Garlic consumption and colorectal cancer risk in the CPS-II Nutrition Cohort

Marjorie L. McCullough, Eric J. Jacobs, Roma Shah, Peter T. Campbell, Susan M. Gapstur

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Purpose The World Cancer Research Fund/American Institute for Cancer Research identified a probable role for garlic in colorectal cancer prevention based on preclinical evidence and epidemiologic studies, but prospective data are limited. The purpose of this paper was to contribute additional evidence on this topic for men and women in a large prospective cohort study. Methods In 1999, 42,824 men and 56,876 women in the Cancer Prevention Study II Nutrition Cohort completed a questionnaire with information on dietary garlic consumption. Garlic supplement use was assessed in 2001. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard rate ratios (HRs) and 95 % confidence intervals (CIs). Results During 7 years of follow-up, 579 men and 551 women were diagnosed with colorectal cancer. Among men, daily garlic consumption was associated with a nonsignificant higher colorectal cancer risk (HR = 1.04, 95 % CI 0.99-1.08 for each additional clove or ''4 shakes'' of garlic per week), whereas the association was borderline inverse in women (HR = 0.95, 95 % CI 0.91-1.00, p heterogeneity by sex = 0.03). Garlic supplement use was not related to a lower risk of colorectal cancer, and in men, former use was associated with a higher risk of colorectal cancer (HR = 1.85, 95 % CI 1.13-3.03). Conclusions These results provide weak support for a role of dietary garlic consumption in colorectal cancer prevention in women, but a possible increased risk in men. Further research is needed to confirm different associations by sex.

Original languageEnglish (US)
Pages (from-to)1643-1651
Number of pages9
JournalCancer Causes and Control
Issue number10
StatePublished - Oct 2012
Externally publishedYes


  • Allium vegetables
  • Colorectal neoplasms
  • Diet
  • Garlic
  • Supplements

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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