The healthful properties of garlic are legion and have been identified and validated by hard empirical science in over a thousand scientific reports this last decade. Areas of beneficial activity include anti-AIDS, anti-cancer and anti-cardiovascular disease and anti-infectious properties, amongst others. Garlic is furthermore uniquely the richest dietary source of many otherwise rare healthful sulphur compounds, plus organic selenium as well as being one of the best sources of organic germanium (after ginseng & green tea, which latter is the richest food source known) besides an impressive array of other essential nutrients and active health-promoting phytochemicals.
Various forms of garlic are available, the most effective being fresh, powdered, distilled and especially aged garlic, which latter lacks the irritant effect of fresh garlic, yet possesses equal or greater bio-active range and potency.
Pharmacologic activities of aged garlic extract in comparison with other garlic preparations
We investigated the pharmacologic activities of four garlic preparations, raw garlic juice (RGJ), heated garlic juice (HGJ), dehydrated garlic powder (DGP) and aged garlic extract (AGE). The study used three animal models, i.e., testicular hypogonadism (hypospermatogensis and impotence) induced by warm water treatment, intoxication of acetaldehyde and growth of inoculated tumor cells. RGJ was found to be effective only in recovery of testicular function. The efficacy of HGJ was observed in three models; however, it did not improve impotence. DGP was effective in recovery of spermatogenesis and stimulated acetaldehyde detoxification. Significant beneficial effects of AGE were found in all three models. Although all four garlic preparations significantly enhanced natural killer (NK) and killer cell activities of the spleen cells of tumor-bearing mice, only AGE and HGJ inhibited the growth of inoculated tumor cells. These results suggest that different types of garlic preparations have different pharmacologic properties, and among the four garlic preparations studied, AGE could be the most useful garlic preparation. (Kasuga S, et al, J Nutr, 131(3): 1080S, 2001)
Antioxidant health effects of aged garlic extract
Oxidative modification of DNA, proteins and lipids by reactive oxygen species (ROS) plays a role in aging and disease, including cardiovascular, neurodegenerative and inflammatory diseases and cancer. Extracts of fresh garlic that are aged over a prolonged period to produce aged garlic extract (AGE) contain antioxidant phytochemicals that prevent oxidant damage. These include unique water-soluble organosulfur compounds, lipid-soluble organosulfur components and flavonoids, notably allixin and selenium. Long-term extraction of garlic (up to 20 mo) ages the extract, creating antioxidant properties by modifying unstable molecules with antioxidant activity, such as allicin, and increasing stable and highly bioavailable water-soluble organosulfur compounds, such as S:-allylcysteine and S:-allylmercaptocysteine. AGE exerts antioxidant action by scavenging ROS, enhancing the cellular antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, and increasing glutathione in the cells. AGE inhibits lipid peroxidation, reducing ischemic/reperfusion damage and inhibiting oxidative modification of LDL, thus protecting endothelial cells from the injury by the oxidized molecules, which contributes to atherosclerosis. AGE inhibits the activation of the oxidant-induced transcription factor, nuclear factor (NF)-kappaB, which has clinical significance in human immunodeficiency virus gene expression and atherogenesis. AGE protects DNA against free radical-mediated damage and mutations, inhibits multistep carcinogenesis and defends against ionizing radiation and UV-induced damage, including protection against some forms of UV-induced immunosuppression. AGE may have a role in protecting against loss of brain function in aging and possess other antiaging effects, as suggested by its ability to increase cognitive functions, memory and longevity in a senescence-accelerated mouse model. AGE has been shown to protect against the cardiotoxic effects of doxorubicin, an antineoplastic agent used in cancer therapy and against liver toxicity caused by carbon tetrachloride (an industrial chemical) and acetaminophen, an analgesic. Substantial experimental evidence shows the ability of AGE to protect against oxidant-induced disease, acute damage from aging, radiation and chemical exposure, and long-term toxic damage. Although additional observations are warranted in humans, compelling evidence supports the beneficial health effects attributed to AGE, i.e., reducing the risk of cardiovascular disease, stroke, cancer and aging, including the oxidant-mediated brain cell damage that is implicated in Alzheimer's disease. (Borec C, J Nutr, 131(3): 1010S, 2001)
Local natural health diet guru Mary-Anne Shearer, in a newsletter recently linked Candida over-growth to the use of antibiotics, even natural ones like garlic, causing confusion amongst readers and enthusiasts along the grapevine. Sure, synthetic antibiotics, and even natural antibiotics like garlic (and colloidal silver) can cause or contribute to the problem, but not necessarily so, unless colon ecology is seriously deranged prior to or because of inappropriate use of these substances. With correct usage, in the case of higher doses, involving a “viable” probiotic at the appropriate time after an intensive antimicrobial intervention and a cessation thereof, at least temporarily with garlic (or colloidal silver) whilst the beneficial organisms are established in a non-competitive milieu, colon ecology can be effectively corrected and maintained, in spite of, if not because of, the (correct) use of these useful substances.
