Spicy food boasts antigastrointestinal cancer potential

Frequent consumption of spicy food appears to protect against the risk of gastrointestinal (GI) cancers, especially oesophageal cancer, and this association is pronounced among individuals who do not smoke and drink regularly, according to a study.

“Similar, though somewhat weaker, inverse associations were also found for stomach and colorectal cancers,” the investigators said.

In a large prospective Chinese cohort of more than 510,101 adults (mean age, 52.0 years; 59 percent female)—among whom 30.1 percent reported consuming spicy food 6–7 days/week in the past month—2,350 oesophageal, 3,350 stomach, and 3,061 colorectal incident cancer cases occurred over a median of 10.1 years of follow-up.

Multivariable Cox regression analysis showed an inverse relationship between spicy food intake and oesophageal cancer risk. With non- or rare consumption as reference, monthly consumption reduced the risk by 12 percent, 1–2 days/week by 24 percent, 3–5 days/week by 16 percent, and 6–7 days/week by 19 percent (p<0.002 for trend). [Int J Epidemiol 2021;doi:10.1093/ije/dyaa275]

The association persisted despite exclusion of the first 3 years of follow-up, according to the investigators. “However, [the chemoprotective effect of spicy food intake] appeared stronger in participants who did not smoke or drink alcohol regularly (p_trend<0.0001).”

For stomach cancer, the respective HRs associated with intake frequencies of monthly, 1–2 days/week, 3–5 days/week, and 6–7 days/week were 0.97, 0.95, 0.92, and 0.89 (p=0.04 for trend), with the association disappearing after excluding the first 3 years of follow-up.

For colorectal cancer, the corresponding HRs were 1.00, 0.95, 0.87, and 0.90 (p_trend=0.04). The association appeared to be restricted to rectal rather than colon cancer.

In the cohort, spicy food intake referred to the directly consuming fresh chili peppers; adding fresh/dried chili peppers, chili oil/sauce/paste, curry, or other ‘hot’ spices when cooking; or spicing up food with the use of chili oil/sauce/paste when eating. The types and strength of spice used showed little additional effects on the observed associations.

“Previous reports on associations of spicy food consumption with GI cancers were all small case–control studies and, in contrast to our findings, they tended to show null or positive associations… To date, only two case–control studies on oesophageal cancer—one in Australia (844 cases) and another in India (236 cases)—had detailed quantitative assessment of spicy food intake,” the investigators noted.

Whereas the former reported no association with the frequency of spicy food consumption, the latter study showed a significant positive dose–response relationship with the amount of red chili powder intake. However, neither examined this association among never-regular smokers and/or never-regular drinkers to minimize residual confounding. [Cancer Causes Control 2010;21:1475-1484; Nutr Cancer 1987;10:103-113]

The anticancer potential of spicy food is attributed to capsaicin, the main bioactive constituent of spicy food. It is said to ward GI cancer by altering specific risk factors, such as inhibiting the growth of Helicobacter pylori and reducing body fat. [FEMS Microbiol Lett 2006;146:223-227; Biosci Rep 2017;37:BSR20170286; Adv Food Nutr Res 2015;76:1-28]

“Overall, it is possible that any carcinogenicity or anticarcinogenicity of capsaicin is dependent on dose, and there may be a threshold beyond which the harms start to outweigh the benefits (or vice versa), but further epidemiological studies with quantitative assessment are needed to clarify this,” according to the investigators.