Tea health benefits suggested: National Cancer Institute observational study finds black teak, like green tea, might also offer health benefits

Alastair Grant / AP

People who drink black tea might be a little more likely to live longer than those who don’t, according to a large, new study.

Tea contains substances known to reduce inflammation. Past studies in China and Japan, where green tea is popular, suggested health benefits. The new study, though not definitive, suggests the same for black tea — the United Kingdom’s favorite drink.

Scientists from the National Cancer Institute used a large database project that asked about the tea habits of nearly a half million adults in the U.K., then followed them for up to 14 years, adjusting for risk factors such as health, socioeconomics, smoking, alcohol intake, diet, age, race and gender.

Having a higher tea intake — two or more cups a day — was linked to a modest benefit: a 9% to 13% lower risk of death from any cause vs. non-tea drinkers. 

The study, published in the Annals of Internal Medicine, found the association held up for heart disease deaths, but there was no clear trend for cancer deaths. The researchers weren’t sure why, but it’s possible there weren’t enough cancer deaths for any effect to show up, said Maki Inoue-Choi, who led the study.

A study like this, based on observing people’s habits and health, can’t prove cause and effect.

“Observational studies like this always raise the question: Is there something else about tea drinkers that makes them healthier?” said Marion Nestle, a professor of food studies at New York University. “I like tea. It’s great to drink. But a cautious interpretation seems like a good idea.”

There’s not enough evidence to advise changing tea habits, according to Inoue-Choi.

“If you drink one cup a day already, I think that is good,” she said. “And please enjoy your cup of tea.”