Urethritis, vaginitis and oral thrush are caused by a yeast-like fungus of the candida group. Because of solid scientific research, garlic is the number one natural treatment for candida infections, used by thousands of holistic physicians in America (Stephen Fulder, PhD, Garlic: Nature’s Original Remedy, Healing Arts Press, 1991) and is often recommended as a nutritional supplement and as a primary food by natural health professionals in rational dietary programmes for candidiasis (Benjamin Lau, MD, PhD, Garlic for Health, Lotus Light Publications, 1988); sample online references: (Stephen A. Levine, PhD, & Larry Jordan, Candida albicans, The Nutrition Notebook[ http://www.springboard4health.com/notebook/health_candida_albicans.html]); (Elson M. Haas MD, Nutritional Program for Yeast Syndrome, Health World OL [ http://www.healthy.net/library/books/haas/medtreat/yeastsyn.htm]).
Following earlier garlic antibiotic experiments, researchers expressed the opinion that garlic extracts possessed the potent ability to kill dangerous organisms in the range of 1:85,000 – 1:125,000 (Cavallito C, et al, J Am Chem Soc, 69:1710, 1947), without destroying those vitally necessary to bodily health (Klosa J, German Medical Monthly, Mar 1950). Whilst it is not quite true to say that garlic selects only the unfriendly organisms for attack, it does tend to attack foe rather than friend, but nevertheless knocks out some of each. However, the beneficial bacteria that live naturally in the gut soon recover, whilst the invaders do not. At lower doses, garlic does not kill invaders but simply stops their multiplication, affording the body an opportunity to marshal its own defences. Garlic is the only antibiotic, which at the same time as fighting microbial invaders, also protects the body against poisons produced by infection. (Stephen Fulder, PhD, Garlic: Nature’s Original Remedy, Healing Arts Press, 1991)
Garlic is a unique antibiotic because it also nourishes beneficial bacteria, since oligosaccharides found in foods such as garlic and onions are prebiotics which selectively stimulate the growth activities of both good lactobacilli, Acidophilus and Bifidobacteria, in the colon, thereby improving health (Gibson G, et al, Aspects of Health and Disease Involving the Human Colonic Microbiotica, Summary Report of a First Plenary Meeting on Functional Food Science in Europe, Intl Life Sci Inst, 2-4 Apr, 1996); (Macfarlane G, Cummings J, BMJ, 318(999), 1999); (Roberfroid M, Am J Clin Nutr, 71(6), 2000). Fungal growth is inhibited by low concentrations of garlic and lactic acid bacteria are the least sensitive microorganisms to the inhibitory effects of garlic, requiring higher concentrations (Rees L, et al, World J Microbiol Biotechnol, 9: 303, 1993).
The Herxheimer effect is pronounced in the use of garlic but the duration appears to be less than with antibiotics (Novus Research Report No A-66013, Novus Research Archive, August, 1995). The maximum tolerable dose of a fresh extract of garlic administered orally to human volunteers was determined to be 25 ml of garlic extract. Larger amounts caused severe burning sensations in the esophagus and the stomach and vomiting. After oral ingestion of 25 ml of the extract, anticandidal and anticryptococcal activities were detected in undiluted serum 0.5 and 1 h after ingestion. After high doses, even the blood can kill the infecting fungi. (Caporaso N, et al, Antimicrob Agents Chemother, 23(5), 1983) Current therapeutic dose recommendations are 4 gms of fresh garlic or 1-2 cloves per day (Murray J, Literature Review, Univ Med Dent New Jersey, 1999).
