A large study found that habitual tea drinkers had a lower risk of vascular disease, with black tea showing more consistent benefits than green tea, while consuming tea at extremely high temperatures was associated with increased risk.
By yourNEWS Media Newsroom
Regular tea consumption was associated with an approximately 11% lower risk of cardiovascular and other vascular diseases in a study involving nearly 486,000 adults, with researchers finding that the type, strength, temperature and amount of tea consumed may influence its relationship with heart health.
The study, published Oct. 21 in the Journal of Internal Medicine, analyzed health information from 485,934 participants in the China Kadoorie Biobank over an average follow-up period of 9.05 years.
During that time, researchers documented 14,863 new cases of vascular disease, including conditions affecting the heart, brain and peripheral blood vessels.
Participants who regularly consumed tea experienced an approximately 11% lower relative risk of vascular disease than those who did not habitually drink it, even after researchers accounted for several potential confounding factors.
The findings suggest that tea-drinking habits may be associated with cardiovascular health, although the observational research cannot establish that tea directly prevents disease.
Researchers examined several characteristics of tea consumption, including whether participants preferred black or green tea, how strongly they brewed it, the temperature at which they drank it and their typical daily intake.
Black tea demonstrated more consistent associations with lower vascular disease risk across the conditions examined than green tea, a finding that differs from the emphasis often placed on green tea in nutritional research.
Both varieties come from the Camellia sinensis plant but undergo different processing methods. Black tea is more extensively oxidized, producing changes in the composition of its naturally occurring polyphenols.
Green tea contains relatively high concentrations of catechins, while black tea contains compounds known as theaflavins and thearubigins, which also have antioxidant properties.
Researchers have investigated whether these substances influence blood pressure, inflammation, cholesterol metabolism and blood vessel function.
However, the latest study does not establish that black tea is inherently healthier than green tea or that switching varieties would reduce an individual’s cardiovascular risk.
Tea strength also appeared to influence the findings.
Participants who consumed moderately brewed tea generally demonstrated more favorable vascular outcomes than those who preferred stronger preparations.
The results suggest that increasing tea concentration does not necessarily produce additional health benefits, although researchers did not establish an optimal brewing time or standardized concentration for consumers.
One of the study’s more notable findings involved drinking temperature.
Participants who reported consuming tea at a “burning hot” temperature experienced approximately 16% higher relative vascular disease risk than those who did not regularly drink tea.
By comparison, individuals who consumed tea at less extreme temperatures generally demonstrated more favorable associations.
Although the study identified a statistical relationship, it did not establish whether extremely hot tea directly caused vascular damage or whether other factors contributed to the difference.
The findings nevertheless reinforce the practical value of allowing freshly brewed beverages to cool before drinking them.
Researchers also identified a nonlinear relationship between tea consumption and vascular health.
Among participants who drank tea at least weekly, the lowest estimated vascular disease risk occurred at approximately six to eight cups daily.
Beyond that amount, the estimated protective association weakened, suggesting that consuming progressively larger quantities did not provide additional benefits.
However, researchers cautioned against interpreting six to eight cups as a recommended daily intake.
The study relied on self-reported tea consumption, and cup sizes were not standardized. Differences in caffeine content and individual sensitivity also make it inappropriate to assume that a high daily intake would benefit everyone.
The strongest association with lower vascular disease risk appeared among participants who combined habitual tea drinking with regular physical activity and avoiding smoking.
Compared with participants who smoked, were physically inactive and did not regularly consume tea, those who drank tea, did not currently smoke and maintained high activity levels had approximately 45% lower relative vascular disease risk.
The findings highlight the importance of overall lifestyle patterns rather than any single food or beverage.
In comments published by the Science Media Centre, Dell Stanford, senior dietitian at the British Heart Foundation, said the findings contribute to existing evidence linking tea consumption with cardiovascular health but should not be interpreted as proof of a protective effect.
Stanford emphasized that dietary differences, exercise habits and other lifestyle factors could help explain the associations.
The expert also cautioned that the study’s estimated six-to-eight-cup range should not be treated as a target, particularly because participants reported their intake only once and researchers did not use standardized cup measurements.
Dr. Charalampos Rallis, a genetics and cell biology researcher at Queen Mary University of London, similarly noted that the statistical analysis did not fully account for participants’ diets or incomes.
He advised treating some findings, particularly those involving black tea and very hot tea, as exploratory until additional research confirms them.
The researchers acknowledged that their findings may not apply equally to populations outside China, where tea preparation methods, serving sizes, dietary patterns and other lifestyle factors can differ.
They also emphasized that observational studies can identify associations but cannot determine whether changing a particular habit will produce the same results.
A separate summary of the research published by Wiley noted that the study adds evidence to the potential role of habitual tea consumption in supporting vascular health.
For consumers, the findings suggest that regular consumption of moderately brewed tea at a comfortable temperature may fit into a heart-healthy lifestyle, without establishing a need to drink large quantities.
Maintaining regular physical activity, avoiding tobacco, eating a balanced diet and managing blood pressure remain established strategies for reducing cardiovascular disease risk.
The study adds to growing research examining how everyday dietary habits may influence long-term health, while underscoring that tea consumption is best considered one component of overall cardiovascular wellness rather than a substitute for proven preventive measures.
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