Does Eating Chili Peppers Increase the Risk of Esophageal Cancer? The Study That Shook Spice Lovers

Chili peppers add a sharp stimulus and aroma to dishes. Whether it's mapo tofu, curry, kimchi, dan dan noodles, tacos, or tom yum goong, chili peppers are indispensable in culinary cultures worldwide.

In Japan, restaurants offering extremely spicy dishes and videos challenging the limits of spiciness have gained popularity. While some enjoy chili peppers as a common spice, there are enthusiasts who pour large amounts of hot sauce or eat extremely spicy varieties whole.

For such spice lovers, a concerning study suggests that people who consume a lot of chili peppers may have a higher risk of esophageal cancer.

Looking at the numbers alone, the high consumption group might be interpreted as having "about three times" the risk of esophageal cancer. On social media, surprise and anxiety spread, with reactions like "Another favorite food is said to be unhealthy" and "Please don't take away the joy of eating spicy food."

However, interpreting this number as "eating chili peppers causes esophageal cancer" is not accurate.

The study indicates a statistical correlation between chili pepper consumption and cancer occurrence. It does not prove that chili peppers are the direct cause or that people who consume typical amounts are at the same risk.

To understand this topic, it's necessary to examine the research methods and limitations behind the sensational headlines.

14 Studies, Data from 11,310 People Integrated

The basis for the attention was a meta-analysis published in the medical journal "Frontiers in Nutrition" in 2022.

A meta-analysis is a method that collects and integrates results from multiple previously published studies based on certain criteria, allowing for a broader understanding by targeting more participants than individual studies.

The research team searched for studies examining the relationship between chili pepper consumption and esophageal cancer, gastric cancer, and colorectal cancer. Ultimately, 14 studies with a total of 11,310 participants were analyzed, of which 5,009 were diagnosed with gastrointestinal cancer.

Comparing the group with the highest chili pepper consumption to the group with the lowest, the odds ratio for overall gastrointestinal cancer was 1.64 in the high consumption group. Simply put, the group that consumed more chili peppers had a higher rate of gastrointestinal cancer.

The strongest correlation was found with esophageal cancer, with an odds ratio of 2.71. In the high consumption group, the odds of esophageal cancer were about 2.7 times higher compared to the low consumption group.

On the other hand, no statistically significant correlation was found for gastric cancer and colorectal cancer. Although there was an increasing trend for gastric cancer, the possibility of a chance difference could not be fully ruled out.

In other words, the results do not suggest that "chili peppers increase all gastrointestinal cancers equally." The most notable finding in this analysis was the correlation with esophageal cancer.

"2.71 Times" Does Not Simply Mean the Probability of Occurrence is Tripled

When it comes to health information, it's important to be cautious about expressions like "risk is about three times higher."

The figure of 2.71 shown in the study is an odds ratio and does not mean that an individual's probability of developing esophageal cancer in the future uniformly increases by 2.71 times. The actual absolute risk varies depending on the original incidence rate, the age of the subjects, smoking, drinking, region, diet, and other factors.

For example, in diseases with very low incidence, even if the relative figure is large, the absolute increase for an individual may be small.

Furthermore, the definition of "high consumption" in the study is not standardized.

In one study, eating daily was considered high consumption, while in another, responses to questions like "frequently eating" or "preferring very spicy dishes" were the criteria. Some studies asked about annual intake, while others examined how many times a week chili peppers were consumed.

The type and spiciness of chili peppers also vary. From relatively mild varieties with sweetness to those that provide intense stimulation even in small amounts, the amount of capsaicin can differ significantly even when simply referred to as chili peppers.

Therefore, specific boundaries like "exceeding a certain number of grams per day is dangerous" or "up to a certain number of times per week is safe" cannot be derived from this study.

Why Was the Correlation with the Esophagus So Strong?

Researchers are focusing on capsaicin, the component that gives chili peppers their spiciness.

Capsaicin stimulates the receptors of nerves that respond to heat and pain. When you eat chili peppers, the heat felt in your mouth, the sweating, and the runny nose are not because the food's temperature has actually increased. It's because the nerves receive stimuli similar to heat or pain.