Of 50 medicinal plants belonging to 26 families studied for their antimicrobial activity, only nine showed antifungal activity. Garlic exhibited activity against both filamentous and non-filamentous fungi. (Srinivasan D et al, J Ethnopharmacol, 74 (3), 2001) Garlic has a variety of antimicrobial activities: antibacterial; antifungal (particularly against Candida albicans); antiparasitic (including protozoa); and antiviral. Beneficial effects against Candida and candidiasis have been demonstrated in several diverse scientific studies: (KabelÃk J, Pharmazie, 25(4), 1970); (Tynecka Z, Gos Z, Acta Microbiol Pol B, 5(1), 1973); (Tynecka Z, Gos Z, Ann Univ Mariae Curie Sklodowska [Med], 30(5), 1975); (Barone F, Tansey M, Mycologia, 69(4), 1977); (Collins E, Hardt P, J Dairy Sci, 63:830, 1980); (Prasad G, Sharma V, Br Vet J, 136:448, 1980); (Sandhu D, et al, Mykosen, 23(12), 1980); (Adetumbi M, Med Hypotheses 12(3), 1983); (Yoshida S, et al, Appl Environ Microbiol, 53:615, 1987); (Ghannoum M, J Appl Bacteriol 68(2), 1990); (Gerhardt R, Arzneim Forsch/Drug Res, 41:800, 1991); (Ankri S, Mirelman D, Microbes Infect, 1(2), 1999); (Sasaki J, et al, J Nutr Sci Vitaminol, 45(6), 1999); (Perfect J, Cox G, Drug Resist Updates, 2(4), 1999); (Vaijayayanthimala J, et al, Phytother Res, 14(3), 2000); (Tsao S, Yin M, J Med Microbiol 50(7), 2001).
Allicin, a compound found in garlic and responsible for much of the therapeutic properties of garlic has never been found in the blood of people who have consumed garlic, indicating that it is rapidly converted to other compounds (Reuter H, Phytother, 12: 83, 1991). Allicin is the product of an enzymatic reaction. When fresh garlic is crushed, allinase acts upon the compound alliins to produce allicin. This natural compound loses much of its beneficial properties within hours because it begins to react with garlic's other compounds as soon as the clove is crushed. However, the end product is ajoene, which possesses antifungal qualities (Yamada Y, Azuma K, Antimicrob Agents Chemother, 1977 11(4), 1977). The antifungal activity of six fractions derived from garlic was investigated in an in vitro system. Ajoene had the strongest activity. The growth of Candida albicans was inhibited by ajoene at less than 20 micrograms/ml. (Yoshida S, et, Appl Environ Microbiol, 53 (3), 1987)
The mode of anticandidal action of garlic was studied in Candida albicans. Protein and nucleic acid syntheses were inhibited to the same extent as growth, but lipid synthesis was completely arrested. Blockage of lipid synthesis is likely an important component of the anticandidal activity of garlic. (Adetumbi M, et al, Antimicrob Agents Chemother, 30(3), 1986)Garlic treatment affected the structure and integrity of the outer surface of the yeast cells. Growth of C. albicans in the presence of garlic suggests that it exerts its effect by oxidation, causing inactivation of enzymes and subsequent microbial growth inhibition (Ghannoum M, J Gen Microbiol, 134(Pt 11), 1988). Researchers have confirmed that the phagocytic enhancing activity of garlic can be attributed the control of Candida albicans in a living model to this effect(Tadi P, et al, Intl Clin Nutr Rev, 10(4), 1990). Garlic strongly enhances phagocytosis of peritoneal macrophages (the ability of immune cells to engulf foreign agents) and increases natural killer cell activity both in vitro and in vivo (Kyo E, et al, Phytomed, 4(4), 1997).
Although Candida organisms are primarily inhabitants of the lower alimentary canal, it is often also genital and even cutaneous. Candidiasis may actually presage progression to AIDS, where Candida overgrowth can be a major opportunistic complication, causing invasive oral infections, even in the esophagus, upper respiratory tract, and lungs. In addition to controlling this, garlic has furthermore been found to enhance natural killer cell activity and to improve helper/suppressor T-cell ratios in AIDS patients after only six weeks intake to within the normal range for all subjects. Patients in these studies noted significant improvements in their candidiasis (Abdullah T, et al, J Nat Med Assoc, 80(4), 1988); (Abdullah T, et al, Deutsche Zeitschrift Fur Onkologie, 21:52, 1989). Garlic has especially potent antifungal activity toward growing Candida albicans cells, clearly superior to all established appropriate antibiotics tested (Moore G, Atkins R, Mycologia, 69:341, 1977) (most of which are still in use today in some form or another) and with microbicidal concentrations 10-100 times higher than inhibitory concentrations (Naganawa R, et al, Appl Environ Microbiol, 62:11, 1996), the control potential far exceeds any negative potential.
