Mediterranean diet adherence reduces colorectal cancer incidence

Adherence to a Mediterranean diet is inversely associated with incidence of colorectal cancer (CRC), but not with overall mortality or CRC-specific mortality among those diagnosed with the disease, according to the results of a meta-analysis.

“Mounting epidemiologic studies have investigated the potential inverse association between Mediterranean diet adherence and CRC incidence and mortality,” the investigators said.

The investigators sought to assess the association of Mediterranean diet adherence with CRC incidence and mortality in this study. They searched the databases of PubMed, Embase, and Web of Science to identify eligible studies up to September 2019. Summary risk ratios (RRs) and 95 percent confidence intervals (CIs) were estimated using a random-effects model.

Thirteen studies met the eligibility criteria, of which nine reported CRC incidence and five CRC mortality. The summary RR of CRC incidence was 0.90 (95 percent CI, 0.84–0.96) for the highest vs lowest Mediterranean diet adherence and 0.96 (95 percent CI, 0.94–0.99) per 2-score increase in Mediterranean diet adherence.

In terms of specific cancers, the summary RRs for the highest vs lowest Mediterranean adherence were 0.82 (95 percent CI, 0.71–0.95) for rectal cancer, 0.94 (95 percent CI, 0.87–1.02) for proximal colon cancer, and 0.91 (95 percent CI, 0.79–1.04) for distal colon cancer.

Statistical significance was not achieved in neither the summary HR of overall mortality for the highest vs lowest pre- and postdiagnosis Mediterranean diet adherence nor the summary HR of CRC-specific mortality for the highest vs lowest prediagnosis Mediterranean diet adherence.