- A study of nearly 486,000 people found that regular tea drinkers had an 11% lower risk of vascular disease, a 37% lower risk of ischemic stroke, and a 17% lower risk of heart attack compared to those who didn’t drink tea.
- Drinking six to eight cups of tea a day was associated with the lowest risk of vascular disease among study participants, although experts caution that drinking more tea is not necessarily better.
- Experts recommend drinking unsweetened, non-burning tea and maintaining other heart-healthy habits, including exercising regularly and avoiding tobacco.
A cup of tea in the morning or a pot of tea in the afternoon may be linked to heart health. In a study of nearly 486,000 adults in China over about nine years, regular tea drinkers had an 11 percent lower relative risk of vascular disease than those who didn’t drink tea. The researchers also found that the association varied depending on the type of tea, the strength of the brew, and the heat with which the tea was consumed.
The study, published in the Journal of Internal Medicinerelied on data from China’s Kadoorie Biobank and looked at a range of conditions affecting the heart and blood vessels. Among people who drank tea at least once a week, researchers estimated the risk was lowest around six to eight cups per day. Cup sizes were not standardized, and the study tracked what people were already drinking. He couldn’t determine how much tea a person should drink to reduce their risk.
Why might tea be linked to better heart health?
Tea contains polyphenols, including compounds that act as antioxidants, according to Christopher Yi, MD, a vascular surgeon at MemorialCare Orange Coast Medical Center in Fountain Valley, California. These compounds may help reduce inflammation, improve blood vessel function, and limit oxidative stress, which occurs when unstable molecules called free radicals overwhelm the body’s antioxidant defenses.
Together, the antioxidant and anti-inflammatory compounds in tea may help “protect the inner walls of blood vessels from damage that can lead to plaque buildup,” says James Udelson, MD, chief of cardiology at Tufts Medical Center. Yi suggests that this could be a possible explanation for this association. Other differences in tea drinkers’ diet and lifestyle could also help explain it.
Does it matter how you drink your tea?
In this study, black tea showed more consistent associations with lower vascular disease risk than green tea, and moderately strength tea was associated with lower risk. Udelson notes that other research has also suggested the benefits of green tea. The results regarding black tea and brew strength reflect trends within this group of tea drinkers.
Temperature was another factor. People who reported drinking hot tea had a higher risk of vascular disease.
Separately, a large study of adults in the United Kingdom linked drinking very hot tea or coffee to a higher risk of a type of esophageal cancer. If you just poured a cup, let it cool for a few minutes before sipping.
Udelson recommends drinking unsweetened tea. If your usual routine is a cup or two, Yi sees no reason to aim for six to eight. “This doesn’t necessarily mean that drinking more tea is always better,” he says.
How much caffeine is in six to eight cups of tea?
Tea generally contains less caffeine than coffee, but several cups can still add up, especially if you also save your morning coffee. The amount of caffeine you consume depends on what you make and the size of your cup. For a rough idea, here’s what six to eight 12-ounce servings would contain, based on the FDA’s caffeine numbers. This is just an example serving size, not necessarily what the researchers considered a cup in the study. The amounts also vary depending on the product.
- Green tea: About 37 milligrams per 12-ounce serving, or 222 to 296 milligrams for six to eight servings.
- Black tea: About 71 milligrams per 12-ounce serving, or 426 to 568 milligrams for six to eight servings.
For most adults, the FDA says up to 400 milligrams per day is generally not associated with negative effects, but some people experience the effects at much lower amounts. Don’t forget to count your other sources of caffeine as well. If you feel nervous or have trouble sleeping, your intake may need to be rethought.
Where tea fits into a heart-healthy routine
“There is never a single factor that protects against blood vessel diseases,” says Udelson. “This study clearly shows the additive effect of several behaviors, including tea consumption, not smoking and exercising.”
In the study, the lowest risk was observed in people who regularly drank tea, did not currently smoke and were very physically active. This result reflects the combination of habits.
Yi points to the American Heart Association’s Life’s Essential 8 plan as a broader approach to cardiovascular health. It emphasizes a balanced diet, physical activity, avoiding tobacco, getting enough sleep, and managing weight, cholesterol, blood sugar, and blood pressure. For adults, the association recommends at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous activity per week.
Yi calls the results “encouraging” and says more research is needed to determine how regular tea consumption might affect cardiovascular health. Meanwhile, “for most individuals, regularly drinking unsweetened tea in moderation is a reasonable habit that may provide cardiovascular benefits,” he says.
Reviewed by
Lauren Manaker MS, RDN, LD, CLEC: Lauren is an award-winning dietitian and three-time book author, with over 22 years of experience in the field.
Gn Health
