A large prospective study conducted in China has reported that habitual tea consumption is associated with a modestly lower risk of vascular disease overall, but drinking tea at very high temperatures was linked to an increased risk compared with not drinking tea regularly.
Key findings from a nine-year follow-up
The research, published on 21 October in the Journal of Internal Medicine, followed adults aged between 30 and 79 for an average of about nine years. More than 485,000 participants were included and researchers recorded in excess of 14,800 cases of vascular disease, encompassing heart attacks, strokes and peripheral artery disease.
Study authors reported that people who drank tea at least three days per week had approximately a 11% lower risk of vascular disease compared with those who drank tea less frequently. By contrast, participants who described the temperature of their tea as "burning hot" experienced a higher risk — around 16% greater — than people who did not drink tea regularly.
| Metric | Value |
|---|---|
| Participants | ~485,000 |
| Age range | 30–79 |
| Average follow-up | ~9 years |
| Vascular events recorded | >14,800 |
Types of tea and strength
Researchers also examined tea type and strength. Moderate-strength tea consumption was associated with lower vascular risk compared with non-regular tea drinkers. When comparing varieties, black tea was linked with a lower risk across more types of vascular disease than green tea, according to the study.
Interpretation and limitations
The investigators emphasised that the study demonstrates associations rather than causation. Behavioural and lifestyle differences that were not fully accounted for could influence the observed relationships. Importantly, tea-drinking information was obtained from participants' own reports, which can introduce measurement error.
"The findings show an association, not proof that drinking tea at a particular temperature causes or prevents disease," the report noted.
Temperature-related harm may plausibly operate through thermal injury to the oesophagus or other mechanisms, but the paper does not establish the temperature itself as the direct cause of increased vascular risk. The authors acknowledged that other unmeasured factors correlated with drinking very hot beverages could contribute to the association.
- Association, not causation: observational design cannot prove a temperature effect.
- Self-reporting: tea habits were participant-reported and may be imprecise.
- Residual confounding: other lifestyle differences could explain some or all of the associations.
What this means for the public
The results suggest that moderate habitual tea drinking may be associated with some vascular benefit, while very hot tea could be linked to harm. Given the study's limitations, it would be premature to issue firm public health guidance based solely on these findings. Clinicians and public health agencies typically rely on a body of evidence — including randomised trials and mechanistic research — to shape recommendations.
These results add to a larger literature on dietary patterns and cardiovascular risk. Tea contains polyphenols such as flavonoids that have been investigated for antioxidant and anti-inflammatory effects, but this study did not determine whether those compounds explain the associations.
Further research — ideally using objective measures of beverage temperature and designs that can better reduce confounding — would be needed to clarify whether temperature itself contributes to vascular risk and to quantify any causal effects.
For now, the study highlights a potentially modifiable behaviour worth examining in future work and reminds readers that observational studies can indicate possible links but cannot confirm cause and effect.
