My morning routine isn’t complete without two cups of green tea that are both soothing and energizing.
Not only is a cup of tea very pleasant, but it has long been associated with health benefits, including a lower risk of heart disease, stroke and dementia. A new study published Wednesday in the Journal of Internal Medicine suggests that the way people prepare and drink their tea may also influence their cardiovascular health.
Over an average follow-up of about nine years, researchers documented more than 14,800 cases of diseases affecting the heart and blood vessels, such as heart attacks, strokes and peripheral artery disease, which involve narrowing of the arteries supplying blood to the arms and legs.
Researchers analyzed data from more than 485,000 Chinese adults aged 30 to 79. Participants reported their tea drinking habits, including how often they drank tea, what type they preferred, how strongly they brewed it, and how hot they drank it.
To help us understand the findings and what they mean for heart health, I spoke with CNN wellness expert Dr. Leana Wen. Wen is an emergency physician and clinical associate professor at George Washington University. She previously served as Baltimore’s health commissioner.
CNN: What did this new study reveal about tea consumption and cardiovascular disease?
Dr. Leana Wen: A major finding was that people who drank tea at least three days a week had about an 11% lower risk of developing vascular disease compared to those who drank it less frequently. This was after taking into account factors such as age, smoking, physical activity, body weight and existing health problems – although non-smokers who habitually consumed tea and engaged in high physical activity had the lowest cardiovascular rate. risk.
Another interesting finding is that moderate strength tea was associated with lower risk, and black tea was associated with lower risks for more types of cardiovascular disease than green tea. Perhaps most surprising is that people who reported drinking their tea at a “hot” temperature had a 16% higher risk of vascular disease than those who didn’t drink tea regularly. In contrast, people who drank tea at room temperature or hot – but not hot – had a significantly lower risk than those who did not drink tea regularly.
However, a limitation of the research methods was that participants described their preferred drinking temperature through self-reports, rather than the study authors objectively measuring this factor. What one person considers hot may be very different from another person’s definition. It’s also possible that people who prefer hot tea differ in other ways that influence their cardiovascular risk, such as dietary habits or other lifestyle factors that researchers haven’t been able to fully take into account.
CNN: How is drinking tea beneficial for heart health?
Magnifying glass: Tea contains natural compounds called polyphenols, including flavonoids, which have antioxidant and anti-inflammatory properties. These compounds may help protect the cells that line blood vessels and improve the capacity of arteries to relax and expand, which can lower blood pressure and reduce strain on the heart.
Some studies have found that drinking tea may slightly improve blood pressure, cholesterol levels, and other markers of cardiovascular health. These effects could help explain why people who regularly drink tea have lower rates of strokes, heart attacks and other serious consequences of cardiovascular disease.
There may also be an indirect benefit when people choose unsweetened tea over another beverage, such as juice, soda, or other sugary drinks. Replacing sugary drinks with unsweetened tea reduces the consumption of added sugar, which can help with weight management and metabolic health and thus further reduce the risk of cardiovascular disease.
CNN: Does the type of tea make a difference: black tea or green tea?
Magnifying glass: Black tea and green tea come from the same plant, Camellia sinensis, although differences in how the leaves are processed result in different polyphenol compositions. Previous studies have found benefits associated with both types of tea. In this study, black tea showed more consistent associations with lower cardiovascular risk, although green tea also showed benefits.
I wouldn’t advise someone who enjoys green tea to switch to black tea or vice versa. Both can be part of a heart-healthy diet, especially if people are careful to drink them without added sugar.
CNN: How much tea should people drink? Is there such a thing as drinking too much?
Magnifying glass: Among study participants who drank tea at least once a week, the lowest estimated risk of vascular disease was around six to eight cups per day. The risk began to increase again at very high consumption levels above this figure.
People should not interpret this to mean that everyone should strive to drink six to eight cups of tea a day. In fact, people should be careful when extrapolating this study to their own habits for a variety of reasons, including the fact that the researchers did not use a standardized cup size and their estimates were based on self-reported consumption. The authors themselves specifically cautioned against interpreting this result as a recommended optimal intake.
Another reason to be wary is that tea also contains caffeine. An 8-ounce cup of black tea typically contains about 30 to 50 milligrams of caffeine. Green tea generally contains less, although most forms are not caffeine-free unless the label explicitly states so. The U.S. Food and Drug Administration cites 400 milligrams of caffeine per day as an amount that is generally not associated with dangerous effects. Pregnant people are advised to limit their caffeine intake to 200 milligrams per day and children are advised not to consume caffeinated beverages.
CNN: What advice would you give to people who drink tea regularly or are considering adding it to their diet?
Magnifying glass: For practical reasons, people should avoid drinking tea hot enough to burn their mouth or throat. Repeated consumption of very hot drinks has also been linked to an increased risk of esophageal cancer. Letting the tea cool until it can be comfortably sipped can prevent burning and could help preserve its potential cardiovascular benefits.
People can choose black, green, or other unsweetened teas depending on their preferences and should be mindful of their total daily caffeine intake, especially if they have sleep problems, anxiety, or palpitations.
Those who don’t currently drink tea shouldn’t feel pressured to start. There are many evidence-based ways to reduce the risk of cardiovascular disease, including regular physical activity, avoiding tobacco, maintaining healthy blood pressure and cholesterol levels, and eating a nutritious diet.
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