Drinking black tea may lower your risk of death, according to a new study published in Annals of Internal Medicine.
The researchers examined data on nearly 500,000 people aged 40-69 from the UK Biobank, a long-term database that has been tracking genetics and health information since 2006. They found that drinking at least two cups of black tea per day was associated with a 9%-13% lower risk of death from all causes, compared to not drinking tea at all.
Maki Inoue-Choi, PhD, MS, RD, an epidemiologist at the National Cancer Institute and lead researcher of the study, said that black tea is rich in flavonoids and polyphenols, which may decrease stress and inflammation and lower the risk of developing certain health conditions.
"If you are already drinking a cup of tea every day, please continue enjoying your cup of tea and be reassured that it is part of a healthy diet," Inoue-Choi told Verywell in an email.
She added that further studies are needed to investigate how black tea might benefit health. While these findings are encouraging for tea drinkers, people who don't normally drink tea shouldn't change their dietary habits based on one study.
Colleen Tewksbury, PhD, MPH, RDN, a spokesperson for the Academy of Nutrition and Dietetics, said that observational studies like this one help scientists determine what to focus their research on in the future. However, to truly determine whether black tea helps expand lifespan, randomized controlled trials are needed.
Tewksbury said that the caffeine in black tea could be a "drawback" for heart health. As with any food or drink, the answer to whether black tea is healthy is more nuanced.
"It's one food or one beverage in the grand scheme of what else are you consuming, how much, how often, and for you individually, what your nutrition needs are," Tewksbury said.
According to the study, the benefits of black tea stayed the same even if people added milk and sugar to their cups of tea. Inoue-Choi said this was likely because the participants added a relatively small amount of milk and sugar on average. And the sugar and fat content might only reflect a fraction of someone's overall dietary pattern.
With only observational data, it's impossible to make solid recommendations for tea consumption, Tewksbury said, especially since this study didn't assess tea strength or portion size.
More research and randomized controlled trials with large, diverse samples are necessary before health professionals can confidently recommend black tea as part of a healthy diet.
Black tea doesn't appear to be harmful to most people but there isn't enough evidence to say that it helps extend lifespan.