🟠 Moderate Evidence
Your esophagus can sustain thermal damage from hot beverages at temperatures that would burn your mouth, yet you may feel no pain. This paradox explains why the International Agency for Research on Cancer (IARC) classified drinking beverages above 65°C as a probable human carcinogen in 2016. The damage occurs silently—your esophagus lacks the dense pain receptors of your mouth and relies instead on visceral nerve endings tuned to stretch rather than temperature.
Key takeaways
- Tea drank at 60°C or hotter carries 41% higher risk of esophageal cancer than cooler beverages, according to prospective data from 50,045 Iranian adults
- The esophagus sustains thermal injury without triggering pain because it lacks sensitive temperature-detection nerve endings
- Repeated thermal injury triggers chronic inflammation, accelerating cell turnover and mutation accumulation over years
- Drinking tea within 2 minutes of pouring increases esophageal squamous cell carcinoma risk by 51% compared to waiting 6+ minutes
Study at a Glance
| Source | International Journal of Cancer |
| Study type | Prospective cohort study |
| Sample size | N = 50,045 adults |
| Population | Adults in northeastern Iran |
| Follow-up | Median 10 years (317 esophageal cancer cases) |
| Country | Iran |
Tea Temperature and Esophageal Cancer Risk
Relative risk increase by drinking habit and temperature, Golestan Cohort Study (n=50,045)
Source: Islami et al., International Journal of Cancer, 2019 | Georgian Medical Journal News
The Silent Injury: Why Your Mouth Burns but Your Esophagus Doesn’t Signal Alarm
The reason you can swallow scalding tea without immediate discomfort relates to the anatomy of pain perception. Your mouth contains dense thermal pain receptors that fire rapidly when exposed to high temperatures. Your esophagus, by contrast, has visceral nerve endings optimized to detect stretch and distension rather than temperature change. This mismatch creates a dangerous vulnerability: tissue damage accumulates without the protective warning signal that keeps you from drinking something dangerously hot from a cup.
The esophageal lining—the squamous epithelium—sustains the same thermal injury from 65°C tea as your mouth would. But because pain feedback is absent, you repeat the injury meal after meal, day after day. Over time, this pattern of repeated heat damage triggers a cascade that leads toward cancer.
Chronic Inflammation Accelerates Mutation Accumulation
The mechanism linking thermal injury to esophageal squamous cell carcinoma is well established. According to the IARC review published in 2016, repeated thermal injury triggers chronic inflammation of the esophageal lining. This inflammatory state forces the tissue into a cycle of accelerated cell turnover—the epithelium sheds damaged cells and replaces them more rapidly than normal. Each cell division is an opportunity for DNA replication errors and mutations to accumulate.
Over years and decades, this elevated mutation rate in a chronically inflamed, rapidly replicating tissue creates conditions favourable for transformation to esophageal squamous cell carcinoma. The dose–response relationship is clear: hotter temperatures, longer exposure, larger volumes, and faster consumption all amplify the risk.
Prospective Evidence from 50,000 Adults in Iran
The strongest epidemiological evidence comes from the Golestan Cohort Study, led by Fatemeh Islami and colleagues and published in the International Journal of Cancer in 2019. Researchers prospectively followed 50,045 adults in northeastern Iran—a region with historically high rates of esophageal cancer—for a median of 10 years. During follow-up, 317 new cases of esophageal squamous cell carcinoma were recorded.
Critically, tea drinking temperature was measured objectively at baseline using a thermometer, not by self-report. This objective measurement avoided the recall bias that plagues many dietary studies. The findings were striking: adults who drank tea at 60°C or higher had a 41% higher risk of esophageal squamous cell carcinoma compared to those drinking below 60°C. Those who drank tea within 2 minutes of pouring—when it would still be very hot—had a 51% higher risk than those who waited 6 minutes or more. People consuming 700 mL or more daily at 60°C or above showed approximately 90% higher risk.
Perhaps most striking: participants who self-reported preferring “very hot” tea (versus cold or lukewarm) had a 141% higher risk—roughly 2.4 times the risk of those with lower temperature preferences. This reflects both habituation (people who regularly drink hot beverages may be more tolerant of heat) and cumulative exposure over time.
People who drank tea at 60°C or higher had a 41% higher risk of esophageal squamous cell carcinoma than those who drank below 60°C; those consuming high volumes (≥700 mL/day) at high temperatures showed approximately 90% higher risk.
— Fatemeh Islami and colleagues, International Journal of Cancer (2019)
Temperature Thresholds and Cancer Classification
The IARC classified drinking “very hot” beverages—those above 65°C—as a Group 2A carcinogen in 2016. This classification means the evidence suggests a probable causal link to human cancer, though not absolute certainty. The 60°C threshold observed in the Golestan study aligns closely with this determination: sustained exposure to temperatures in this range drives measurable increases in esophageal cancer risk.
For context on carcinogen classifications, IARC Group 2A includes substances such as processed meat consumption and shift-work exposure. The classification applies to the thermal exposure itself—not to the beverage type. Hot water carries the same risk as hot tea or hot coffee if consumed at the same temperature.
What this means
Frequently asked questions
Can I still drink hot tea safely?
Yes. Allow tea to cool to 50°C or below before drinking—typically 6 minutes or more after pouring. At this temperature, thermal injury risk is eliminated. The IARC and WHO guidance refers specifically to “very hot” beverages above 65°C consumed habitually.
Why don’t I feel pain when I swallow hot tea?
The esophagus has visceral nerve endings optimized for stretch and distension rather than temperature detection. In contrast, your mouth and throat have dense thermal pain receptors. This anatomical difference means esophageal tissue can be thermally damaged without pain feedback to warn you. The injury occurs silently.
Is the risk from hot beverages the same for everyone?
Risk varies by baseline susceptibility. Regular consumption of very hot beverages (≥700 mL daily at ≥60°C) shows the highest risk (~90% increase). Occasional hot beverage consumption carries lower absolute risk. Individuals with alcohol use disorder or tobacco smoking history have higher baseline esophageal cancer risk and should be particularly cautious about additional thermal injury.
The evidence from the Golestan Cohort Study and the IARC classification together provide clear guidance: thermal injury is a modifiable risk factor for esophageal cancer. Unlike genetic predisposition or occupational exposures, beverage temperature is entirely within individual control. A simple behavioural change—waiting a few minutes for tea to cool—removes the physiological mechanism driving increased cancer risk.
For more on esophageal health and cancer prevention, see our Clinical Updates section and explore evidence-based patient guidance on gastrointestinal health.
Source: Islami et al., International Journal of Cancer, 2019 | IARC Monographs on the Identification of Carcinogenic Hazards to Humans, 2016
Was this article helpful?
Disclaimer. This article is health journalism intended for general information and education. It is not medical advice and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your individual circumstances. Full disclaimer →
Related Coverage
Editorial standards. This article was produced under the GMJ News editorial process, with oversight by the GMJ Editorial Board. Our editorial process. Spotted an error? Contact the editorial team.
