Authors' objectives:

This report addresses three areas: 1. Effects on cardiovascular-related disease and factors such as lipids, blood pressure, glucose, atherosclerosis, and thrombosis. 2. Any protective associations with cancer. 3. Clinical adverse effects.

Authors' recommendations: There are insufficient data to draw conclusions regarding garlic's effects on clinical cardiovascular outcomes such as claudication and myocardial infarction. Garlic preparations may have small, positive, short-term effects on lipids; whether effects are sustainable beyond 3 months is unclear. Consistent reductions in blood pressure with garlic were not found, and no effects on glucose or insulin sensitivity were found. Some promising effects on antithrombotic activity were reported, but few data are available for definitive conclusion. Using any garlic supplement for less than 3 to 5 years was not associated with decreased risks of breast, lung, gastric, colon, or rectal cancer. Some case-control studies suggest that high dietary garlic consumption may be associated with decreased risks of laryngeal, gastric, colorectal, and endometrial cancers, and adenomatous colorectal polyps. Multiple adverse effects, including breath and body odor, dermatitis, bleeding, abdominal symptoms, and flatulence have been reported. Whether adverse effects occur more commonly with certain preparations than others was not established. Furthermore, the causality of the adverse effects was not clear, except for breath and body odor, and the expected frequency of adverse effects was not determined.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/garlicsum.htm

Year Published: 2000

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)