Tea lowers heart disease risk; hot tea may harm

A large study followed 485,934 adults in China for a median of 9.05 years and recorded 14,863 cases of vascular disease. These included heart disease, stroke, lung-related heart problems and peripheral artery disease. People who drank tea regularly had an 11% lower risk of these combined outcomes than those who did not.

The benefit varied with how much tea people drank. Among those who drank tea at least weekly, the lowest estimated risk appeared at roughly six to eight cups a day. Because the study was observational, it could not prove that tea directly prevented disease, only that the pattern was linked to lower risk.

Black tea shows more benefit

Black tea showed more consistent benefit. Its link to lower risk was steadier than green tea's, even though both come from the same plant. Moderate-strength tea was linked to the lowest risk, suggesting stronger tea was not necessarily better. The study did not establish whether polyphenols, plant compounds in tea, explain these differences.

Temperature mattered too. Participants who drank tea described as "burning hot" had a higher risk of vascular disease. The researchers did not identify a specific temperature threshold or a biological mechanism, so the finding raises questions rather than proving that very hot tea causes harm.

The study also looked at tea alongside other habits. People who drank tea regularly, did not smoke and were highly active had the lowest vascular disease risk. The authors said this combination was linked to the lowest risk among the groups studied.