Background
- Garlic is a culinary herb that is widely used for the treatment and prevention of cardiovascular disease and cancer. Numerous controlled trials have examined the effects of oral garlic on serum lipids. Long-term effects on lipids or cardiovascular morbidity and mortality remain unknown. Other preparations (such as enteric-coated or raw garlic) have not been well studied.
- Small reductions in blood pressure (
- Numerous case-control/population-based studies suggest that regular consumption of garlic (particularly unprocessed garlic) may reduce the risk of developing several types of cancer, including gastric and colorectal malignancies. However, prospective controlled trials are lacking.
- Multiple cases of bleeding have been associated with garlic use, and caution is warranted in patients at risk of bleeding or prior to some surgical/dental procedures. Garlic does not appear to significantly affect blood glucose levels.
References
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to . Selected references are listed below.
- Ashraf R, Aamir K, Shaikh AR, et al. Effects of garlic on dyslipidemia in patients with type 2 diabetes mellitus. J Ayub Med Coll Abbottabad 2005 Jul-Sep;17(3):60-4.
View Abstract - Gail MH, You WC. A factorial trial including garlic supplements assesses effect in reducing precancerous gastric lesions. J Nutr 2006 Mar;136(3 Suppl):813S-815S.
View Abstract - Hajheydari Z, Jamshidi M, Akbari J, et al. Combination of topical garlic gel and betamethasone valerate cream in the treatment of localized alopecia areata: a double-blind randomized controlled study. Indian J Dermatol Venereol Leprol 2007 Jan-Feb;73(1):29-32.
View Abstract - Josling P. Preventing the common cold with a garlic supplement: a double-blind, placebo-controlled survey. Adv Ther 2001;18(4):189-193.
View Abstract - Kim, J. Y. and Kwon, O. Garlic intake and cancer risk: an analysis using the Food and Drug Administration's evidence-based review system for the scientific evaluation of health claims. Am.J Clin Nutr. 2009;89(1):257-264.
View Abstract - McNulty CA, Wilson MP, Havinga W, et al. A pilot study to determine the effectiveness of garlic oil capsules in the treatment of dyspeptic patients with Helicobacter pylori. Helicobacter 2001;6(3):249-253.
View Abstract - Meher S, Duley L. Garlic for preventing pre-eclampsia and its complications. Cochrane Database Syst Rev 2006 Jul 19;3:CD006065.
View Abstract - Reinhart, K. M., Talati, R., White, C. M., and Coleman, C. I. The impact of garlic on lipid parameters: a systematic review and meta-analysis. Nutr.Res.Rev. 2009;22(1):39-48.
View Abstract - Ried, K., Frank, O. R., Stocks, N. P., Fakler, P., and Sullivan, T. Effect of garlic on blood pressure: a systematic review and meta-analysis. BMC.Cardiovasc.Disord. 2008;8:13.
View Abstract - Sabitha P, Adhikari PM, Shenoy SM, et al. Efficacy of garlic paste in oral candidiasis. Trop Doct 2005;35(2):99-100.
View Abstract - Siegel G. Long-term effect of garlic in preventing arteriosclerosis - results of two controlled clinical trials. Eur Phytojournal 2001;Symposium posters(1):1.
- Takasu J, Uykimpang R, Sunga MA, et al. Aged garlic extract is a potential therapy for sickle-cell anemia. J Nutr 2006 Mar;136(3 Suppl):803S-805S.
View Abstract - Tanaka S, Haruma K, Yoshihara M, et al. Aged garlic extract has potential suppressive effect on colorectal adenomas in humans. J Nutr 2006 Mar;136(3 Suppl):821S-826S.
View Abstract - You WC, Brown LM, Zhang L, et al. Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions. J Natl Cancer Inst 2006 Jul 19;98(14):974-83.
View Abstract - Wojcikowski K, Myers S, Brooks L. Effects of garlic oil on platelet aggregation: a double-blind placebo-controlled crossover study. Platelets 2007 Feb;18(1):29-34.
View Abstract