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Garlic

Plants do not have immune systems to defend themselves against the bacteria, fungi, viruses and yeasts that attack them. Their defense is direct chemical warfare. Their weapons are antibiotics, antivirals and fungicides that they manufacture internally. Their success is demonstrated by the fact that you see healthy growing plants everywhere.

In the case of garlic, one of the main active ingredients is a thiosulfinate compound called allicin. The manufacture of allicin is triggered by the release of enzymes by breaking the cell walls of the garlic plant. Allicin is the pungent, hot, stinky stuff that makes garlic special. In addition to allicin, garlic contains over 100 other beneficial nutrients. These include beta-carotene, folate, beta-sitosterol, ferulic acid, geraniol, oleanolic acid, P-coumaric acid, rutin, quercetin, thiamine, niacin, vitamin c, cysteine, zinc, calcium, magnesium, manganese, selenium, and others.

Garlic is an Anti-biotic and Anti-viral

In vitro (in laboratory cultures) studies demonstrate that garlic has antibacterial, antiviral, and antifungal activity. In one Clinical study, one capsule daily of an allicin-containing garlic supplement was tested on a group of 146 volunteers (Josling P 2001). Over several months half the group received the garlic while the other half got a placebo. The placebo group had 63 percent more common cold infections than the garlic group. In addition, those in the garlic group who did catch a cold had symptoms for an average of only 1.52 days, compared with 5.01 days for the placebo group. The doctors who conducted this garlic study concluded, "An allicin-containing supplement can prevent attack by the common cold virus."

Garlic in Herpes Virus Infections

While garlic has demonstrated in vitro anti-viral activity against many viruses including HSV-1 and HSV-2, clinical trials on humans have not been performed. Garlic's in vitro success against these viruses and its demonstrated in vivo effectiveness against the common cold virus suggests that it may be effective against the herpes viruses in humans as well. However, this hypothesis has not been clinically tested and, until it is, such claims cannot be made.

Garlic Lowers Blood Pressure

There is some evidence that garlic is mildly hypotensive in humans. Researchers at the University of Mississippi and in Turkey performed clinical tests on the effectiveness of garlic in reducing blood pressure. They found that garlic reduced systolic blood pressure by at least 9 mmHg and diastolic blood pressure by at least 5 mmHg. The effect was most noted in subjects with high blood pressure and high cholesterol. No hypotensive effect was observed in patients with normal blood pressure.

Garlic for Lowering Cholesterol

There is contradictory evidence as to whether garlic actually lowers cholesterol and triglyceride levels or not. The contradictions appear to arise from the use of different dosages, forms of garlic and other procedural differences. However, most findings showed that garlic slightly lowered blood cholesterol, LDL cholesterol and triglycerides with a consistent lowering of blood lipids seen in studies that used aged garlic extract (kyolic) as the supplement.

Research has demonstrated that garlic inhibits the peroxidation of lipids. This, in turn, prevents LDL cholesterol from being oxidized into harmful compounds. Garlic also lowers homocysteine levels. Recent research has identified homocysteine as a major culprit in heart disease, osteoporosis, alzheimers and several other degenerative diseases.

Garlic in Atherosclerosis

Garlic reduces platelet aggregation, thrombin formation, platelet adhesion to fibrinogen and the risk of thrombosis. Garlic's effects are attributed to allicin, ajoene, and other organosulfur constituents in the herb. A recent study on garlic confirms that it exhibits powerful fibrinolytic activity both in vitro and in vivo. In this study, it acted as an anticoagulant by downregulating thrombin formation. These effects reduce the formation of atherosclerotic plaque.

In one study, patients with atherosclerosis had higher plasma levels of the oxidant MDA ( malondialdehyde ) and lower plasma levels of the antioxidant enzyme glutathione peroxidase compared to the control group. However, those patients who consumed 1 ml/kg of garlic extract had significantly lowered MDA levels even in the absence of changes in antioxidant enzyme activities. In addition, the researchers found the presence of oxidant stress in blood samples from atherosclerosis patients, but ingesting garlic extract prevented oxidation reactions by eliminating this oxidant stress.

Garlic and Men's Health

Garlic may reduce the risk of prostate cancer, according to a recent study. Researchers surveyed 238 men with prostate cancer and 471 healthy controls in Shanghai, China to determine their eating habits. The risk of prostate cancer declined by more than 33 percent in men who consumed small amounts of onions, garlic, scallions, shallots and leeks each day. Men who consumed 2 grams of garlic daily experienced a 50 percent decease in prostate cancer risk.

Another study done with rats demonstrated that garlic supplementation in combination with a high protein diet increased testosterone levels.