This stimulus also reaches the esophagus.

In cases of repeated consumption of extremely spicy foods, it's hypothesized that the mucous membrane of the esophagus may continue to be stimulated in some individuals, potentially affecting the process of inflammation and tissue repair. If cells are repeatedly damaged and repaired over a long period, changes in the cells may become more likely.

However, this is not a confirmed mechanism at this stage.

Laboratory studies have reported that capsaicin might inhibit the growth of certain cancer cells or promote cell death. There are also studies showing antioxidant effects, anti-inflammatory effects, and impacts on metabolism.

On the other hand, it has been suggested that under certain conditions, capsaicin might stimulate pathways related to cell proliferation and inflammation.

Capsaicin is neither a simple "carcinogen" nor an "anti-cancer component," and its effects may vary depending on the intake amount, concentration, tissues it contacts, duration of intake, and individual constitution. This complexity adds to the difficulty of the discussion surrounding chili peppers and health.

Results Varied Greatly by Region

The meta-analysis also confirmed significant regional differences.

Studies conducted in Asia, Africa, and North America showed a positive correlation between high chili pepper consumption and gastrointestinal cancer. In contrast, studies in Europe and South America did not show an increased risk, and some even showed lower results in the high consumption group.

Why do results differ by region even though the same chili peppers are being consumed?

One possible reason is the difference in consumption amounts. Regions that add small amounts to dishes differ significantly in total capsaicin exposure from those that use large amounts of chili peppers in almost every meal.

Cooking methods may also have an impact. Fresh chili peppers, dried powder, fermented foods, and sauces dissolved in oil differ in intake methods and combinations with other ingredients.

Additionally, foods eaten with chili peppers, salt intake, consumption of meat and vegetables, habits of drinking and smoking, preference for hot food and drinks, prevalence of gastroesophageal reflux disease, genetic constitution, and access to healthcare can all influence the results.

No one lives on chili peppers alone. In epidemiological studies, it's difficult to completely isolate the impact of a single food from the entire food culture.

The significant regional differences suggest that "how chili peppers are consumed within lifestyle habits" may be more important than the chili peppers themselves.

There Was Significant Variability Among the Studies

A key point to note in this analysis is the significant variability among the integrated studies.

The indicator showing the heterogeneity of study results exceeded 90%. This means it's hard to say that each study measured the same phenomenon under the same conditions.

The countries involved, characteristics of participants, methods of asking about chili pepper consumption, types of cancer, and adjusted lifestyle factors differed across studies.

Moreover, all 14 studies were case-control studies.

In case-control studies, people diagnosed with cancer and those not diagnosed are often asked to recall their past dietary habits. Since they are recalling "how much chili pepper they used to eat" after becoming ill, their memories might not be accurate.

People diagnosed with cancer might try to find a cause and report consuming more spicy foods than they actually did. Conversely, they might underestimate their regular intake.

Furthermore, not all studies adjusted equally for smoking, drinking, gastroesophageal reflux disease, obesity, income, education, infections, etc.

Considering these conditions, while the odds ratio of 2.71 is a signal that cannot be ignored, it is not a final conclusion. Large-scale cohort studies tracking future dietary habits and studies examining risk by intake amount are needed.

"It's Safe Because We've Eaten It for Ages" or "It's Carcinogenic Because It's Spicy" Are Both Unfounded

Chili peppers have been consumed for hundreds or even thousands of years. Some people think, "Many people have eaten it for ages, so it must be safe."

On the other hand, there are intuitive opinions like, "It's painful when you eat it, so it must damage the esophagus and cause cancer."

Neither of these alone constitutes scientific evidence.

Even traditionally consumed foods can have different health impacts depending on the intake amount and cooking method. Also, feeling pain when eating is not the same phenomenon as the long-term occurrence of cancer.

The burning sensation from capsaicin is mainly a reaction of nerve receptors, and the esophagus is not physically burning every time you feel spiciness.

