Allium vegetables and upper aerodigestive tract cancers: a meta-analysis of observational studies

Mol Nutr Food Res. 2016 Jan;60(1):212-22. doi: 10.1002/mnfr.201500587. Epub 2015 Nov 9.


Scope: To provide updated quantitative overall estimations of the relation between total allium, garlic, and onion intake on the risk of cancer of the upper aerodigestive tract (UADT).

Methods and results: We combined data of published observational studies (21 case-control and four cohort studies), using a meta-analytic approach and random effects models. The overall relative risks (RR) and 95% confidence intervals (CIs) for the squamous cell carcinoma of the UADT were 0.79 (95% CI 0.56-1.11) for total allium, 0.74 (95% CI 0.57-0.95) for garlic, and 0.72 (95% CI 0.57-0.91) for onion for the highest versus the lowest consumption. The inverse relation was apparently stronger in case-control studies (RR 0.56, 95% CI 0.38-0.83 for total allium), in Chinese studies (RR 0.67, 95% CI 0.45-0.98 for garlic intake), and for esophageal than for head and neck cancers. Apparently, there was no relation between allium vegetable intake and adenocarcinoma of the esophagus.

Conclusion: We found a moderate inverse association between allium vegetable intake and the risk of squamous cell carcinoma of the UADT in case-control studies. The relation was unclear in cohort studies and for adenocarcinoma of the esophagus.

Keywords: Allium vegetables; Diet; Epidemiology; Squamous cell carcinoma; Upper aerodigestive tract cancer.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allium / chemistry*
  • Databases, Factual
  • Diet
  • Esophageal Neoplasms / epidemiology*
  • Gastrointestinal Neoplasms / epidemiology*
  • Head and Neck Neoplasms / epidemiology*
  • Humans
  • Observational Studies as Topic
  • Risk Factors