Low level of selenium predicts high incidence of colorectal cancer

To investigate the relationship between selenium and its role in the incidence of colorectal cancer (CRC). A systematic review and meta-analysis was conducted by searching PubMed, Embase, and Web of Science databases to identify studies evaluating the association between selenium exposure and CRC risk. Studies assessing selenium by serum concentration, dietary intake, or tissue level were eligible. The relative risk (RR) and 95% confidence interval (CI) were calculated using the random effects model. A total of 16 studies were included, and the overall pooled analysis showed that higher selenium exposure was associated with a reduced risk of CRC (RR = 0.81, 95% CI = 0.72–0.91). When stratified by study design, significant inverse associations were observed in both cohort studies (RR = 0.84, 95% CI = 0.78–0.90) and case-control studies (RR = 0.76, 95% CI = 0.64–0.92). Subgroup analyses revealed significant inverse associations in European (RR = 0.81, 95% CI = 0.67–0.98) and Oceanian (RR = 0.70, 95% CI = 0.56–0.87) populations, and in colon cancer (RR = 0.81, 95% CI = 0.68–0.97) but not rectal cancer. Dietary selenium intake showed a protective effect (RR = 0.74, 95% CI = 0.63–0.86), whereas serum and toenail selenium were not significantly associated with CRC risk. Collectively, our findings indicate that selenium sufficiency is linked to a lower risk of colorectal cancer. The results emphasize the potential role of selenium status as a modifiable nutritional factor in colorectal cancer prevention and warrant further mechanistic and interventional research.