Drinking Tea Reduces the Risk of Death From Cardiovascular Disease

Many health benefits of drinking tea have been reported, but most studies were conducted in areas where green tea is more common. New data from England, home to the afternoon tea tradition, now suggest that black tea also offers health benefits.

A Study in the Second-Largest Tea-Consuming Population 

Turkey has the world’s highest tea consumption per person, followed by the United Kingdom.

Prospective findings came from a UK Biobank study involving nearly 500 thousand participants , predominantly in a population where black tea consumption is common. Annals of Internal Medicine published the study, which linked black tea drinking to a modest reduction in all-cause mortality. The benefit was most evident among people drinking two or more cups daily.

Maki Inoue-Choi and colleagues at the National Cancer Institute in Bethesda, Maryland, reported lower all-cause mortality among people drinking at least two cups daily during a median follow-up of 11.2 years. In analyses considering many variables, mortality hazard ratios for tea drinkers were compared with those for nondrinkers.

Hazard ratios by daily tea consumption were as follows (a lower hazard ratio means lower risk):

• 1 cup: hazard ratio 0.95
• 2-3 cups: hazard ratio 0.87
• 4-5 cups: hazard ratio 0.88
• 6-7 cups: hazard ratio 0.88
• 8-9 cups: hazard ratio 0.91
• 10 or more cups: hazard ratio 0.89

Tea consumption was also associated with a lower risk of cardiovascular disease, ischemic heart disease and stroke . However, the researchers added that “there was no clear trend toward a lower risk of death from cancer or respiratory disease” .

Inoue-Choi said there was “no clear answer” as to why no association between tea consumption and cancer mortality was observed.

The effects were evident regardless of milk or sugar added to tea, tea temperature or genetic variations in caffeine metabolism. The team adjusted for these and many other potential confounders, including coffee consumption and baseline health and demographic characteristics.

The 498,093 adults had a mean age of 56.5. Approximately 85% reported drinking tea, and 90% reported drinking black tea. Most consumed 2-3 cups (29%), 4-5 cups (26%) or 6-7 cups (12%) daily. The researchers highlighted the lack of information on serving size and tea strength as study limitations.

How Reliable Are the Results?

Tea is among the world’s most consumed drinks. Studies from China and Japan, where green tea is popular, have shown health benefits. Until now, data from places where black tea is more common have been limited and inconsistent.

The researchers explain the proposed mechanism of tea consumption as the action of “polyphenols and flavonoids, namely catechins and their oxidized products,” reducing oxidative stress and inflammation . They add that oxidative stress and inflammation can promote carcinogenesis and cardiovascular disease, so reducing them may improve endothelial function.

Inoue-Choi said, “Although these findings may reassure tea drinkers, they do not indicate that people should start drinking tea or change their consumption within healthy limits. The results need replication in future studies and extension to other populations” .

In conclusion, this largest prospective study of the health effects of black tea, Turkey’s most widely consumed beverage, offers promising results and supports further research. The rising cost of coffee, an imported product, may also motivate a return to tea. However, care should be taken not to drink tea too hot or too strong, or after leaving it to stand too long.