Bottoms Up on Black Tea for a Long Life?

A few cups of tea a day might help to stave off an early death, a U.K. Biobank prospective cohort study showed.

Among nearly half a million middle-age adults, those who consumed two or more cups of tea a day saw a modest but lower risk for all-cause mortality over a median 11.2-year follow-up, reported Maki Inoue-Choi, PhD, of the National Cancer Institute in Bethesda, Maryland and colleagues in the Annals of Internal Medicine.

While those who only drank one or fewer cups per day didn’t see this protective benefit (HR 0.95, 95% CI 0.91-1.00), moderate and heavy tea drinkers did see a significantly lower mortality risk:

• Two to three cups per day: HR 0.87 (95% CI 0.84-0.91)
• Four to five cups: HR 0.88 (95% CI 0.84-0.91)
• Six to seven cups: HR 0.88 (95% CI 0.84-0.92)
• Eight to nine cups: HR 0.91 (95% CI 0.86-0.97)
• 10 or more cups: HR 0.89 (95% CI 0.84-0.95)

“Almost 90% drank black tea, making black tea the predominant tea type in this population,” Inoue-Choi pointed out during a press conference. She added that most previous research quantifying the benefits of tea drinking have focused on green, not black, tea.

“These results suggest that black tea, even at higher levels of intake, can be part of a healthy diet,” she said. “While these findings offer reassurance to tea drinkers, they do not indicate that people should start drinking tea or change their tea consumption for health benefits.”

Inoue-Choi’s group also found that drinking tea was linked with a lower risk for cardiovascular-specific causes of death.

In fully adjusted models for sociodemographic and lifestyle factors, drinking more than two cups of tea per day was associated with a 14% to 24% lower risk for death from all cardiovascular diseases, with the heaviest tea drinkers seeing the most risk reductions.

Likewise, consuming two to three cups per day was linked with a 17% lower risk for death due to ischemic heart disease, although those who drank anywhere from four to seven cups on average didn’t see a significant risk reduction. However, drinking eight or more cups on average was associated with a 26% lower risk for ischemic heart disease-related mortality.

As for stroke-related deaths, only those who drank 10 or more cups per day saw a significant risk reduction (HR 0.48, 95% CI 0.28-0.85).

Drinking an average of two to three cups of tea per day was also linked with a modestly reduced risk for respiratory disease-related death and cancer-related death.

Inoue-Choi added that these associations were seen regardless of tea temperature and whether people took their tea black or if they added milk and/or sugar. The associations were also adjusted for genetic variations in caffeine metabolism.

“Tea is very rich in bioactive compounds, such as polyphenols,” she told MedPage Today. “These compounds have the potential to decrease oxidative stress and inflammation, so these mechanisms can protect against cancer, cardiovascular disease, and other health conditions.”

For this analysis, the researchers assessed data on 498,043 men and women from the U.K. Biobank, ranging in ages from 40 to 69, who completed the baseline touchscreen questionnaire from 2006 to 2010. More than 90% of respondents were white.

Of this cohort, 85% said they consumed tea daily, with 11.5% drinking one cup or less, 29.4% drinking two to three cups, 25.5% drinking four to five cups, 11.8% drinking six to seven cups, 3.7% drinking eight to nine cups, and 3.4% drinking 10 or more cups.

Men were a bit more likely to be the heaviest tea drinkers. Those drinking 10 or more cups of tea per day were also most likely to be current smokers.

“Although the associations were assessed carefully and comprehensively, these results need to be replicated in future studies and extended in other diverse populations,” Inoue-Choi suggested.

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