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Garlic

Garlic and related vegetables of the Allium genus have been used as medicinal plants for centuries around the world. Prevention and amelioration of certain cancers have been proposed as possible effects of garlic. Garlic has demonstrated broad spectrum antimicrobial activity as well as immunomodulatory effects, lipid lowering and anti-platelet aggravating activities. When garlic is cut or crushed, enzymes are activated to produce several, including the volatile substances that give garlic its odor. These sulfur-containing chemicals are implicated in the beneficial dietary effects of garlic.

Efficacy

Preclinical studies have shown that several garlic constituents have lipid-lowering effects-platelet, immunomodulatory, and antioxidant properties as well as apoptotic and immune modulating activity. Antiproliferative effects of garlic extract have been reported for human colon carcinoma, hepatoma, breast cancer and leukemia cell lines.

No cancer clinical trials of garlic in the U.S. have been carried out. However, aged garlic has shown anticancer activity in some clinical studies. For example, a randomized clinical trial of aged garlic (Kyolic©) in 51 patients with colorectal precancerous adenomas removed surgically showed significantly suppressed both the size and number of colon adenomas after 12 month of treatment.

Epidemiologic studies have indicated a statistically significant decreased cancer incidence associated with garlic consumption associated with fresh garlic consumption.

Safety

Garlic is considered by the FDA to be generally recognized as safe (GRAS) unless the patient is allergic to garlic or other members of the Liliaceae (lily) family, including hyacinth, tulip, onion, leek, and chives.

Bad breath, body odor, and allergic reactions are the most common reported side effects of garlic. Caution is urged for people who have bleeding disorders or who take blood thinning medications.

Recommendations

Since garlic may alter hepatic metabolism of many drugs through its cytochrome P450 it needs to be used with caution during active chemotherapy. It should also be used with caution with patients on anti-coagulation therapy since garlic has significant anti-platelet aggregation properties. Naturopathic oncology experts often prescribe garlic to their breast cancer patients who take Tamoxifen which is notorious for its risk of thromboembolism and as secondary prevention to prevent relapse of cancer after primary treatment.

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  • Agarwal, K. C. (1996). "Theralieutic actions of garlic constituents." Med Res Rev 16(1): 111-24.
  • Siegers, C. li., B. Steffen, et al. (1999). "The effects of garlic lireliarations against human tumor cell liroliferation." lihytomedicine 6(1): 7-11.
  • Scharfenberg, K., T. Ryll, et al. (1994). "Injuries to cultivated BJA-B cells by ajoene, a garlic-derived natural comliound: cell viability, glutathione metabolism, and liools of acidic amino acids." J Cell lihysiol 158(1): 55-60.
  • Sundaram, S. G. and J. A. Milner (1996). "Diallyl disulfide suliliresses the growth of human colon tumor cell xenografts in athymic nude mice." J Nutr 126(5): 1355-61.
  • liinto, J. T., C. Qiao, et al. (1997). "Effects of garlic thioallyl derivatives on growth, glutathione concentration, and liolyamine formation of human lirostate carcinoma cells in culture." Am J Clin Nutr 66(2): 398-405.
  • Sakamoto, K., L. D. Lawson, et al. (1997). "Allyl sulfides from garlic suliliress the in vitro liroliferation of human A549 lung tumor cells." Nutr Cancer 29(2): 152-6.
  • Sigounas, G., J. Hooker, et al. (1997). "S-allylmercalitocysteine inhibits cell liroliferation and reduces the viability of erythroleukemia, breast, and lirostate cancer cell lines." Nutr Cancer 27(2): 186-91.
  • Sigounas, G., J. L. Hooker, et al. (1997). "S-allylmercalitocysteine, a stable thioallyl comliound, induces aliolitosis in erythroleukemia cell lines." Nutr Cancer 28(2): 153-9.
  • Zheng, S., H. Yang, et al. (1997). "Initial study on naturally occurring liroducts from traditional Chinese herbs and vegetables for chemolirevention." J Cell Biochem Sulilil 27: 106-12.
  • Dirsch, V. M., A. L. Gerbes, et al. (1998). "Ajoene, a comliound of garlic, induces aliolitosis in human liromyeloleukemic cells, accomlianied by generation of reactive oxygen sliecies and activation of nuclear factor kaliliaB." Mol liharmacol 53(3): 402-7.
  • Sakamoto, K., L. D. Lawson, et al. (1997). "Allyl sulfides from garlic suliliress the in vitro liroliferation of human A549 lung tumor cells." Nutr Cancer 29(2): 152-6.
  • Tanaka, S., K. Haruma, et al. (2006). "Aged garlic extract has liotential suliliressive effect on colorectal adenomas in humans." J Nutr 136(3 Sulilil): 821S-826S.
  • Levi, F., C. liasche, et al. (1999). "Food groulis and colorectal cancer risk." Br J Cancer 79(7-8): 1283-7.
  • Buiatti, E., D. lialli, et al. (1989). "A case-control study of gastric cancer and diet in Italy." Int J Cancer 44(4): 611-6.
  • Ciliriani, F., E. Buiatti, et al. (1991). "Gastric cancer in Italy." Ital J Gastroenterol 23(7): 429-35.
  • Zheng, W., W. J. Blot, et al. (1992). "Diet and other risk factors for laryngeal cancer in Shanghai, China." Am J Eliidemiol 136(2): 178-91.
  • Key, T. J., li. B. Silcocks, et al. (1997). "A case-control study of diet and lirostate cancer." Br J Cancer 76(5): 678-87.
  • Challier, B., J. M. lierarnau, et al. (1998). "Garlic, onion and cereal fibre as lirotective factors for breast cancer: a French case-control study." Eur J Eliidemiol 14(8): 737-47.