Anti-Cancer Properties of Garlic

Modern epidemiological studies, well correlated with laboratory investigations, corroborate the evidence that higher intake of garlic and its relatives is correlated with reduced risk of several cancers. The mechanisms proposed to explain the cancer-preventive effects of garlic include inhibition of tumor mutagenesis, modulation of enzyme activities, and effects on cell proliferation and tumor growth. Several garlic compounds, including allicin, induce apoptosis (programmed cell death) in various malignant human cells. These include breast, colorectal, hepatic, prostate, and lymphoma cells. A growing number of clinical studies are examining the properties of ajoene, one of the major components of purified garlic. Researchers are investigating ajoene in part because it is more chemically stable than allicin. The list of cancers responding to garlic treatment or supplementation continues to grow.

Garlic Dosage

People who wish to consume garlic and have no aversion to its odor can chew from one to two whole cloves of raw garlic daily. In certain regions of China up to eight cloves of raw garlic are consumed per day. For those who prefer it with less odor, enteric-coated tablets or capsules with approximately 1.3% allacin are available. Clinical trials have used 600-900 mg (delivering approximately 5-6 mg of allicin ) per day in two or three divided amounts. Aged-garlic extracts have been studied in amounts ranging from 2.4-7.2 grams per day.

Garlic Side Effects and Drug Interactions

Garlic has anti-coagulant properties. Anyone with a bleeding disorder or taking anti-coagulant or anti-platlett medications should consult their doctor before consuming garlic. Examples of such medications include indomethacin, dipyridamole, and aspirin. Anyone anticipating surgery, child birth, etc. should avoid garlic.

Garlic may lower blood sugar considerably and may potentize the effect of certain anti-diabetic medications. Medications from this class include chlorpropamide, glimepiride, and glyburide. When using garlic with these medications, blood sugars must be followed closely and garlic use should be used under your doctor's advise.

Garlic may reduce blood levels of protease inhibitors. Protease Inhibitors are a class of drugs used to treat people with the human immunodeficiency virus (HIV). They include indinavir, ritinavir, and saquinavir.

It is hhypothesized by some that garlic may behave similarly to a class of cholesterol lowering medications called statins and to a class of blood pressure lowering medications called ACE inhibitors. Examples of these medications include atorvastatin, pravastatin, lovastatin, enalapril, captopril, and lisinopril. Possible interactions with these medications has not been tested.

Other side effects from garlic may include upset stomach, bloating, bad breath, and body odor.

Garlic is considered to have very low toxicity and is listed as Generally Recognized as Safe (GRAS) by the Food and Drug Administration (FDA) of the United States.

More research with better-designed studies is needed in order to fully assess the safety and effectiveness of garlic and to determine the most appropriate dose and form.

Recommended Garlic Products

The most direct way to use garlic is to simply eat the cloves directly. To get the benefits from eating raw garlic, it must be chewed thoroughly to release the allacin. This can be very "hot" and spicey. This combined with the odor can discourage the less dedicated. Alternatively, garlic is available in supplement form.

Optimized Garlic From the Life Extension Foundation

Garlic Related Articles in Life Extension Magazine

How Aged Garlic Extract Can Slash Heart Disease Risk, Scientifically reviewed by Dr. Gary Gonzalez, MD, in May 2022. Written by: Michael Downey, Health & Wellness Author.

Garlic, Scientifically reviewed by: Holli Ryan, RD, LD/N, in March 2021. Written by: Life Extension Editorial Staff.

Garlic extract, Gastritis, Melatonin, and Menopause, Scientifically reviewed by Dr. Gary Gonzalez, MD, in May 2022. Written by: Life Extension Editorial Staff.

Phytonutrients, Scientifically reviewed by: Dr. Gary Gonzalez, MD, in January 2021. Written by: Life Extension Editorial Staff.

Garlic References

Click to Expand References

1. Riddle JM. Garlic's history as a medicine. Paper presented at: American Herbal Products Association International Carlic Symposium; July 31, 2001.

2. Heber D. Vegetables, fruits and phyto-estrogens in the prevention of diseases. J Postgrad Med. 2004 Apr;50(2):145-9.

3. Atmaca G. Antioxidant effects of sulfur-containing amino acids. Yonsei Med J. 2004 Oct 31;45(5):776-88.

4. Kempaiah RK, Srinivasan K. Influence of dietary curcumin, capsaicin and garlic on the antioxidant status of red blood cells and the liver in high-fat-fed rats. Ann Nutr Metab. 2004 September ;48(5):314-20.

5. Kempaiah RK, Srinivasan K. Antioxidant status of red blood cells and liver in hypercholesterolemic rats fed hypolipidemic spices. Int J Vitam Nutr Res. 2004 May;74(3):199-208.

