A Journal of Internal Medicine study of 485,934 adults in China found regular tea drinkers had an 11% lower risk of vascular disease, but burning-hot tea was linked to higher risk. The research is observational and cannot prove cause.
Researchers have reported that people who drink tea regularly appear to have a lower risk of vascular disease. The study, published in the Journal of Internal Medicine and summarised in a Wiley press release carried by ScienceDaily, followed 485,934 adults in China for a median of 9.05 years. During that time 14,863 cases of vascular disease were recorded, including cardiovascular disease, cerebrovascular disease, pulmonary heart disease and peripheral artery disease. Regular tea consumption was associated with an 11% lower risk of these outcomes combined.
The details of how people drank tea seemed to matter. Among those who drank tea at least weekly, the lowest estimated risk occurred at roughly six to eight cups a day, and black tea showed more consistent associations with lower risk than green tea. Moderate-strength tea was linked to the lowest risk, suggesting stronger brews were not necessarily better. Drinking tea described as burning hot, however, was associated with an increased risk, although the study did not identify a specific harmful temperature or explain the biological mechanism behind the result.
The authors and the press summary stress important limits. Because the research is observational, it shows associations rather than proving that tea itself protects blood vessels, and the findings should not be read as advice to drink six to eight cups a day. Participants who drank tea, did not currently smoke and were highly physically active had the lowest vascular risk, which points to overall lifestyle rather than a single drink. The result comes from one population in China and has been reported here through one publisher's summary, so further research is needed to confirm whether tea itself influences disease risk.
