The study showed that those who drank 2 or more cups of black tea daily had a 9 to 13 percent reduction in all-cause mortality compared with those who did not drink tea. The study was published in the Annals of Internal Medicine.
Washington, D.C. (Merxwire) - In the past, "polyphenols" were found in green tea and believed to have antioxidant effects, so many health-conscious people started drinking green tea. However, green tea easily irritates the stomach and is not suitable for patients with stomach problems; the good news is that scientists have found that drinking black tea is also beneficial to human health!
The National Institutes of Health (NIH) used data from the UK Biobank to analyze questionnaires from nearly 500,000 participants between 2006 and 2010. The participants, men and women aged 40-69, underwent physical examinations and provided blood, urine, and saliva samples at participation.
Participants responded to lifestyle and health-related information in a questionnaire that included the number of cups of tea they drank daily. Most participants said they had the habit of drinking tea, of which 89% drank black tea, and 7% drank green tea. And most of them drink 2 to 5 cups of tea a day, and about 19% drink more than 6 cups a day.
The researchers analyzed the relationship between tea intake and mortality from the data, including cancer, cardiovascular disease, respiratory disease, etc. The results showed that those who drank 2 or more cups of tea daily had a lower risk of death by 9-13% compared to those who did not drink tea. Also, adding milk or sugar to the tea, whether hot or cold, did not change the association.
"The results reinforce that tea, including black tea, can be part of a healthy diet," Dr. Erikka Loftfield said in a press release. However, the researchers also cautioned that the study was observational and could not prove that drinking tea directly reduced the risk of death. They did not assess the concentration of tea and cup size, and further research is needed.
What is the difference between green tea and black tea? The degree of fermentation of the tea leaves can produce different concentrations of green or black tea. Green tea is unfermented or only partially fermented and retains more tannins, catechins, theophylline, etc. Although these substances have antioxidant properties, they are irritating to the stomach.
Black tea is completely fermented. During fermentation, enzymes convert most of the catechins and tannins into "condensed tannins," so the tea color is dark red. Since fermentation reduces the polyphenol content, black tea is less irritating to the stomach than green tea. However, black tea usually contains more caffeine than green tea, so remember not to consume too much black tea in the afternoon tea, to avoid difficulty falling asleep at night.