People who drink tea regularly appear less likely to develop heart and blood vessel disease than people who do not, according to a study published in the Journal of Internal Medicine.
Researchers led by Dr Zichen Ye of Peking Union Medical College followed 485,934 adults in China for a median of about nine years. During that time, 14,863 participants developed cardiovascular disease, cerebrovascular disease including stroke, pulmonary heart disease or peripheral artery disease.
Habitual tea drinkers had an 11% lower risk of those conditions than people who did not drink tea regularly.
How much, and which tea
The link peaked among weekly drinkers who had about six to eight cups a day. Black tea showed more consistent associations with lower risk than green tea. Tea of moderate strength was tied to the lowest risk, while tea described as burning hot was associated with a higher risk.
The lowest risk in the study appeared among people who drank tea, did not smoke and were physically active.
What the finding does not show
The study is observational. It can show an association but cannot establish that tea itself protects the heart. People who drink tea may differ from those who do not in diet, income, lifestyle or other ways that statistical models struggle to capture.
Dr Charalampos Rallis of Queen Mary University of London, who was not involved in the work, said the study adds to existing evidence but noted that the model is not fully adjusted for diet and income. He said the six to eight cups figure should not be read as a recommended intake, and that the findings on black tea and burning hot tea should be treated as exploratory because the authors tested many comparisons.
Dr Dell Stanford, a senior dietitian at the British Heart Foundation, made a similar point, saying the result adds to evidence linking tea with better cardiovascular health but does not prove that a daily cup protects the heart.
Why the population matters
The findings come from a Chinese population, where tea habits and the types of tea consumed differ from those in Europe or North America. The authors said the results need replication in other groups before any advice changes. Vascular disease remains the leading cause of death worldwide, and diet studies of this size are rare.