Closer to home, Prof. Sid Cywes, at the University of Cape Town and Peter de Wet, chief paediatric surgery research technologist at the Red Cross Children’s Hospital tried garlic out on the culture medium for burn infections and other organisms and were astonished that it could also combat serious candida yeast infection (MRC News, Med Res Council SA, 31(5), 2000). Since then, about thirty very sick infants, where broad-spectrum antibiotics failed to bring improvement, have been given fresh allicin enterally. The allicin treatment brought about a significant success. One of the active ingredients in garlic is a compound called allicin. On crushing fresh garlic, an enzyme called alliinase is released which rapidly converts the odorless compound alliin into allicin bearing the typical odor of garlic. Allicin is highly unstable and rapidly converts to other sulfur-compounds such as ajoene. It is however allicin and ajoene which have been the main subject of research. These compounds block the enzymes that are necessary for metabolism of the micro-organisms. They have also been shown to inhibit the growth of more than 23 organisms and a very interesting point is that no resistance has been found up to date. (Limson J, Feature: The science behind the legendary healing properties of garlic. Science in Africa (Online), Sat 24 Nov, 21:17:10, 2001)
The safe, diverse microbicidal potential of garlic obviously still delights researchers, in spite of its non-patentability:(Nielsen P, Rios R, Int J Food Microbiol, 60(2-3), 2000); (Avato P, et al, Phytomed, 7(3), 2000); (O’Gara E, et al, Appl Environ Microbiol, 66(5), 2000); (Ledezma E, J Am Acad Dermatol, 43(5 Pt 1), 2000); (Elsom K, et al, Microbial Ecology Health Dis, 12(2), 2000); (Tirranen L, Acta Astronaut, 49(2), 2001); (Ross Z, et al, Appl Environ Microbiol, 67(1), 2001); (Unal R, et al, J Food Prot, 64(2), 2001); (Singh B, et al, Food Microbiol, 18(2), 2001); (Luo R, et al, Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi, 15(2), 2001); (Galvano F, J Food Prot, 64(1), 2001); (Harris J, et al, Appl Microbiol Biotechnol 57:282, 2001); (Matsuura H, J Nutr, 131(3s), 2001); (Staba E, et al, J Nutr, 131(3s), 2001); (Singh U, et al, Indian J Exp Biol, 39(4), 2001); (Josling P, Adv Ther, 18(4), 2001). In conclusion, given the wide antimicrobial range of garlic, not to mention its other health benefits, plus the fact that today we find ourselves far from the optimum health once enjoyed in the Garden of Eden, surely on the basis of the preponderance of evidence, we would be foolish not to use garlic in our diet, based on mere advice to the contrary.
And God said, “See, I have given you every herb that yields seed which is on the face of all the earth, and every tree whose fruit yields seed; to you it shall be for food”. Genesis 1:29. The Holy Bible, New King James Version.
Allyl sulfur compounds are the major active constituents found in crushed garlic. Research has revealed that garlic and its lipid- or water-soluble components have many pharmacologic properties; however, studies also demonstrate that heating has a negative influence on these beneficial effects. Our studies showed that as little as 60 s of microwave heating or 45 min of oven heating can block garlic's ability to inhibit in vivo binding of mammary carcinogen DMBA metabolites. Allowing crushed garlic to "stand" for 10 min before microwave heating for 60 s prevented the total loss of anticarcinogenic activity, which relates to its anticancer properties. (Song K & Milner J, J Nutr, 131(3): 1054S, 2001)
Garlic exhibits a broad antibiotic spectrum against both gram-positive and gram-negative bacteria. Noteworthy results published include the following: 1) raw juice of garlic was found to be effective against many common pathogenic bacteria-intestinal bacteria, which are responsible for diarrhea in humans and animals; 2) garlic is effective even against those strains that have become resistant to antibiotics; 3) the combination of garlic with antibiotics leads to partial or total synergism; 4) complete lack of resistance has been observed repeatedly; 5) even toxin production by microorganisms is prevented by garlic. Helicobacter pylori (H. pylori) is a bacterium implicated in the etiology of stomach cancer and ulcers. The incidence of stomach cancer is lower in populations with a high intake of allium vegetables. We have demonstrated in vitro that H. pylori is susceptible to garlic extract at a fairly moderate concentration. Even some antibiotic-resistant H. pylori strains are susceptible to garlic. (Sivam G, J Nutr, 131(3): 1106S, 2001)