6. Perez-Severiano F, Rodriguez-Perez M, Pedraza-Chaverri J, et al. S-Allylcysteine, a garlic-derived antioxidant, ameliorates quinolinic acid-induced neurotoxicity and oxidative damage in rats. Neurochem Int. 2004 Dec;45(8):1175-83.

7. Maldonado PD, Barrera D, Rivero I, et al. Antioxidant S-allylcysteine prevents gentamicin-induced oxidative stress and renal damage. Free Radic Biol Med. 2003 Aug 1;35(3):317-24.

8. Sovova M, Sova P. Pharmaceutical importance of Allium sativum L. 5. Hypolipemic effects in vitro and in vivo. Ceska Slov Farm. 2004 May;53(3):117-23.

9. Durak A, Ozturk HS, Olcay E, Guven C. Effects of garlic extract supplementation on blood lipid and antioxidant parameters and atherosclerotic plaque formation process in cholesterol-fed rabbits. J Herb Pharmcother. 2002;2(2):19-32.

10. Budoff MJ, Takasu J, Flores FR, et al. Inhibiting progression of coronary calcification using aged garlic extract in patients receiving statin therapy: a preliminary study. Prev Med. 2004 Nov;39(5):985-91.

11. Wilburn AJ, King DS, Glisson J, Rockhold RW, Wofford MR. The natural treatment of hypertension. J Clin Hypertens.(Greenwich.) 2004 May;6(5):242-8.

12. Durak I, Kavutcu M, Aytac B, et al. Effects of garlic extract consumption on blood lipid and oxidant/antioxidant parameters in humans with high blood cholesterol. J Nutr Biochem. 2004 Jun;15(6):373-7.

13. Sengupta A, Ghosh S, Bhattacharjee S. Allium vegetables in cancer prevention: an overview. Asian Pac J Cancer Prev. 2004 Jul;5(3):237-45.

14. Hassan HT. Ajoene (natural garlic compound): a new anti-leukaemia agent for AML therapy. Leuk Res. 2004 Jul;28(7):667-71.

15. Ledezma E, Apitz-Castro R, Cardier J. Apoptotic and anti-adhesion effect of ajoene, a garlic derived compound, on the murine melanoma B16F10 cells: possible role of caspase-3 and the alpha(4)beta(1) integrin. Cancer Lett. 2004 Mar 31;206(1):35-41.

16. Tilli CM, Stavast-Kooy AJ, Vuerstaek JD, et al. The garlic-derived organosulfur component ajoene decreases basal cell carcinoma tumor size by inducing apoptosis. Arch Dermatol Res. 2003 Jul;295(3):117-23.

17. Xu B, Monsarrat B, Gairin JE, Girbal-Neuhauser E. Effect of ajoene, a natural antitumor small molecule, on human 20S proteasome activity in vitro and in human leukemic HL60 cells. Fundam Clin Pharmacol. 2004 Apr;18(2):171-80.

18. Lu HF, Sue CC, Yu CS, et al. Diallyl disulfide (DADS) induced apoptosis undergo caspase-3 activity in human bladder cancer T24 cells. Food Chem Toxicol. 2004 Oct;42(10):1543-52.

19. Wu CC, Chung JG, Tsai SJ, Yang JH, Sheen LY. Differential effects of allyl sulfides from garlic essential oil on cell cycle regulation in human liver tumor cells. Food Chem Toxicol. 2004 Dec;42(12):1937-47.

20. Sengupta A, Ghosh S, Bhattacharjee S, Das S. Indian food ingredients and cancer prevention - an experimental evaluation of anticarcinogenic effects of garlic in rat colon. Asian Pac J Cancer Prev. 2004 Apr;5(2):126-32.

21. Zlotogorski HA, Littner M. Potential risks, adverse effects and drug interactions associated with herbal medicine in dental patients. Refuat Hapeh Vehashinayim. 2004 Apr;21(2):25-41, 97.

22. Ciocon JO, Ciocon DG, Galindo DJ. Dietary supplements in primary care. Botanicals can affect surgical outcomes and follow-up. Geriatrics. 2004 Sep;59(9):20-4.

23. Hsing AW, Chokkalingam AP, Gao YT, Madigan MP, Deng J, Gridley G, Fraumeni JF Jr. Allium vegetables and risk of prostate cancer: a population-based study. J Natl Cancer Inst. 2002 Nov 6;94(21):1648-51

24. Durak I, Aytac B, Atmaca Y, Devrim E, Avci A, Erol C, Oral D. Effects of garlic extract consumption on plasma and erythrocyte antioxidant parameters in atherosclerotic patients. Life Sci. 2004 Sep 3;75(16):1959-66.

