A comprehensive review in Beverage Plant Research concludes that evidence from human studies most strongly supports an association between tea consumption—particularly green tea—and lower risks of cardiovascular disease, obesity, type 2 diabetes and some cancers, while calling evidence for brain and muscle benefits “promising” but less settled. The authors also caution that bottled and bubble tea products, which can include added sugar and other additives, may blunt tea’s potential advantages.
Tea, produced from the leaves of Camellia sinensis, has a long history of use and was initially consumed in China for medicinal purposes before becoming a widely enjoyed beverage, according to a review published in Beverage Plant Research.
The review—authored by Mingchuan Yang, Li Zhou and colleagues at the Tea Research Institute of the Chinese Academy of Agricultural Sciences, with a co-author at Rutgers University—evaluates evidence on tea’s health effects, giving the most weight to human research such as large cohort studies and randomized controlled trials, while treating laboratory and animal studies as supportive for understanding possible mechanisms.
Strongest evidence: cardiovascular disease and related metabolic conditions
The authors say the “most convincingly observed” health benefit tied to tea consumption is prevention of cardiovascular diseases, and they also describe solid evidence linking tea intake with lower risks of obesity, type 2 diabetes and some types of cancer. The paper notes that many findings in this area come from studies of green tea, and that a meta-analysis of prospective cohort datasets reported lower mortality risks (all-cause, cardiovascular and cancer) at moderate tea intake levels.
The review also summarizes evidence suggesting green tea can help lower blood pressure and improve cholesterol profiles, and that catechins—a major class of tea polyphenols—may contribute to observed effects. While many randomized trials in overweight or obese adults have reported weight-related improvements with green tea or tea catechin intake, the authors also highlight that not all studies align: they cite some evidence—including findings from large Shanghai cohort studies—showing tea consumption was associated with higher type 2 diabetes risk in that specific setting, and note that trials in people with diabetes have not consistently shown improvements in measures such as blood sugar control.
Emerging areas: brain health and muscle loss in aging
Beyond cardiovascular and metabolic outcomes, the review describes research on cognitive decline and age-related muscle loss as “promising” but in need of additional study in humans. It points to findings suggesting tea consumption may be associated with reduced cognitive decline and possible changes in biomarkers linked to Alzheimer’s disease, and that catechins could have a role in slowing muscle loss in older adults.
The authors also discuss tea’s antimicrobial and anti-inflammatory activities as additional potential benefits supported by a mix of human and laboratory evidence.
Processed tea products and contaminants
Not all tea products are equivalent, the review cautions. It argues that bottled tea and bubble tea beverages may include added sugar, artificial sweeteners, refined starch, flavoring agents and preservatives—ingredients the authors say could reduce or overshadow tea’s beneficial effects.
The paper also reviews concerns about pesticide residues, heavy metals and other contaminants. It says risk assessments based on levels measured in tea brews suggest that regular tea consumption should not pose a health risk for the general population, though it notes that higher exposure over long periods or specific health conditions could change risk considerations.
Finally, the review discusses nutrient interactions, stating that tea drinking can reduce absorption of non-heme iron from plant-based foods—a consideration the authors say may be particularly relevant for vegetarians or others with specific nutritional needs.
What the authors recommend next
The authors conclude tea is generally an enjoyable and healthy beverage, but emphasize that more research is needed to clarify long-term effects, compare health impacts across tea types (including black, oolong and white tea), and better characterize how additives and contaminants affect health across different populations.
