High intake of cruciferous vegetables reduces the risk of gastrointestinal cancers: results from observational studies.

The relationship between cruciferous vegetables (CV) and the risk of gastrointestinal (GI) cancers has been extensively investigated. However, epidemiologic investigations have produced inconsistent results. This meta-analysis investigated the association between CV intake and the risk of GI cancers. Due to the heterogeneity, fixed- or random-effects models were used for the analyses. The final analysis included 81 articles covering 89 studies. In comparison to the lowest consumption categories, the highest consumption categories of CV were associated with a lower risk for all GI cancers [rate ratio (RR): 0.81, 95% confidence interval (95% CI) 0.76-0.87]. Compared to a CV intake of 75 g/day, subjects with CV intake <75 g/day experienced a 7% reduction in risk (RR: 0.93; 95% CI: 0.84-0.96) for each 50 g increase in consumption. A negative correlation was identified between CV intake and the risk of esophageal cancer, gastric cancer, liver cancer, pancreatic cancer, and colorectal cancer (CRC), but not gallbladder cancer (RR: 0.70; 95% CI: 0.38-1.27). High intake of broccoli and cabbage was associated with a decreased risk of gastric cancer (RR: 0.64; 95% CI: 0.47-0.87) and gallbladder cancer (RR: 0.46; 95% CI: 0.29-0.75). These results confirm the association between high intake of CV with a reduced risk of GI cancers.