A large prospective study following more than 42,000 people in northern Vietnam for about 11 years found that heavier green tea consumption was associated with substantially lower all-cause mortality, although researchers cautioned that the observational design cannot prove tea itself caused the difference.
By yourNEWS Media Newsroom.
People who regularly drank larger amounts of green tea had a lower risk of dying during more than a decade of follow-up in a major Vietnamese study, adding to a growing body of research examining whether traditional tea consumption is associated with longer life.
The prospective cohort study included 42,146 participants in northern Vietnam and tracked them from 2007 through 2019. Researchers recorded 2,494 deaths during a median follow-up period of about 11 years.
Participants reported their green tea consumption through a validated food-frequency questionnaire at the start of the study. Researchers then compared mortality rates across intake categories while statistically adjusting for factors including age, smoking, alcohol use, body mass index, education and several dietary variables.
Those in the highest green tea consumption group had about a 26% lower risk of death from any cause than participants in the lowest-consumption group, according to the published analysis.
Researchers also found a broader dose-response pattern: Mortality risk generally declined as green tea consumption increased. Across the full population, each standard-deviation increase in green tea intake was associated with a 7% reduction in mortality risk.
That pattern was observed among younger and older participants, people with lower body mass indexes, smokers and nonsmokers, alcohol drinkers and people both with and without a history of type 2 diabetes.
The association appeared somewhat clearer among men. In women, the direction of the relationship was similar, but the result did not reach statistical significance.
The researchers described the findings as supportive of a possible protective role for green tea but emphasized the need for additional studies in other populations.
Because the study was observational, it cannot establish that green tea itself caused participants to live longer.
People who drink tea can differ from non-tea drinkers in numerous ways that influence health, including diet, physical activity, income, healthcare use and other lifestyle patterns. Statistical adjustments can reduce those differences but cannot eliminate every possible source of confounding.
The researchers also measured tea intake primarily from dietary information collected at baseline rather than repeatedly tracking consumption throughout the full follow-up period, meaning participants’ habits may have changed.
Still, the study’s large sample, long follow-up and graded relationship between higher intake and lower mortality add weight to earlier research examining tea and longevity.
A previous Chinese cohort involving roughly 100,000 adults similarly found that habitual tea consumption, particularly green tea, was associated with lower risks of cardiovascular disease and all-cause mortality. That research also remained observational and therefore could not prove cause and effect.
Scientists have proposed several biological mechanisms that could help explain the association.
Green tea contains high concentrations of polyphenols known as catechins. One of the most heavily studied is epigallocatechin gallate, or EGCG.
Experimental research has found that catechins can influence oxidative stress, inflammation, blood-vessel function and several metabolic pathways. Those effects have made green tea a frequent subject of research involving cardiovascular disease, diabetes and certain cancers.
Green tea undergoes relatively little oxidation during processing compared with black tea, helping preserve larger quantities of catechins.
That does not mean more tea is always better.
A separate 2025 review in Beverage Plant Research examined both potential benefits and possible concerns associated with tea consumption and drew an important distinction between traditionally brewed tea and heavily processed commercial drinks.
Researchers noted that bottled teas and bubble teas can contain substantial amounts of added sugar, artificial sweeteners, refined starches, flavorings and preservatives.
Bubble tea can be especially calorie-dense because tapioca pearls are commonly soaked in sucrose or high-fructose corn syrup, while some formulations include non-dairy creamers containing saturated fats.
The authors concluded that those added ingredients could diminish or overshadow some of the health advantages associated with tea itself.
Freshly brewed unsweetened tea therefore differs nutritionally from a bottled product containing large quantities of sugar or a dessert-style bubble tea.
The review also examined concerns about contaminants.
Researchers noted that pesticide residues, heavy metals and microplastics have been detected in some tea products. However, the actual health risk depends on how much of those substances passes from the leaf into the brewed beverage.
For most conventionally brewed tea, available risk assessments have generally concluded that ordinary consumption does not expose people to dangerous quantities of those contaminants.
The review estimated that exposure to microplastics through loose-leaf tea itself was extremely low.
Plastic tea bags were a different concern. Some research has found that steeping certain plastic-based tea bags in very hot water can release large numbers of microscopic plastic particles, though the clinical significance of that exposure remains uncertain.
Tea also can affect the absorption of certain nutrients.
Polyphenols in tea can reduce absorption of non-heme iron, the form of iron found primarily in plant foods. The effect is most relevant when tea is consumed with meals.
That may matter particularly for vegetarians, people with low iron stores or those already at risk for iron-deficiency anemia.
The review found no clear evidence that moderate tea consumption meaningfully impairs calcium absorption in otherwise well-nourished people. Studies examining tea and bone health have produced inconsistent results, and moderate intake has generally not been linked to lower bone density when calcium intake is adequate.
Heavy consumption and concentrated tea supplements raise different safety questions.
Ordinary brewed tea has a long history of use and generally has not been associated with serious toxicity in humans. Concentrated green tea extracts, however, can deliver much larger doses of catechins than a typical beverage.
Some clinical studies involving high-dose extracts have reported elevations in liver enzymes, and rare cases of liver injury have been associated with concentrated green tea supplements.
That distinction makes it important not to treat a cup of brewed green tea and a high-dose extract capsule as equivalent.
The Vietnamese research specifically examined habitual dietary consumption rather than concentrated supplements.
One other limitation is that the highest intake category in the study did not necessarily represent the extremely large volumes associated with heavy tea drinking in some other populations. The top group reported a mean intake of roughly 73.5 milliliters per day under the study’s dietary measurement system, while most participants fell into the lowest category.
That unusual distribution means the findings should be interpreted within the context of the Vietnamese population studied rather than translated into a universal number of cups people should drink each day.
Researchers did not establish an optimal dose or recommend a specific daily quantity.
The study’s strongest conclusion is therefore narrower than simply saying green tea extends life.
Among more than 42,000 people followed for roughly 11 years, those reporting greater green tea intake consistently showed lower rates of death after researchers accounted for numerous other factors.
That relationship fits with previous studies and with laboratory evidence suggesting green tea compounds can influence cardiovascular and metabolic processes.
Whether green tea itself is responsible for the difference, how much would be needed to produce a meaningful benefit, and whether the same results would appear in other populations remain unanswered questions.
For people who already enjoy tea, the research supports unsweetened, traditionally brewed green tea as a reasonable beverage choice within an otherwise healthy diet.
But the evidence does not turn tea into a prescription for longevity — and it does not mean sugary bottled tea, bubble tea or concentrated supplements provide the same potential benefits.
Source: Natural News
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