Summary: Researchers report that drinking two or more cups of black tea per day is linked with a modestly lower risk of death from all causes.
Source: American College of Physicians
A large prospective cohort study from the U.K. Biobank found that regular consumption of black tea was associated with a moderate reduction in mortality risk, with the greatest benefit observed among people who drank two or more cups daily.
The results are published in Annals of Internal Medicine.
Tea is one of the world’s most widely consumed beverages. Prior research has linked tea drinking—often green tea in some populations—to lower mortality, but evidence has been mixed in populations that primarily drink black tea. To address this gap, researchers from the National Institutes of Health analyzed data from the U.K. Biobank, a large, well-characterized sample where black tea is the predominant type consumed.
The study evaluated how self-reported tea intake related to death from any cause as well as specific causes such as cardiovascular disease, ischemic heart disease, stroke, respiratory disease, and cancer. The team also examined whether common tea additives (milk or sugar), preferred tea temperature, and genetic differences in caffeine metabolism modified the associations.
The U.K. Biobank cohort includes nearly half a million men and women aged 40 to 69 who completed a baseline questionnaire between 2006 and 2010. In this sample, 85 percent reported regularly drinking tea and, of those, 89 percent indicated black tea as their usual type.
Compared with participants who did not drink tea, those who reported drinking two or more cups per day experienced a modestly lower risk of death during follow-up. Overall, relative risks correspond to reductions in mortality on the order of roughly 9 to 13 percent for regular tea drinkers in the 2-plus cups per day range.
Importantly, the observed associations held regardless of whether participants also drank coffee, added milk or sugar to their tea, or preferred their tea at a particular temperature. The patterns also did not differ meaningfully across groups defined by genetic variants that influence the speed of caffeine metabolism.
The study authors conclude that drinking black tea, even at higher levels of consumption, can be compatible with a healthy diet and may contribute to modest reductions in mortality risk, particularly for cardiovascular outcomes.
About this mortality research news
Author: Angela Collom
Source: American College of Physicians
Contact: Angela Collom – American College of Physicians
Image: The image is in the public domain
Original Research: Closed access.
“Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank” by Maki Inoue-Choi et al. Annals of Internal Medicine
Abstract
Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank
Background:
Although tea is commonly consumed worldwide, evidence on how tea drinking relates to mortality in populations where black tea is the primary type remains inconclusive.
Objective:
To assess associations between tea consumption and risk of death from all causes and specific causes, and to evaluate whether genetic differences in caffeine metabolism modify those associations.
Design:
Prospective cohort study using data from the U.K. Biobank.
Setting:
UK Biobank, a large population-based cohort in the United Kingdom.
Participants:
498,043 men and women aged 40 to 69 years who completed a baseline touchscreen questionnaire between 2006 and 2010.
Measurements:
Self-reported tea intake and records of mortality from all causes and major categories of death, including cancer, cardiovascular disease (CVD), ischemic heart disease, stroke, and respiratory disease.
Results:
Over a median follow-up of 11.2 years, higher tea consumption was modestly associated with lower all-cause mortality among participants who drank two or more cups per day. Compared with non–tea drinkers, hazard ratios (95% confidence intervals) were: 0.95 (0.91 to 1.00) for 1 or fewer cups/day; 0.87 (0.84 to 0.91) for 2–3 cups/day; 0.88 (0.84 to 0.91) for 4–5 cups/day; 0.88 (0.84 to 0.92) for 6–7 cups/day; 0.91 (0.86 to 0.97) for 8–9 cups/day; and 0.89 (0.84 to 0.95) for 10 or more cups/day. Inverse associations were also observed for deaths due to all cardiovascular disease, ischemic heart disease, and stroke. Results were consistent regardless of coffee drinking status or genetic score for caffeine metabolism.
Limitation:
The study did not collect detailed information on certain aspects of tea intake, such as portion size and tea strength, which could influence exposure assessment.
Conclusion:
Higher tea intake—particularly two or more cups per day—was associated with modestly lower all-cause mortality in this large U.K. cohort, independent of genetic variation in caffeine metabolism. These findings support the idea that black tea can be included as part of a healthy dietary pattern.
Primary Funding Source:
National Cancer Institute Intramural Research Program.