Your morning cup may be doing your heart a favour, but only if you let it cool down first. A large new study suggests that regular tea drinkers have a lower risk of vascular disease than non-drinkers, while people who like their tea 'burning hot' lose that advantage and may even come out worse.
The findings, published last week in the Journal of Internal Medicine, are the latest twist in the long-running story of tea and heart health. They also come with some important fine print.
The study followed more than 4,85,000 adults in China, aged 30 to 79, for about nine years. Researchers asked how often they drank tea, what kind, how strong, and how hot, then tracked more than 14,800 cases of vascular disease, including heart attacks, strokes and peripheral artery disease.
Regular tea drinkers had roughly an 11 percent lower relative risk of vascular disease than people who didn't drink tea regularly. Temperature changed the picture:
Burning hot: about 16 percent higher risk than non-drinkers.
Hot but not scalding, or room temperature: significantly lower risk than non-drinkers.
Two other details stood out. Black tea showed more consistent links to lower risk across vascular conditions than green tea, though green tea also looked beneficial. And moderate-strength tea was the kind linked to lower risk. Among weekly drinkers, the lowest estimated risk came at around six to eight cups a day.
The study doesn't explain how very hot tea could harm blood vessels, so any mechanism is speculation for now. Earlier research does link tea to modest improvements in blood pressure, cholesterol and other cardiovascular markers, which fits with the overall benefit seen in drinkers.
There is a separate, better-established reason to let your cup cool. The World Health Organization's cancer agency has classified very hot beverages, roughly above 65°C, as probably carcinogenic for esophageal cancer, likely because repeated heat injury irritates the throat. That is a different disease from the one in this study, but it points the same way: scalding is best avoided.
Dell Stanford, a senior dietitian at the British Heart Foundation, noted that tea intake was recorded only once, cup sizes weren't standardised, and other diet and lifestyle differences could explain the results. The lowest risk appeared in people who drank tea, did not smoke and were physically active, which suggests tea works best as part of a healthy routine, not as a substitute for one.
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