The antimicrobial effects of aqueous garlic extracts are well established but those of garlic oil (GO) are little known. GO sulfide constituents, and garlic powder (GP) were compared in tests against human enteric bacteria. All bacteria tested, which included both gram-negative and -positive bacteria and pathogenic forms, were susceptible to garlic materials. Based upon its thiosulfinate content, GP was more active than GO against most bacteria, although some properties of GO are identified as offering greater therapeutic potential. (Ross Z, Appl Environ Microbiol, 67(1): 475, 2001)
The effects of garlic preparations, including dehydrated raw garlic powder (RGP), dehydrated boiled garlic powder (BGP) and aged garlic extract (AGE), on the gastric mucosa were determined. Among the three preparations, RGP caused severe damage, including erosion. BGP also caused reddening of the mucosa, whereas AGE did not cause any undesirable effects. These results suggest that caution be used with regard to safety and effectiveness when choosing a garlic preparation because some preparations may have undesirable effects, including gastrointestinal problems. (Hoshino T, J Nutr, 131(3): 1109S, 2001)
Epidemiological and laboratory studies provide insight into the anticarcinogenic potential of garlic and its constituent compounds. Part of the protection from these compounds probably relates to a block in nitrosamine formation and metabolism. However, blockage in the initiation and promotion phases of the carcinogenicity of various compounds, including polycyclic hydrocarbons, provide evidence that garlic and its constituents can alter several phase I and II enzymes. Their ability to block tumors in a variety of sites including skin, mammary and colon, suggests a general mechanism of action. Changes in DNA repair and in immunocompetence may also account for some of this protection. Some, but not all, allyl sulfur compounds can also effectively retard tumor proliferation and induce apoptosis. Changes in cellular thiol and phosphorylation stains may account for some of these antitumorigenic properties. The anticarcinogenic potential of garlic can be influenced by several dietary components including specific fatty acids, selenium, and vitamin A. Garlic and its constituents can suppress carcinogen formation, carcinogen bioactivation, and tumor proliferation. (Milner J, J Nutr, 131(3): 1027S, 2001)
In the past decade, the cancer-protective effects of garlic have been well established by epidemiologic studies and animal experiments. However, the cardiovascular-protective properties of garlic are less well understood, in particular, the reported hypocholesterolemic effect. In a recent randomized, double-blind, placebo-controlled intervention study, we showed that aged garlic extract (AGE) supplementation was effective in lowering plasma concentration of total cholesterol by 7% and LDL cholesterol by 10% in hypercholesterolemic men compared with subjects consuming a placebo.(Yeh Y, J Nutr, 131(3): 989S, 2001)
Aged garlic protects the small intestine from antitumour drug-induced damage. (Horie T, et al, J Nutr 131(3s): 1071, 2001)
Most chemical and biological studies about garlic have been conducted using organosulfur compounds. However, a variety of steroid saponins from garlic are being increasingly recognized for their importance in biological processes. This report demonstrates in vitro antifungal antitumor cytotoxicity and blood coagulability as well as cholesterol-lowering effects effects of steroid saponins from garlic and aged garlic extract. (Matsuura H, J Nutr, 131(3): 1000S, 2001)
Animal and in vitro studies provide evidence of an anticarcinogenic effect of active ingredients in garlic. This study reviewed the epidemiologic literature on garlic consumption Site-specific case-control studies of stomach and colorectal cancer, in which multiple reports were available, suggest a protective effect of high intake of raw and/or cooked garlic. Evidence from available studies suggests a preventive effect of garlic consumption in stomach and colorectal cancers.(Fleischauer A, J Nutr, 131(3): 1032S, 2001)
There is increasing evidence that allium derivatives from garlic have significant antiproliferative actions on human cancers. Both hormone-responsive and hormone-unresponsive cells lines respond to these derivatives. The effects shown by allium derivatives include induction of apoptosis, regulation of cell cycle progression and modification of pathways of signal transduction. Allium derivatives appear to regulate nuclear factors involved in immune function and inflammation, as well as in cellular proliferation. Our own studies indicate that allium derivatives inhibit proliferation of the human prostate cancer cell line and the human breast cancer cell line. (Pinto J & Rivlin R, J Nutr, 131(3): 1058S, 2001)
Oxidative modification of LDL has been recognized as playing an important role in the initiation and progression of atherosclerosis. In this study, we determined that aged garlic extract (AGE) may be useful for prevention of atherosclerosis. (Ide N & Lau B, J Nutr, 131(3): 1020S, 2001)
