Large Study Associates Regular Tea Drinking With Lower Vascular Disease Risk

A study published in October in the Journal of Internal Medicine reported that people who drink tea regularly had an 11% lower relative risk of vascular disease compared with people who did not drink tea often.

The findings were based on an analysis of 485,934 participants in the China Kadoorie Biobank, a large prospective cohort study in China. During a mean follow-up of 9.05 years, researchers documented 14,863 cases of incident vascular disease. The study defined habitual tea drinking as consuming tea on at least 3 days per week.

The research adds to a growing body of evidence linking tea consumption to cardiovascular health, though experts cautioned that the observational design cannot establish cause and effect. Vascular disease refers to conditions affecting the blood vessels, including cardiovascular disease, stroke, pulmonary heart disease, and peripheral artery disease.

The study’s main outcome was the first occurrence of any of these conditions during the follow-up period. The researchers reported that the association remained after adjusting for factors such as age, sex, education, smoking, alcohol intake, physical activity, and body mass index.

Study Design and Main Findings

The study was observational and compared regular tea drinkers with people who did not regularly drink tea. It followed participants over time to see who developed vascular disease. Because participants were not randomly assigned to drink tea or not, the study cannot prove that tea directly prevents vascular disease, the report stated. Researchers noted that people who drink tea regularly may differ from non-drinkers in other health-related behaviors.

Among weekly tea drinkers, the lowest risk was observed in those who drank about 6 to 8 cups per day, according to the study. Moderate-strength tea was associated with lower observed risk than weak or strong tea.

The study also examined tea type and found that black tea was associated with the lowest vascular disease risk, with a relative reduction of at least 35%, researchers reported. Green tea was also associated with a lower risk, though not as low as black tea in the study.

The study’s findings are consistent with previous research. A meta-analysis of green tea consumption and cardiovascular disease risk found that drinking five or more cups of green tea a day was negatively correlated with cardiovascular and cerebrovascular disease and mortality from various causes [1]. Another review noted that consumption of green or black tea has been inversely associated with the development and progression of cardiovascular diseases [2].

Tea Type and Temperature Results

The study reported differences by tea type and preparation temperature. Black tea was associated with the lowest vascular disease risk, with a relative reduction of at least 35%, researchers reported. Green tea was also associated with a lower risk of vascular disease, though not as low as black tea in the study. The researchers noted that black tea is the most commonly consumed type in the study population.

Participants who reported drinking tea at a “burning hot” temperature had a 16% higher risk compared with people who did not drink tea. The researchers did not obtain specific tea temperatures and relied on participants’ subjective perceptions of temperature. Charalampos Rallis, PhD, said in a Science Media Centre debrief that findings on black tea and “burning hot” tea should be treated as exploratory.

The temperature finding aligns with broader research on beverage temperature and esophageal health. The study’s authors cautioned that the observational nature of the data limits conclusions about causality. The results on tea type and temperature were secondary analyses and require confirmation in other populations.

Experts Caution on Interpretation

Christopher Yi, MD, a vascular surgeon not involved in the study, told Medical News Today he was “not particularly surprised” by the findings and cited antioxidants and polyphenols as possible factors. Yi said an 11% reduction in relative risk is clinically meaningful but added that the study demonstrates an association rather than proving that tea directly prevents vascular disease.

Dell Stanford, a senior dietitian with the British Heart Foundation, said in a Science Media Centre debrief that 6 to 8 cups a day should not be treated as a recommended amount. Stanford said tea intake was measured once and cup size was not standardized, and the study cannot prove that drinking more tea caused the lower risk.

The study’s limitations include the use of self-reported tea consumption, which may be subject to recall bias. The researchers also noted that tea drinking habits may change over time. Despite these limitations, the study’s large sample size and long follow-up period provide valuable data on the relationship between tea and vascular disease.

Tea in Context of Other Lifestyle Factors

The study found that regularly drinking tea alongside avoiding smoking and maintaining high physical activity was associated with the largest reduction in vascular disease risk. Participants who combined these healthy behaviors had a lower risk than those who adopted only one or none of them. The researchers emphasized that tea drinking should be considered as part of an overall healthy lifestyle.

Yi told Medical News Today that cardiovascular health depends on multiple lifestyle factors rather than one particular habit. Yi said tea consumption may provide additional benefits but should complement established preventive measures rather than replace them. He said he generally recommends unsweetened tea and advises avoiding excessive sugar or high-caffeine tea products.

The findings are consistent with public health guidance that emphasizes a holistic approach to cardiovascular prevention. The American Heart Association recommends a healthy diet, regular physical activity, avoiding tobacco, and maintaining a healthy weight to reduce the risk of cardiovascular disease. Tea can be part of a heart-healthy diet, particularly when consumed without added sugars.

Conclusion

The study reports an association between regular tea drinking and lower relative risk of vascular disease, not a proven causal effect. The researchers and independent experts emphasized that the observational design cannot rule out confounding factors. People who drink tea regularly may have other characteristics that protect their heart health.

Yi said additional research is needed to determine whether tea consumption itself directly reduces cardiovascular events. Randomized controlled trials would provide stronger evidence, but such trials are difficult to conduct over long periods.

The current evidence suggests that tea may be a useful addition to a heart-healthy lifestyle. Experts quoted in the report advised that tea can be part of a heart-healthy lifestyle but is not a substitute for managing established cardiovascular risk factors.

Regular tea drinking should be combined with other preventive measures such as avoiding smoking, maintaining physical activity, and managing blood pressure and cholesterol. The study’s findings provide reassurance for tea drinkers but do not justify drinking excessive amounts of tea or relying on tea alone for cardiovascular protection.

References

1. Tea Polyphenols Oxidative Stress and Health Effects Volume 1 2 1023 Pages by Baolu Zhao
2. The role of tea and tea flavonoids in cardiovascular health by 3B2 Total Publishing System 7.51n/W. Mol. Nutr. Food Res. 2006, 50, 218–228

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