Regular tea consumption was associated with a lower risk of cardiovascular and other vascular diseases in a large study of 485,934 adults in China. Participants were followed for a median of 9.05 years, during which researchers recorded 14,863 cases of vascular disease.
The conditions examined included cardiovascular disease, cerebrovascular disease, pulmonary heart disease and peripheral artery disease. Taken together, regular tea consumption was associated with an 11% lower risk of these outcomes compared with not drinking tea.
Among participants who drank tea at least weekly, the lowest estimated risk was associated with consuming approximately six to eight cups per day. The researchers stressed that the observational design can identify associations but cannot prove that tea itself prevented disease or determine that this amount is appropriate for everyone.
The study also found differences related to tea variety. Black tea had more consistent associations with reduced vascular disease risk than green tea. Both varieties come from Camellia sinensis, but black tea undergoes more extensive oxidation, while green tea is processed to limit it. The researchers did not establish whether these processing differences or tea compounds such as polyphenols explained the results.
Tea strength appeared to be relevant as well. Moderate-strength tea was linked to the lowest associated risk, meaning stronger tea was not necessarily connected with greater benefits.
Temperature produced the most unexpected finding. Although regular tea drinking was generally associated with lower vascular risk, consuming tea described as “burning hot” was associated with increased risk. The study did not identify a specific harmful temperature or establish the biological mechanism behind the association, so the result does not prove that extremely hot tea directly causes vascular disease.
Researchers also considered smoking and physical activity. The lowest vascular disease risk was observed among people who regularly drank tea, were not current smokers and reported high levels of physical activity. The authors said these factors were collectively associated with vascular risk, emphasizing that tea consumption should be considered within a broader lifestyle pattern.
The findings, published in the Journal of Internal Medicine, suggest that the amount, type, strength and temperature of tea may all be relevant to its relationship with vascular health. Further research is needed to determine whether tea consumption directly influences the risk of these diseases.
Sources: ScienceDaily.