Garlic is known for its pharmacologic and nutritional properties. In previous studies, garlic elicited a reduction in plasma levels of lipids by inhibiting hepatic cholesterol synthesis. The aim of this study was to investigate in an in vivo model the effects of garlic extract and some fractions on cholesterol levels and vascular reactivity in cholesterol-fed rats. Plasma concentration of cholesterol was 58 mg/dL (100%) at the beginning of the study and increased to 102 mg/dL (153%; hypercholesterolemic group) at the end of the treatment. Plasma total cholesterol decreased in all groups treated with garlic; moreover, this effect was higher in rats fed raw garlic fractions and extracts. LDL decreased significantly with respect to the hypercholesterolemic group in all groups treated with garlic fractions and extracts (P: < 0.01). These data suggest that garlic fractions could prevent diet-induced hypercholesterolemia and vascular alterations in the endothelium-dependent relaxation associated with atherosclerosis. (Slowing K, et al, J Nutr, 131(3): 994S, 2001)
Using various kinds of models, we examined the effects of aged garlic extract (AGE) on immune functions. These studies strongly suggest that AGE could be a promising candidate as an immune modifier, which maintains the homeostasis of immune functions. These studies strongly suggest that AGE could be a promising candidate as an immune modifier, which maintains the homeostasis of immune functions. (Kyo E, et al, J Nutr, 131(3): 1075S, 2001)
The health benefits of garlic likely arise from a wide variety of components, possibly working synergistically. The complex chemistry of garlic makes it plausible that variations in processing can yield quite different preparations. Highly unstable thiosulfinates, such as allicin, disappear during processing and are quickly transformed into a variety of organosulfur components. The efficacy and safety of these preparations in preparing dietary supplements based on garlic are also contingent on the processing methods employed. Although there are many garlic supplements commercially available, they fall into one of four categories, i.e., dehydrated garlic powder, garlic oil, garlic oil macerate and aged garlic extract (AGE). Garlic and garlic supplements are consumed in many cultures for their hypolipidemic, antiplatelet and procirculatory effects. In addition to these proclaimed beneficial effects, some garlic preparations also appear to possess hepatoprotective, immune-enhancing, anticancer and chemopreventive activities. (Amagase H, et al, J Nutr, 131(3): 955S, 2001)
It has been known for several decades that hypercholesterolemia is a major risk factor for atherosclerosis and that lowering of cholesterol can significantly reduce risk for cardiovascular diseases. More recently, oxidation of LDL has been recognized as playing an important role in the initiation and progression of atherosclerosis. Short-term supplementation of garlic in human subjects has demonstrated an increased resistance of LDL to oxidation. These data suggest that suppressed LDL oxidation may be one of the powerful mechanisms accounting for the antiatherosclerotic properties of garlic. (Lau B, J Nutr, 131(3): 985S, 2001)
Of the many beneficial actions of garlic, inhibition of the growth of cancer is perhaps the most remarkable. Our previous animal studies demonstrated that aged garlic extract was highly effective, and unlike the approved immunotherapy for human bladder cancer, bacillus Calmette-Guerin (BCG), garlic was effective when added to the diet. Garlic can detoxify carcinogens by stimulation of cytochrome P(450) enzymes, antioxidant activity or sulfur compound binding. Studies demonstrate a direct toxic effect of garlic to sarcoma and gastric, colon, bladder and prostate cancer cells in tissue culture. The most likely explanation of this effect is immune stimulation. Comparison of the effects of garlic to BCG immunotherapy reveals many similarities. Both stimulate proliferation of lymphocytes and macrophage phagocytosis, induce the infiltration of macrophages and lymphocytes in transplanted tumors, induce splenic hypertrophy, stimulate release of interleukin-2, tumor necrosis factor-alpha and interferon-gamma, enhance natural killer cell, killer cell and lymphokine-activated killer cell activity. These activities represent effective stimulation of the immune response. Studies suggest that garlic may be useful in preventing the suppression of immune response that is associated with increased risk of malignancy. Data suggest that maintenance of immune stimulation can significantly reduce the risk of cancer. (Lamm D & Riggs D, J Nutr, 131(3): 1067S, 2001)
