic usage
Cooking garlic with meat appears to reduce the production of carcinogenic (cancer-causing) chemicals that can occur in meat as a result of cooking methods, such as grilling, that expose meat to high temperatures. Research presented at the American Association for Cancer Research's Frontiers in Cancer Prevention Research meeting in Baltimore, MD, suggests that the phytonutrient responsible for garlic's pungency may help prevent cancer by inhibiting the effects of one such carcinogen called PhIP.[citation needed]
A cancer-causing heterocyclic amine, PhIP is thought to be one reason for the increased incidence of breast cancer among women who eat large quantities of meat because it is rapidly transformed into DNA-damaging compounds.[citation needed]
Diallyl disulphide (DAS), an organosulfur compound that gives garlic its unique flavor, has been shown to inhibit the transformation of PhIP into carcinogens. DAS blocks this transformation by decreasing the production of the liver enzymes (the Phase I enzymes CYP1A1, CYP1A2 and CYP1B1) that transform PhIP into activated DNA-damaging compounds.[citation needed]
In addition, DAS signals the genes responsible for producing two protective antioxidant enzymes, (glutathione-S-transferase (GST) and superoxide dismutase (SOD), which help protect the body against harmful compounds such as those produced from PhIP. These findings suggest that making garlic, onion, chives and other Allium vegetables, all of which contain DAS, a staple part of your healthiest way of eating may help in preventing breast cancer induced by PhIP in well-done meats. And enjoying these DAS-rich foods may help protect the men you love as well. Consumption of Allium vegetables has also been associated with a reduced risk of prostate cancer.
Properties
When crushed, Allium sativum yields allicin, a powerful antibiotic and anti-fungal compound (phytoncide). It also contains alliin, ajoene, enzymes, vitamin B, minerals, and flavonoids.
The phytochemicals responsible for the sharp flavor of garlic are produced when the plant's cells are damaged. When a cell is broken by chopping, chewing, or crushing, enzymes stored in cell vacuoles trigger the breakdown of several sulfur-containing compounds stored in the cell fluids. The resultant compounds are responsible for the sharp or hot taste and strong smell of garlic. Some of the compounds are unstable and continue to evolve over time. Among the members of the onion family, garlic has by far the highest concentrations of initial reaction products, making garlic much more potent than onions, shallots, or leeks. [25] Although people have come to enjoy the taste of garlic, these compounds are believed to have evolved as a defensive mechanism, deterring animals like birds, insects, and worms from eating the plant.
A large number of sulfur compounds contribute to the smell and taste of garlic. Diallyl disulfide is believed to be an important odour component. Allicin has been found to be the compound most responsible for the spiciness of raw garlic. This chemical opens thermoTRP (transient receptor potential) channels that are responsible for the burning sense of heat in foods. The process of cooking garlic removes allicin, thus mellowing its spiciness. [27]
When eaten in quantity, garlic may be strongly evident in the diner's sweat and breath the following day. This is because garlic's strong smelling sulfur compounds are metabolized forming allyl methyl sulfide. Allyl methyl sulfide (AMS) cannot be digested and is passed into the blood. It is carried to the lungs and the skin where it is excreted. Since digestion takes several hours, and release of AMS several hours more, the effect of eating garlic may be present for a long time.
This well-known phenomenon of "garlic breath" is alleged to be alleviated by eating fresh parsley. The herb is, therefore, included in many garlic recipes, such as Pistou and Persillade. However, since the odour results mainly from digestive processes placing compounds such as AMS in the blood, and AMS is then released through the lungs over the course of many hours, eating parsley provides only a temporary masking. One way of accelerating the release of AMS from the body is the use of a sauna. Due to its strong odor, garlic is sometimes called the "stinking rose".
Because garlic passes into the bloodstream, it can be a useful mosquito repellent. This is most likely the cause of the myth that vampires hate garlic.
[edit] Superstition and mythology
Garlic has been regarded as a force for both good and evil. A Christian myth considers that after Satan left the Garden of Eden, garlic arose in his left footprint, and onion in the right. [28] In Europe, many cultures have used garlic for protection or white magic, perhaps owing to its reputation as a potent preventative medicine. [29] Central European folk beliefs considered garlic a powerful ward against demons, werewolves, and vampires. [29] To ward off vampires, garlic could be worn, hung in windows or rubbed on chimneys and keyholes. [30]
The association of garlic to evil spirits may be based on the antibacterial, antiparasitic value of garlic, which could prevent infections that lead to delusions, and other related mental illness symptoms.
Cautions
Known adverse effects of garlic include halitosis (non-bacterial), indigestion, nausea, emesis and diarrhea.
Garlic should not be taken with warfarin, antiplatelets, saquinavir, antihypertensives, or hypoglycemic drugs.
Cases of botulism have been caused by consuming garlic-in-oil preparations. It is important to add acid when creating these mixtures and to keep them refrigerated to retard bacterial growth.
Whilst culinary quantities are considered safe during pregnancy and breastfeeding, extremely large quantities of garlic and garlic supplements have been linked with a raised risk of bleeding. Garlic may cause abortion. Some breastfeeding mothers have found their babies slow to feed and have noted a garlic odour coming from their baby when they have consumed garlic.
The side effects of long-term garlic supplementation, if any exist, are largely unknown and no FDA-approved study has been performed. However, garlic has been consumed for several thousand years without any adverse long-term effects, suggesting that modest quantities of garlic pose, at worst, minimal risks to normal individuals.
There have been several reports of serious burns resulting from garlic being applied topically for various purposes, including naturopathic uses and acne treatment. [36] On the basis of numerous reports of such burns, including burns to children, topical use of raw garlic, as well as insertion of raw garlic into body cavities is strongly discouraged and could lead to serious injury. In particular, topical application of raw garlic to young children is extremely risky.
Source: http://en.wikipilipinas.org/index.php?title=Allium_sativum
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