🟠 Moderate Evidence
The temperature at which you drink tea, coffee, or maté—not the beverages themselves—carries a measurable cancer risk. In 2016, the International Agency for Research on Cancer (IARC), a WHO agency, classified drinking very hot beverages above 65°C as “probably carcinogenic to humans,” placing them in the same risk category as indoor wood smoke exposure. Since then, multiple cohort studies and data from nearly half a million participants have confirmed the association, particularly for esophageal cancer.
Key takeaways
- Beverages consumed above 65°C are classified as “probably carcinogenic” by IARC—the risk is thermal injury, not the drink itself
- Cohort studies from South America, the Middle East, Africa, and Asia show elevated esophageal cancer risk, confirmed in Western populations via UK Biobank data
- Consuming eight or more very hot drinks daily increased esophageal cancer risk nearly six-fold; even moderate consistent exposure doubled risk in some individuals
- Simple cooling strategies—allowing drinks to cool to ~58°C, stirring, or adding milk—can reduce risk without sacrificing flavor
Classification at a Glance
| Classifying agency | International Agency for Research on Cancer (IARC) |
| Classification year | 2016 |
| Risk category | Group 2A: Probably carcinogenic to humans |
| Primary cancer type | Esophageal squamous cell carcinoma |
| Temperature threshold | ≥65°C |
Esophageal Cancer Risk by Hot Beverage Consumption Frequency
Relative risk estimates from UK Biobank cohort (n≈500,000), adjusted for age, sex, and smoking
Source: UK Biobank Esophageal Cancer Cohort, 2024 | GMJ News
Why Temperature, Not the Beverage, Is the Problem
The distinction is critical: coffee, tea, and maté carry no inherent carcinogenic properties. The hazard is thermal injury to the esophageal epithelium. When beverages exceed 65°C, they cause direct thermal damage to the delicate lining of the esophagus, triggering a cycle of chronic inflammation, impaired barrier repair, and—over years—cellular changes that can progress to cancer.
Animal studies published in peer-reviewed journals have demonstrated this mechanism directly. Water at 70°C accelerates precancerous growths in animal esophagi, and the risk compounds with repeated exposure. Critically, the damage depends not only on absolute temperature but also on sip volume and drinking frequency: larger sips deliver higher intraluminal temperatures and cause greater tissue injury.
This is why the IARC classification focuses on the thermal exposure itself, not the chemical composition of the drink.
Evidence from Multiple Continents Confirms the Risk
The evidence base for this classification is substantial. Cohort studies from regions where very hot beverages are culturally normative—South America (where maté is consumed at ~70°C), the Middle East, Africa, and Asia—have consistently documented elevated esophageal cancer risk. Researchers analyzing data from multiple maté-drinking populations found statistically significant associations even after adjusting for smoking and alcohol use, suggesting temperature is an independent risk factor.
More recent evidence extends this finding to Western populations. Data from nearly half a million participants in the UK Biobank, published in 2024, confirmed the thermal injury mechanism in a high-income, predominantly tea-and-coffee-drinking population. This finding is significant because it demonstrates that the risk is not limited to specific beverages or populations—it applies wherever very hot drinks are consumed regularly.
Consuming eight or more very hot drinks per day increased esophageal cancer risk nearly six-fold; even moderate but consistent exposure doubled risk in some individuals.
— UK Biobank Esophageal Cancer Cohort analysis, 2024
Simple, Practical Cooling Strategies
The good news is that risk reduction is straightforward and requires no sacrifice of flavor or ritual. Research suggests an optimal consumption temperature of approximately 58°C—warm enough to preserve taste and pleasure but below the threshold of esophageal thermal injury. Achieving this is simple:
- Allow drinks to cool for several minutes before consuming. A 5–10 minute wait reduces temperature substantially without requiring refrigeration.
- Stir or blow on hot beverages to accelerate cooling, especially in the cup’s center where hottest liquid pools.
- Remove lids from takeaway cups, which trap heat and slow cooling. Exposed beverages cool faster.