However, some people experience worsened heartburn or gastroesophageal reflux symptoms from strong spiciness. If stomach acid repeatedly refluxes into the esophagus over a long period, it can potentially affect the esophageal mucosa.

Thus, it's necessary to consider not only the simple structure of chili peppers directly causing cancer but also indirect pathways, such as exacerbating reflux symptoms that are repeated.

On Social Media: Anxiety, Resistance, Jokes, and Calm Analysis Intersect

When the study was introduced as news, various reactions spread on social media and online forums.

Notable were the feelings of confusion, such as "Yet another favorite food is said to be unhealthy" and "Isn't everything dangerous to eat in the end?"

Foods previously introduced as healthy are pointed out as risks in other studies. Such repeated news can lead some to distrust nutritional research itself.

From spice enthusiasts, there was resistance like "I'd rather prioritize enjoyment than give up chili peppers" and "I can't imagine life without spiciness."

Some joked, referencing a popular overseas show, "Will there be fewer participants on shows where people are interviewed while eating hot sauce?" There were also sarcastic responses like "The only safe way is to eat nothing," reflecting the typical social media atmosphere of taking serious health news with humor.

On the other hand, cautious opinions emerged from users who checked the research content.

They pointed out issues like "The criteria for high consumption differ by study," "Case-control studies alone can't prove causation," and "To what extent have the effects of reflux esophagitis, smoking, drinking, and hot beverages been excluded?"

There were also posts speculating that "It's not the chili peppers themselves, but the repeated reflux from eating spicy foods that might be affecting the correlation with esophageal cancer."

Additionally, some emphasized moderation, saying, "It's a matter of excessive consumption being problematic, so there's no need to fear small amounts."

These reactions are not a public opinion survey but merely the voices of some users who posted. Nonetheless, it shows that people receiving health news are torn between anxiety over numbers and attachment to food culture.

Don't Forget the Established Risk Factors Beyond Chili Peppers

When considering esophageal cancer, it's essential to also focus on factors that are more clearly known at this point.

Esophageal cancer mainly includes squamous cell carcinoma and adenocarcinoma, and the risk factors are not entirely the same.

For squamous cell carcinoma, the relationship with smoking and heavy drinking is known. Special caution is needed when both habits overlap.

For adenocarcinoma, gastroesophageal reflux disease, Barrett's esophagus, and obesity are important factors. Repeated reflux of stomach acid into the esophagus can cause long-term changes in the mucosa, increasing future risk.

The World Health Organization also lists avoiding tobacco, reducing alcohol consumption, maintaining a healthy weight, a balanced diet including fruits and vegetables, and exercise as preventive measures for cancer overall.

Focusing solely on one study about chili peppers and overlooking more established factors like smoking, heavy drinking, obesity, and chronic reflux symptoms would be counterproductive.

Should Spice Lovers Quit Chili Peppers?

Current research does not provide grounds to ban chili peppers for everyone.

The comparison was mainly between the group with the highest consumption and the group with the lowest, and the extent of risk for typical low to moderate consumption is unknown.

The research team also stated that due to a lack of data, they could not conduct a dose-response analysis. In other words, it's unclear whether the risk increases gradually with more consumption or changes only when a certain amount is exceeded.

Realistically, it would be more reasonable to avoid extreme consumption while monitoring the body's reactions rather than fearing chili peppers and avoiding them entirely.

There is room to reconsider habits like using so much hot sauce that the taste of the dish is unrecognizable, continuing to eat despite severe pain, or consuming it daily despite gastrointestinal symptoms.

Spiciness can be beneficial in enhancing the satisfaction of meals even with low salt content. It's important not to simply categorize chili peppers as good or bad but to consider the overall balance of the diet, intake amount, and compatibility with one's health.

If Symptoms Persist, Don't Just Blame "Spicy Foods"

The early symptoms of esophageal cancer can be difficult to distinguish from everyday discomfort.

If symptoms like food getting stuck, difficulty swallowing, pain when swallowing, persistent heartburn or acid reflux, unexplained weight loss, hoarseness, or vomiting after meals persist, it's important not to self-diagnose as merely "because of eating spicy foods."

Having these