Drinking black tea lowers mortality risk

Key takeaways

• People who drank 2 or more cups of tea each day had a 9% to 13% lower all-cause mortality risk compared with those who did not drink tea.
• High tea intake was also associated with lower risks for mortality from CVD, stroke and ischemic heart disease.
• The risk for mortality decreased with higher tea intake, but the benefit plateaued at 2 to 3 cups per day.

Drinking just 2 cups of tea every day may lower one’s mortality risk, according to a study published in Annals of Internal Medicine.

Tea, one of the most popular drinks in the world, according to researchers, has previously been linked to a lower mortality risk in populations where green tea is the most common type consumed. Black tea has previously been linked to a lower risk for fractures in older women and lower levels of liver stiffness, but there is limited and inconsistent evidence on mortality risk in populations where black tea is more commonly consumed, according to Maki Inoue-Choi, PhD, MS, RD, a scientist with the NIH’s National Cancer Institute, and colleagues. Therefore, the researchers sought to better understand the association between mortality and tea consumption, and how variables like different temperatures, the rate at which the participants metabolize caffeine, or adding milk and sugar, might affect mortality risk.

Inoue-Choi and colleagues conducted the prospective cohort study with data from the U.K. Biobank, “where black tea consumption is common,” the researchers wrote. They analyzed questionnaires from 498,043 participants aged 40 to 69 years — about 94% of whom were white. The questionnaires asked about lifestyle, health-related and sociodemographic information. The participants also provided saliva, urine and blood samples and underwent a physical examination.

Almost 85% of participants who completed the baseline 24-hour dietary recall questionnaire reported drinking tea and, of those, 89% drank black tea, according to the Inoue-Choi and colleagues.

The researchers found that most participants drank 2 to 3 cups (29%), 4 to 5 cups (26%) or 6 to 7 cups (12%) of tea per day, and “the relationship between tea drinking and some potential risk factors was complex.”

When compared with those who did not drink tea, the participants who drank 2 or more cups each day had a 9% to 13% lower all-cause mortality risk. People who drank tea were more likely to be obese men living in England, report fair or poor general health and eat more red and processed meat, compared with non-frequent tea drinkers.

When the researchers performed a spline analysis, they reported discovering “a nonlinear association between tea intake and all-cause mortality, with risk decreasing with higher tea intake but plateauing at 2 to 3 cups per day.”

The HRs for lower mortality risk among those who reported drinking tea vs. those who did not were:

• 0.95 (95% CI, 0.91-1) for 1 or fewer cups daily;

• 0.87 (95% CI, 0.84-0.91) for 2 to 3 cups daily;

• 0.88 (95% CI, 0.84-0.91) for 4 to 5 cups daily;

• 0.88 (95% CI, 0.84-0.92) for 6 to 7 cups daily;

• 0.91 (95% CI, 0.86-0.97) for 8 to 9 cups daily; and

• 0.89 (95% CI, 0.84-0.95) for 10 or more cups daily.

The findings were similar regardless of whether participants also drank coffee, added milk or sugar to their tea, their preferred tea temperature or genetic variants related to caffeine metabolism.

The authors wrote that their findings “provide reassurance to tea drinkers and suggest that black tea can be part of a healthy diet.”

“In this prospective analysis ... where more than four of five adults habitually drank tea, higher tea intake was modestly associated with lower mortality risk during a median of 11.2 years of follow-up, including among participants who reported adding milk or sugar to tea and among those with a slower genetically inferred caffeine metabolism rate,” the researchers wrote. “Lower risks with higher tea intake were also seen for mortality from overall CVD, ischemic heart disease and stroke.”

References:

• Drinking black tea may be associated with lower mortality risk. https://www.acpjournals.org/journal/aim/tip-sheets. Published Aug. 29, 2022. Accessed Aug. 29, 2022.
• Inoue-Choi M, et al. Ann Intern Med. 2022;doi:10.7326/M22-0041.