Study: High chili pepper consumption may increase risk of certain cancers

Scientists have long debated whether eating chili peppers can affect cancer risk. While laboratory experiments have shown anti-inflammatory and even anticancer properties, some human studies have linked very high consumption to a greater risk of certain digestive tract cancers.

A recent review published in Frontiers in Nutrition pooled data from 14 observational studies involving more than 11,000 participants, including over 5,000 with gastrointestinal cancers. Compared to those who consumed the least chili peppers, those with the highest intake were about 64% more likely to develop any gastrointestinal cancer. The strongest link was with esophageal cancer: the highest consumption group had nearly three times the risk.

For stomach and colorectal cancers, researchers found no statistically significant increase in risk. Stomach cancer showed a trend toward higher risk (about 77% higher), but it was not statistically significant.

Regional differences

Results varied by region. Studies from Asia, Africa, and North America generally found higher cancer risks among heavy chili consumers. In contrast, studies from Europe and South America found no increased risk or even lower risks. Researchers attribute these differences to factors such as pepper varieties, cooking methods, genetics, smoking, alcohol use, and other dietary habits.

Why the esophagus may be vulnerable

Scientists hypothesize that capsaicin, the compound that makes peppers hot, activates TRPV1 receptors, causing a burning sensation. Repeated exposure to very spicy foods may lead to chronic irritation of the esophageal lining. However, these ideas remain unproven.

Caution warranted

Despite the concerning findings, researchers urge caution. All included studies were observational, meaning they can identify associations but not causation. Other factors like smoking, alcohol, socioeconomic status, infections, or overall diet could explain the results.

One major unanswered question is the role of dose. It is unclear whether moderate chili consumption carries the same risk as very high intake or whether a threshold exists. Long-term studies are needed to determine whether chili peppers directly contribute to cancer development or whether the observed associations are driven by other lifestyle and environmental factors.