Common cooking ingredient could raise the risk of one deadly cancer

People who consume the highest amounts of chili peppers may face a greater risk of developing certain digestive cancers, particularly esophageal cancer, according to a large review of existing research. However, experts say the findings do not prove that spicy foods directly cause cancer and should be interpreted carefully. 

Researchers analyzed data from 14 observational studies involving more than 11,000 participants, including over 5,000 people diagnosed with gastrointestinal cancers. They found that people with the highest chili pepper intake were around 64 percent more likely to develop gastrointestinal cancers overall compared with those who consumed the least. 

The strongest association was seen for esophageal cancer. According to the analysis, people in the highest consumption group were nearly three times more likely to develop the disease than those in the lowest intake group. 

However, the findings were less clear for other digestive cancers. The researchers did not find a statistically significant increase in the risk of stomach or colorectal cancer. While stomach cancer showed a trend toward higher risk among heavy chili pepper consumers, the increase did not reach statistical significance. 

Dr. Edmundo Rodriguez-Frias, medical contributor of Full of Life, a recovery center located in Marlton, New Jersey, told Newsweek that the current evidence is not strong enough to recommend that healthy people stop eating spicy foods. 

“At this time, the research does not show sufficient evidence from a gastroenterological standpoint to support telling healthy individuals to stop consuming spicy foods. While observational studies can provide some indication of associations among various diseases and potential risk factors, they do not establish causality. This is particularly relevant given that there are many established causes of esophageal cancer which may coincide with specific dietary behaviors,” Rodriguez-Frias said.

The review’s findings come from observational studies, meaning researchers can identify possible links between chili pepper consumption and cancer risk but cannot determine whether chili peppers themselves are responsible for causing disease. 

Rodriguez-Frias explained that studying chili pepper intake can be challenging because definitions of high consumption vary and researchers often depend on participants accurately reporting their eating habits. 

“This is one of the reasons that it is difficult to design and interpret observational studies regarding high levels of chili pepper use. For example, ‘high’ use of chili peppers is very much dependent on how each individual defines this term. It can also change based on what type of pepper was used, how frequently it was consumed, etc. Furthermore, researchers who conduct such studies almost exclusively rely on self-reported food intake surveys that are susceptible to recall errors and other types of measurement errors,” Rodriguez-Frias said. 

Chili peppers contain capsaicin, the compound responsible for their spicy heat. Scientists have long debated the potential effects of capsaicin on cancer risk because previous laboratory studies have produced mixed results. Some research has suggested it may have anti-inflammatory effects, while other findings have raised questions about possible pro-inflammatory effects in certain situations. 

“From a biological standpoint, the possible mechanisms by which chronic irritation could be associated with esophageal cancer development have been explored. However, there is currently little-to-no conclusive evidence to suggest that capsaicin itself is directly responsible for causing esophageal cancer in humans. Additionally, the body of evidence generated from laboratory-based research has provided mixed findings. Specifically, capsaicin has demonstrated both anti-inflammatory and potentially pro-inflammatory properties in different contexts,” Rodriguez-Frias said. 

The review also found differences between regions. Studies conducted in Asia, Africa, and North America generally reported higher cancer risks among people with the greatest chili pepper consumption, while studies from Europe and South America found either no increased risk or lower risks. 

Researchers said these differences could be related to several factors, including variations in chili pepper intake, cooking methods, pepper varieties, genetics, smoking habits, alcohol consumption, and other dietary patterns. 

One possible explanation researchers have explored is that repeated exposure to very spicy foods could contribute to irritation of the esophageal lining in susceptible people. Capsaicin activates TRPV1 receptors, which create the burning sensation associated with spicy foods. However, these potential mechanisms remain hypotheses and have not been proven. 

Rodriguez-Frias said that for patients, the more immediate concern may be whether spicy foods worsen symptoms such as heartburn or gastroesophageal reflux disease (GERD). 

“The most pressing concern for patients will likely revolve around controlling their symptoms. Specifically, if a patient experiences consistent worsening of heartburn symptoms due to spicy foods, or if spicy foods exacerbate gastroesophageal reflux disease (GERD) symptoms, limiting these products may lead to improved overall quality of life. It is worth noting that chronic, uncontrolled acid reflux is a known risk factor for developing esophageal cancer/adenocarcinoma,” Rodriguez-Frias said. 

He emphasized that cancer prevention advice should focus on risk factors with stronger evidence rather than avoiding spicy foods alone. 

“Avoid tobacco smoking. Limit excessive alcohol use. Maintain a healthy weight. Manage chronic reflux symptoms. Seek medical attention for persistent difficulty swallowing, unexplained weight loss, or continued heartburn symptoms. These interventions have significantly more robust bodies of evidence supporting their effectiveness for preventing cancer than avoiding spicy foods,” Rodriguez-Frias said. 

For now, researchers say more long-term studies are needed to determine whether chili peppers themselves play a direct role in cancer development or whether the observed associations are influenced by other lifestyle and environmental factors. 

Reference

Contact Newsweek editors on this story: Kara Dolman and Emma Lee-Sang

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