Tea has been touted as medicine for centuries, and modern research has linked it to better cardiovascular health. A new study suggests tea drinkers live longer, and while the findings are encouraging, scientists caution against viewing tea as a magic health bullet.

Conventional tea is made from the leaves of an evergreen shrub called Camellia sinensis. Habitual drinkers of this tea in China have a 22% lower risk of fatal heart disease or stroke, and 15% lower risk of premature death by any cause, compared to those who seldom if ever drink tea, the new research showed. Those figures rose to 56% and 29%, respectively, for people who kept up their tea habit over time, based on surveys 8.2 years apart.

In one example of how the benefits could play out, the analysis indicates that on average, 50-year-olds who drink tea habitually — defined as at least three times a week — develop coronary heart disease or stroke 1.41 years later and live 1.26 years longer than those who seldom or never drink tea.

The study, detailed in the European Journal of Preventive Cardiology, involved data on 100,902 Chinese people across 7.3 years.

Smoking, drinking, physical activity, diet, and other potential confounding factors were accounted for and not likely to have biased the results, says the study’s senior author, Dr. Dongfeng Gu, an epidemiologist at Fuwai Hospital in Beijing and member of the Chinese Academy of Medical Sciences. Still, Gu tells Elemental, the results can’t prove cause and effect, and other unaccounted-for lifestyle factors could play a role.

The protective effect of tea is thought to come from certain plant-based chemicals, including flavonoids and other polyphenols unique to tea, Gu explains. These nutrients act as antioxidants when ingested, and are thought to battle inflammation and otherwise support the immune system, battling dastardly free radicals that can damage DNA. Flavonoids are also common in many fruits and vegetables, including apples, blueberries, and broccoli, as well as in chocolate and red wine.

The body does not retain the potentially protective chemicals for long, Gu and his colleagues say. “Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect,” Gu says.

The study found green tea to be more effective than black tea (both are made from the same plant, with black tea being more highly processed.) But only 8% of the people in the study habitually drank black tea, compared to 49% who preferred green. “The small proportion of habitual black tea drinkers might make it more difficult to observe robust associations, but our findings hint at a differential effect between tea types,” Gu says.

Other research suggests both types of tea can be good for you.

“There is strong evidence for the benefits of both black and green tea consumption on heart health,” says Nicola Bondonno, Ph.D., a health science researcher at Edith Cowan University in Australia. “Among other things, tea has been shown to reduce blood pressure, improve blood vessel function, and improve cholesterol.”

Bondonno’s research, including a November 2019 study in The Lancet Planetary Health journal and a separate August 2019 study in Nature Communications, has linked diets rich in flavonoids (with tea being a primary contributor) to lower risk of death from cancer, heart disease, and all causes. But in studying the Danish population, she found black tea far more commonly consumed than green.

David Middleton, Ph.D., a chemistry professor at Lancaster University in England, cautions against leaping to conclusions over any potential miracles of tea, however.

“Any statement like ‘tea drinkers live longer’ should be treated with caution,” Middleton says. The new findings “add to a growing body of data that suggest positive effects of tea consumption on cardiovascular health,” he says. “However, like previous work, the results are not conclusive and do not definitively establish a link between tea drinking and the causes of heart disease. Indeed, some previous studies failed to show a positive effect. The striking feature of this work is a large number of subjects,” which improves the statistical power, “but nevertheless the results raise more questions than they answer.”

Middleton and colleagues, in a 2018 study, found that a flavonoid molecule in green tea (called epigallocatechin-3-gallate) dissolves plaque that can form in blood vessels, which unchecked can lead to a heart attack or stroke. He considers his findings and the new results complementary, but not conclusive.

“We know that certain molecules in tea have antioxidant and anti-inflammatory properties, which could protect against heart disease, but the body rapidly modifies these molecules when they enter the bloodstream,” Middleton explains. “What is not known is whether these modified molecules are protective, too. This new study suggests that perhaps they are, but more work is needed to confirm this.”

Given the evidence, tea would seem a wise health insurance policy, especially as a substitute for soda or other nutritionally hollow, sweetened drinks… so long as you take your tea straight. “Just be careful that you are not increasing your sugar intake by increasing your tea intake,” Bondonno advises.