Whether you prefer black tea or green, strong or mild, your daily cup may have something to do with your heart health. A new study suggests that regular tea drinkers have a lower risk of diseases affecting the heart and blood vessels, although some drinking habits appear to matter more than others.
Researchers followed nearly 486,000 adults in China for about nine years and found that regular tea drinkers had an 11% lower risk of vascular disease than those who didn't drink tea. The findings, published in the Journal of Internal Medicine, add to evidence linking tea consumption with cardiovascular health, but they don't prove that tea itself prevents disease.
During the study, nearly 15,000 participants developed conditions affecting the heart or blood vessels. Researchers looked at how those outcomes related to people's tea preferences, including the type they drank, how strong they brewed it and how hot they served it.
One finding might surprise green tea enthusiasts. Black tea showed a more consistent connection to lower vascular disease risk than green tea, which often gets more attention for its potential health benefits. Moderate-strength tea was also associated with the lowest risk.
Temperature brought another interesting twist. People who drank their tea burning hot had a higher risk of vascular disease. Researchers couldn't establish whether the temperature itself was responsible, but the finding suggests that how people enjoy their tea may deserve further attention.
The study also found that the lowest estimated risk occurred among people drinking approximately six to eight cups per day. That doesn't mean everyone should start filling the kettle more often. Cup sizes and tea-drinking habits vary, and the research doesn't establish an ideal amount to drink.
Previous studies have also linked tea consumption with better cardiovascular health. But separating the possible benefits of tea from other habits isn't easy.
For example, participants who regularly drank tea, didn't currently smoke and were physically active had the lowest risk. Other differences in lifestyle and diet could also help explain why tea drinkers appeared to have better outcomes.
The study has additional limitations. It relied on people's reported tea habits rather than assigning them to drink specific amounts or types of tea. And because the participants lived in China, where tea preparation and drinking traditions may differ from those in the United States, the findings may not apply equally to everyone.
The study was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Kadoorie Charitable Foundation in Hong Kong and the Wellcome Trust in the United Kingdom.