Aged garlic extract (AGE) has been shown previously to have moderate cholesterol-lowering and blood pressure-reducing effects. We investigated whether platelet function, a potential risk factor for cardiovascular disease, can be inhibited by AGE administration. AGE exerts selective inhibition on platelet aggregation and adhesion, platelet functions that may be important for the development of cardiovascular events such as myocardial infarction and ischemic stroke. (Steiner M, J Nutr, 131(3): 980S, 2001)
Garlic detoxifies chemical carcinogens and prevent carcinogenesis and can also directly inhibit the growth of cancer cells. Garlic stimulates immunity, including macrophage activity, natural killer and killer cells, and LAK cells, and to increase the production of IL-2, TNF, and interferon-gamma. These cytokines are associated with the beneficial Th1 antitumor response, which is characteristic of effective cancer immunotherapies. Garlic stimulates the proliferation of macrophages and lymphocytes and protects against the suppression of immunity by chemotherapy and ultraviolet radiation. Garlic is not a panacea for cancer, but its broad range of beneficial effects are worthy of serious consideration for the prevention and treatment of cancer. (Lamm D & Riggs D, Urol Clin North Am, 27(1): 157, 2000)
Nephrotic syndrome (NS) is characterized by proteinuria, oxidative stress and endogenous hyperlipidemia. Hyperlipidemia and oxidative stress may be involved in coronary heart disease and the progression of renal damage in these patients. Garlic has been suggested to be beneficial in various disease states. Some of the beneficial effects of garlic may be secondary to its hypolipidemic and antioxidant properties. Garlic treatment diminished significantly total-cholesterol, LDL-cholesterol and triglycerides, but not HDL-cholesterol in chronic NS. These data indicate that garlic treatment ameliorates hyperlipidemia and renal damage in chronic NS, which is unrelated to proteinuria or antioxidant enzymes.(Pedraza-Chaverri J, Mol Cell Biochem, 211(1-2): 69, 2000)
The immunomodulatory effects of naturally occurring sulphur compounds in garlic include the total white blood cell (WBC) count being enhanced significantly and bone-marrow cellularity also being increased significantly in treated animals, suggesting an immunostimulating effect for garlic sulphur compounds. (Kuttan G, J Ethnopharmacol, 72(1-2), 2000)
When the rats were fed with a high cholesterol diet mixed with garlic powder, there was a significant reduction in their serum cholesterol levels compared with the group, which were on a diet containing high cholesterol without garlic powder. The blood pressure of the animals receiving garlic powder and high cholesterol diet was significantly lower as compared to the high cholesterol and control diet group. These results show that garlic is beneficial in reducing blood cholesterol, triglycerides levels and systolic blood pressure in hypercholesterolemic rats. Our experimental results show that garlic may beneficially affect two risk factors for atherosclerosis--hyperlipidemia and hypertension. (Ali M, et al, Prostaglandins Leukot Essent Fatty Acids, 62(4): 253, 2000)
To find a better contact solvent to dissolve gallstones we studied in vitro use of garlic oil and compared it with monooctanoin. Garlic oil dissolved the cholesterol gallstones in proportion to the concentration used. The gall stone fragmentation was faster [6 hours V/s 36 hours] and more [88.30% V/s 71.01%] by garlic oil in comparison to monooctanoin in test tubes and even in artificial gallbladder and common bile duct models. Garlic oil is a better contact dissolving agent of gallstones than monooctanoin. (Nijhawan S, et al, Trop Gastroenterol, 21(4): 177, 2000)
Chronic Helicobacter pylori disease is reduced with Allium vegetable intake. This study was designed to assess the in vivo anti-H. pylori potential of a variety of garlic substances. The MICs (range, 8 to 32 microg/ml) and minimum bactericidal concentrations (MBCs) (range, 16 to 32 microg/ml) of undiluted garlic oil (GO) were smaller than those of garlic powder (GP) (MIC range, 250 to 500 microg/ml; MBC range, 250 to 500 microg/ml) but greater than the MIC of allicin (4. 0 microg/ml) present in GP. Substantial in vitro anti-H. pylori effects of pure GO and GP and their diallyl sulfur components exist, suggesting their potential for in vivo clinical use against H. pylori infections. (O’Gara E, et al, Appl Environ Microbiol, 66(5): 2269, 2000)
Reactive oxygen species are involved in gentamicin (GM) nephrotoxicity, and garlic is effective in preventing or ameliorating oxidative stress. The protective effect of garlic is associated with the prevention of the decrease of Mn-SOD and GPx activities and with the rise of lipoperoxidation in renal cortex. (Pedraza-Chaverri J, et al, Free Radic Biol Med, 1;29(7): 602, 2000)
