Garlic May Protect Against Colon Cancer

ADELAIDE, AustraliaA research team from the University of South Australia examined studies from the last decade and found consistent scientific evidence that garlic may protect against development of colorectal cancer (CRC). In their new study, published in the Journal of Nutrition (2007;137:2264-9), researchers ranked studies from the last decade from level I to level V, according to study designs, and assessed the quality of each study based on a set of criteria used by the National Health and Medical Research Council in Australia. One randomized controlled trial (RCT, level II) reported a 29-percent reduction in size and number of colon adenomas in CRC patients taking aged garlic extract. Five of eight case control/cohort studies (level III) suggested a protective effect of high intake of raw or cooked garlic; two of the studies suggested a protective effect for the distal colon. A meta-analysis (level III) of seven of these studies confirmed the inverse association, with a 30-percent reduction in relative risk. 11 animal studies (level V) demonstrated a significant anticarcinogenic effect of garlic and/or its active constituents.