- Add cold water or milk, which immediately reduces temperature while preserving flavor through dilution rather than elimination.
These strategies are particularly important for individuals who consume multiple hot beverages daily, shift workers with irregular meal schedules, or those in occupations (such as healthcare) where quick consumption is common. For such populations, establishing a brief cooling habit can meaningfully reduce lifetime esophageal cancer exposure.
The clinical message is clear: the beverage itself—whether coffee, tea, or any other hot drink—poses no unique cancer risk. Temperature alone determines the hazard. This is why public health messaging should emphasize thermal exposure rather than avoiding beloved beverages.
Implications for Clinicians and Public Health
For primary care physicians and gastroenterologists, the evidence supports brief counseling on beverage temperature as part of esophageal cancer prevention, particularly in high-risk populations (those with family history of esophageal cancer, smokers, or heavy alcohol users, in whom thermal injury compounds other risk factors). For public health authorities, the IARC classification argues for simple, low-cost public awareness campaigns highlighting the thermal mechanism rather than demonizing specific drinks.
In regions where very hot beverages are deeply embedded in culture—maté in Argentina and Paraguay, tea in Iran and East Africa, coffee in Ethiopia—tailored messaging that acknowledges cultural practices while promoting cooling strategies is more likely to achieve behavior change than blanket warnings against the drinks themselves.
What this means
If you regularly consume very hot beverages, allow them to cool to warm (rather than scalding) temperature before drinking. Simple cooling strategies—waiting a few minutes, adding milk, or using an open cup instead of a lid—reduce esophageal thermal injury without requiring you to give up tea, coffee, or other hot drinks. Risk is dose-dependent; frequent heavy drinkers face the highest risk.
Incorporate a brief question about habitual beverage temperature into esophageal cancer risk assessment, particularly in high-risk patients (smokers, heavy drinkers, those with family history). The evidence supports counseling on cooling rather than avoidance. For patients with chronic reflux disease or Barrett’s esophagus, thermal injury adds an additional hazard and warrants explicit discussion.
Public health campaigns targeting esophageal cancer prevention should emphasize thermal exposure and practical cooling strategies rather than discouraging consumption of tea, coffee, or maté—beverages with documented health benefits when consumed at safe temperatures. In high-consumption regions, culturally sensitive messaging that respects traditional beverage practices while promoting simple cooling methods is evidence-aligned and more likely to achieve engagement.
Frequently asked questions
Is the carcinogenic risk from hot beverages the same as from smoking?
No. The IARC Group 2A classification means “probably carcinogenic”—a lower certainty than Group 1 (carcinogenic). The absolute risk from very hot beverages is lower than from tobacco or alcohol. However, the risk is real and dose-dependent: frequent consumers of very hot drinks face measurably elevated esophageal cancer risk, particularly when consumed with smoking or heavy alcohol use, which compound thermal injury.
Does tea or coffee contain any carcinogenic chemicals?
No. IARC classifications for both tea and coffee (as beverages consumed at normal temperatures) show no carcinogenic hazard from the drinks themselves. Coffee is not classified as carcinogenic; tea is not classified as carcinogenic. The 2016 classification of “very hot beverages” as probably carcinogenic refers exclusively to thermal injury, not chemical composition.
What temperature is safe for hot beverages?
Research suggests approximately 58°C (~136°F) is a practical safe threshold—warm enough to preserve flavor and drinking enjoyment but below the 65°C threshold at which thermal injury begins. Most household thermometers or smartphone apps can measure cup temperature. If a beverage is too hot to hold a spoon comfortably for 5 seconds, it is likely above 58°C and should cool further.
As global consumption of hot beverages—tea, coffee, maté, and others—continues to rise, the evidence linking temperature to esophageal cancer has become increasingly robust. The good news is that prevention requires no sacrifice of these beloved drinks. Simple cooling practices, informed by evidence and supported by clinical counseling, can substantially reduce risk while preserving the cultural and social meaning of hot beverage consumption worldwide.
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