25. Saravanan G, Prakash J. Effect of garlic (Allium sativum) on lipid peroxidation in experimental myocardial infarction in rats. J Ethnopharmacol. 2004 Sep;94(1):155-8.

26. Weber ND, Andersen DO, et al. In vitro virucidal effects of Allium sativum (garlic) extract and compounds. Planta Med. 1992 Oct;58(5):417-23.

27. Guo NL, Lu DP, et al. Demonstration of the anti-viral activity of garlic extract against human cytomegalovirus in vitro. Chin Med J (Engl). 1993 Feb;106(2):93-6.

28. Josling P. Preventing the common cold with a garlic supplement: A double-blind, placebo-controlled survey. Adv Ther . 2001 Jul;18(4):189-93.

29. Kyo E, Uda N, et al. Immunomodulatory effects of aged garlic extract. J Nutr . 2001 Mar;131(3s):1075S - 9S.

30. Koch HP, Lawson LD (eds). Garlic: The Science and Therapeutic Application of Allium sativaum L and Related Species, 2d ed. Baltimore: Williams and Wilkins, 1996, 62-4.

31. Warshafsky S, Kamer R, Sivak S. Effect of garlic on total serum cholesterol: A meta-analysis. Ann Int Med 1993;119:599-605.

32. Silagy C, Neil A. Garlic as a lipid-lowering agent-a meta-analysis. J R Coll Phys London 1994;28:39-45.

33. Neil HA, Silagy CA, Lancaster T, et al. Garlic powder in the treatment of moderate hyperlipidaemia: A controlled trial and a meta-analysis. J R Coll Phys 1996;30:329-34.

34. McCrindle BW, Helden E, Conner WT. Garlic extract therapy in children with hypercholesterolemia. Arch Pediatr Adolesc Med 1998;152:1089-94.

35. Isaacsohn JL, Moser M, Stein EA, et al. Garlic powder and plasma lipids and lipoproteins. Arch Intern Med 1998;158:1189-94.

36. Berthold HK, Sudhop T, von Bergmann K. Effect of a garlic oil preparation on serum lipoproteins and cholesterol metabolism. JAMA 1998;279:1900-2.

37. Legnani C, Frascaro M, Guazzaloca G, et al. Effects of a dried garlic preparation on fibrinolysis and platelet aggregation in healthy subjects. Arzneim-Forsch Drug Res 1993;43:119-22.

38. Silagy CA, Neil HA. A meta-analysis of the effect of garlic on blood pressure. J Hyperten 1994;12:463-8.

39. Kleijnen J, Knipschild P, Ter Riet G. Garlic, onion and cardiovascular risk factors: A review of the evidence from human experiments with emphasis on commercially available preparations. Br J Clin Pharmacol 1989;28:535-44.

40. Koscielny J, Klüendorf D, Latza R, et al. The antiatherosclerotic effect of Allium sativum. Atherosclerosis 1999;144:237-49.

41. Hughes BG, Lawson LD. Antimicrobial effects of Allium sativum L. (garlic), Allium ampeloprasum L. (elephant garlic) and Allium cepa L. (onion), garlic compounds and commercial garlic supplement products. Phytother Res 1991;5:154-8.

42. Dorant E, van den Brandt PA, Goldbohm RA, et al. Garlic and its significance for the prevention of cancer in humans: A critical review. Br J Cancer 1993;67:424-9.

43. Fleishauer AT, Poole C, Arab L. Garlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers. Am J Clin Nutr 2000;72:1047-52.

44. Brown DJ. Herbal Prescriptions for Better Health. Rocklin, CA: Prima Publishing, 1996, 97-109.

45. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 134.

46. Burnham BE: Garlic as a possible risk for postoperative bleeding. Plast Reconst Surg 1995; 95:213.

47. Rose KD, Croissant PD, Parliament CF et al: Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: a case report. Neurosurg 1990; 26:880-882.

48. Sunter W: Warfarin and garlic. Pharm J 1991; 246:722.

49. Piscitelli SC, Burstein, Welden et al: Garlic supplements decrease saquinavir plasma concentrations [abstract]. 8th Conference on Retroviruses and Opportunistic Infections, Feb 4-8, 2001, Chicago, Illinois. Abstract 743.

50. Gurley BJ, Gardner SF, Hubbard MA et al: Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002; 72(3):276-287.

51. Apitz-Castro R, Escalante J, Vargas R et al: Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, forskolin, indomethacin, and dypiridamole on human platelets. Thromb Res 1986; 42:303-311.


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