Garlic has been widely reported to protect against cardiovascular disease by reducing serum cholesterol concentrations and blood pressure and by inhibiting platelet aggregation. However, most of these studies have been performed in hypercholesterolemic subjects or in animal models. We performed a 13-wk study in normolipidemic subjects who ingested 5 mL of aged garlic extract per day. Dietary supplementation significantly inhibited both the total percentage and initial rate of platelet aggregation. We conclude that AGE, when taken as a dietary supplement by normolipidemic subjects, may be beneficial in protecting against cardiovascular disease as a result of inhibiting platelet aggregation. (Rahman K& Billington D, J Nutr, 130(11): 2662, 2000)
Due to the high incidence of atherosclerosis in diabetes, the present study investigated the effect of garlic extract on the coronary vascular ultrastructural changes. At present, garlic extract may open the new era in the medicinal use of garlic to prevent diabetic cardiovascular complications. (Patumraj S, et al, Drug Deliv, 7(2): 91, 2000)
Garlic has been shown to have applications as an antimicrobial, antithrombotic, antitumor, hypolipidaemic, antiarthritic and hypoglycemic agent. In particular, the use of garlic in the treatment and prevention of cardiovascular disease and cancer is an area of considerable investigation and interest. (Ali M, Prostaglandins Leukot Essent Fatty Acids, 62(2): 55, 2000)
Extensive evidence points to the ability of allyl sulfides from garlic to suppress tumor proliferation both in vitro and in vivo. Both concentration and duration of exposure can increase the antiproliferative effects of lipid- and water-soluble allyl sulfides. Part of their antiproliferative effects may relate to an increase in membrane fluidity and a suppression of integrin glycoprotein IIb-IIIa mediated adhesion. Allyl sulfides are also recognized for their ability to suppress cellular proliferation by blocking cells in the G2/M phase and by the induction of apoptosis. This increase in the G2/M and apoptotic cell populations correlates with elevated cellular peroxide production. The composition of the entire diet and genetic/epigenetic factors will likely determine the true benefits that might arise from allyl sulfur compounds from garlic. (Knowles L & Milner J, Drug Metabol Drug Interact, 17(1-4): 81, 2000)
Six different mixtures of garlic distilled oils were been assayed against a number of yeasts (C. albicans, C. tropicalis and B. capitatus), gram-positive bacteria (S. aureus and B. subtilis) and gram-negative bacteria (P. aeruginosa and E. coli). Results support a specific antifungal more than an antibacterial activity. (Avato P, Phytomedicine, 7(3): 239, 2000)
The antiplatelet activity of methyl allyltrisulfide (MATS), a component commonly present in steam-distilled garlic oil, has been demonstrated by the authors. In addition, our recent findings that to a promyelocytic leukemia cell HL60, Allium oils shows marked anti-neoplastic effects representing both growth suppression and differentiation activities. (Ariga T, Biofactors, 13(1-4): 251, 2000)
In the circulation of sickle cell anemia patients, a certain population of erythrocytes has an elevated density. These abnormally dense cells are believed to be at the root of the painful crisis and anemia of the patients. We have found that aged garlic extract (AGE) as well as its components with antioxidant activity, inhibited the formation of dense cells in vitro. The degree of inhibition in vitro by antioxidants taken orally may be related to their efficacy in inhibiting dense cell formation in the patients. (Ohnishi S & Ohnishi T, J Nutr, 131(3): 1085S, 2001)
The antibacterial activity of garlic powder was tested by using garlic bulbs post-harvested 1 year. The use of powder from fresh garlic was more effective for antibacterial activity than that from old garlic. The antibacterial activity was resistant to heat treatment of 100 degrees C for 20 min. The antibacterial activity was shown against pathogenic bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), Salmonella enteritidis, and Candida albicans. Thus, the practical use of garlic powder is expected to prevent bacteria-caused food poisoning. (Sasaki J. et al, J Nutr Sci Vitaminol (Tokyo), 45(6): 785, 1999)
Allicin, one of the active principles of freshly crushed garlic homogenates, has a variety of antimicrobial activities. Allicin in its pure form exhibits i) antibacterial activity against a wide range of Gram-negative and Gram-positive bacteria, including multidrug-resistant enterotoxicogenic strains of Escherichia coli; ii) antifungal activity, particularly against Candida albicans; iii) antiparasitic activity, including some major human intestinal protozoan parasites such as Entamoeba histolytica and Giardia lamblia; and iv) antiviral activity. (Ankri S & Mirelman D, Microbes Infect, 1(2): 125, 1999)
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Leek has been known and used for centuries for its medicinal properties, although nowadays it is used mainly as food or flavor.
