A comprehensive new study published in the Journal of Internal Medicine indicates that the way people prepare and drink tea may significantly influence their cardiovascular health. Researchers analyzed data from more than 485,000 Chinese adults ranging in age from 30 to 79, tracking participants over an average follow-up period of about nine years. During this time, investigators documented more than 14,800 cases of diseases affecting the heart and blood vessels, including heart attacks, strokes, and peripheral artery disease, which involves the narrowing of arteries supplying blood to the arms and legs.
Participants in the study reported detailed information regarding their tea-drinking habits, such as frequency, preferred variety, brewing strength, and consumption temperature. Examining these habits revealed that individuals who consumed tea at least three days a week experienced a roughly 11% lower risk of developing vascular disease compared to those who drank it less frequently. This statistical adjustment accounted for variables including age, smoking status, physical activity, body weight, and existing medical conditions, though nonsmokers who habitually consumed tea and maintained high physical activity levels demonstrated the lowest overall cardiovascular risk.
Preparation methods also played a notable role in the findings. Moderate-strength tea was associated with a reduced risk of disease, and black tea showed links to lower risks across a broader range of cardiovascular conditions compared to green tea. Both black and green tea originate from the same plant, Camellia sinensis, but differing processing methods yield distinct compositions of polyphenols—naturally occurring compounds containing antioxidants and anti-inflammatory properties. These compounds help protect the cells lining blood vessels and improve arterial elasticity, which can lower blood pressure and reduce strain on the heart.
Temperature proved to be a critical factor, yielding unexpected results. Participants who reported drinking their tea at a burning-hot temperature faced a 16% higher risk of vascular disease compared to those who did not regularly consume tea. Conversely, individuals who drank their tea at room temperature or hot, but not scalding, exhibited significantly lower risk than non-drinkers. Experts emphasize that tea should be allowed to cool until it can be sipped comfortably to avoid burning the mouth or throat, as repeated consumption of very hot beverages has also been linked to an increased risk of esophageal cancer.
Regarding consumption volume, researchers observed that among participants who drank tea at least weekly, the lowest estimated vascular disease risk occurred at approximately six to eight cups per day, with risk beginning to increase again at consumption levels exceeding this threshold. However, health professionals caution that individuals should not interpret this volume as a prescribed optimal intake. The study relied on self-reported consumption data rather than objective measurements, and researchers did not use a standardized cup size.
Furthermore, tea contains caffeine, with a typical 8-ounce cup of black tea containing roughly 30 to 50 milligrams, while green tea generally contains lower amounts unless labeled caffeine-free. The U.S. Food and Drug Administration notes that 400 milligrams of caffeine daily is an amount not usually associated with dangerous effects, though pregnant individuals are advised to limit intake to 200 milligrams per day, and children should avoid caffeinated beverages. Experts note that individuals who do not currently drink tea are not obligated to start, as numerous evidence-based methods exist for reducing cardiovascular disease risk, including regular physical activity, avoiding smoking, maintaining healthy blood pressure and cholesterol levels, and eating a nutritious diet.
