People who love their green tea may also enjoy longer, healthier lives, a large new study suggests.
Researchers found that of more than 100 000 Chinese adults they tracked, those who drank green tea at least three times a week were less likely to suffer a heart attack or stroke over the next seven years.
Various health benefits
Tea lovers also had a slightly longer life expectancy. At age 50, they could expect to live just over a year longer than their counterparts who were not regular consumers of green tea.
The study is the latest to look at green tea's potential health effects.
Over the years, many studies have linked the beverage to benefits like healthier cholesterol levels and body weight, and lower risks of heart disease and certain cancers.
Those studies, like the current one, were "observational" – where researchers ask people about their lifestyle habits and other factors, then follow their health outcomes. The limitation is they do not prove that green tea, itself, provides any benefits.
Green-tea drinkers may differ from non-consumers in other ways. Research in the United States has found that tea drinkers (all types of tea) generally have healthier diets than non-drinkers, said Whitney Linsenmeyer, an assistant professor of nutrition at Saint Louis University.
Researchers do try to account for such differences. In the current study, the investigators were able to weigh overall diet, exercise habits, smoking and education level, among other factors.
Evidence from clinical trials
Still, it's impossible to control for everything, said Linsenmeyer, who is also a spokesperson for the Academy of Nutrition and Dietetics.
That said, a number of studies across different countries have now found health benefits among green-tea drinkers, according to Linsenmeyer.
Plus, there's some evidence from clinical trials. Linsenmeyer pointed to a recent trial of Iranian women finding that those who drank three cups of green tea a day saw improvements in weight, blood pressure, blood sugar and cholesterol over eight weeks.
So if you're a green-tea fan, drink up, advised Linsenmeyer.
"Green tea is calorie-free and antioxidant-rich," she said. "It's a healthy beverage to include in your diet if you like the taste."
Higher in antioxidants
It does contain caffeine, though. "So be wary if you take medications that interact with caffeine, or if you struggle with insomnia," Linsenmeyer said.
The findings were published online in the European Journal of Preventive Cardiology. The study was based on 100 902 Chinese adults who were free of heart disease and cancer at the outset. The participants were interviewed about their lifestyle habits and medical history, and had their weight, blood pressure and cholesterol measured.
Over the follow-up period – typically seven years – almost 3 700 suffered a heart attack or stroke, or died of cardiovascular causes. The risk was 20% lower, however, among those who habitually drank green tea (at least three times a week).
Those habitual consumers were also 15% less likely to die of any cause, versus people who drank green tea less often or not at all.
Green, black and white tea all come from the same plant, but there are differences in how they are made. And compared with black tea – which is more popular in the United States – green tea is higher in antioxidants called flavonoids, according to the study authors.
Calorie-free form of hydration
Lab experiments suggest green-tea extracts can quell inflammation and improve functioning of cells in the blood vessels and heart, the researchers said. The team was led by Dr Xinyan Wang, of the Chinese Academy of Medical Sciences, in Beijing.
For now, the jury is still out on whether adding green tea to your diet will ward off any diseases, said Connie Diekman. She's a food and nutrition consultant and past president of the Academy of Nutrition and Dietetics.
But Diekman said she often encourages people to go ahead and enjoy their tea, since it's a calorie-free form of hydration (provided it's not loaded with sugar or cream).
"Adding [green tea] to your daily routine can't hurt, and it might help," Diekman said.
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