Consumption of garlic and risk of colorectal cancer: an updated meta-analysis of prospective studies.
Hu JY1, Hu YW1, Zhou JJ1, Zhang MW1, Li D1, Zheng S1.
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Abstract
AIM:
To conduct an updated meta-analysis of prospective studies addressing the association between garlic consumption and colorectal cancer.
METHODS:
Eligible cohort studies were identified by searching MEDLINE (PubMed) and screening the references of related articles published up to October 2013. Meta-analyses were conducted for colorectal cancer in relation to consumption of raw and cooked (RC) garlic and garlic supplements, separately. The summary relative risks (RR) with 95%CI were calculated using fixed-effects or random-effects model depending on the heterogeneity among studies.
RESULTS:
A total of 5 prospective cohort studies were identified. In contrast to the previous meta-analysis, no significant associations were found between consumption of RC garlic (RR: 1.06; 95%CI: 0.95-1.19) or garlic supplements (RR: 1.12; 95%CI: 0.96-1.31) and risk of colorectal cancer. A non-significant protective effect of garlic supplement intake against colorectal cancer was observed in females (RR: 0.84; 95%CI: 0.64-1.11), but the opposite was the case in males (RR: 1.24; 95%CI: 0.96-1.59).
CONCLUSION:
Consumption of RC garlic or garlic supplements is not significantly associated with reduced colorectal cancer risk.
KEYWORDS:
Cancer prevention; Colorectal cancer; Garlic; Garlic supplement; Meta-analysis