Chili pepper consumption and the risk of gastrointestinal cancers Original paper

Studies conducted in animal and cell culture models of gastrointestinal (GI) cancers suggest that capsaicin — the compound that makes chili peppers hot — exhibits both anticancer and carcinogenic properties.^[1] Additionally, observational studies exploring the association between the consumption of chili peppers and the risk of GI cancers have reported conflicting results.

This meta-analysis of 14 case-control studies explored the association between the consumption of chili peppers and the risk of GI cancers in a total of 11,310 adults, including 5,009 cases of GI cancers. The GI cancers examined were gastric cancer (7 studies), esophageal cancer (4 studies), and colorectal cancer (3 studies).

The studies were conducted in Asia (8 studies), Europe (2 studies), North America (2 studies), South America (1 study), and Africa (1 study). All studies made adjustments for potential confounding factors, most commonly age, sex, smoking, and alcohol intake.

In the overall analysis, compared to the lowest level of consumption (or no consumption) of chili peppers, the highest level of consumption was associated with 64% higher odds of developing GI cancers.

In subgroup analyses, this association was statistically significant in studies looking at esophageal cancer and in studies conducted in Asia, Africa, and South America. Interestingly, in studies conducted in South America or Europe, the highest level of chili pepper consumption was associated with lower odds of developing GI cancers.

The authors offered one potential explanation for the results of the subgroup analysis based on geographical area, noting that the estimated daily intake of capsaicin in individuals in Europe is much lower than that of individuals in Asian and North American countries (1.5 mg vs. 25–200 mg, respectively). Therefore, if the potential anti-cancer and carcinogenic properties of capsaicin follow a nonlinear dose response, individuals in Europe were more likely to obtain a protective effect, whereas the opposite effect would be observed in individuals in Asian and North American countries.