Like green tea, black tea is made from the leaves of the Camellia sinensis plant. The leaves are dried and fermented, which gives the tea a darker color and richer flavor than green tea (which does not undergo fermentation).
Here’s a look at the science behind some of black tea’s health effects:
- Black Tea and Cardiovascular Health. In 2001, Boston University found in a study that both short-term as well as long-term drinking of black tea actually reverses something called endothelial vasomotor dysfunction in patients with coronary artery disease. This is a dysfunction which basically serves as a predictor for even more serious coronary events. The conclusions in the study backed up a previously held link between black tea and its propensity to lower cardiovascular problems.
- Black Tea and Diabetes. In a laboratory study published in 2009, scientists discovered that compounds extracted from black tea were more effective at slowing the absorption of blood sugar than those extracted from green tea and oolong tea. Additionally, a 2009 population study of 1,040 elderly adults found that long-term intake of black and/or green tea was associated with lower prevalence of diabetes.
- Black Tea and Antioxidants. Another benefit of drinking black tea is a sizeable one: the abundance of antioxidants in it. Antioxidants are compounds that help the body fight free radicals (chemical by-products known to damage DNA). These antioxidants include quercetin, a substance said to combat inflammation and support healthy immune function. The plant that this tea is made from comes with a plethora of the group of chemical substances known as polyphenol. These substances are another type of antioxidant, which have been found to help in everything from the treatment of brain injury cases to treatments against hearing loss and also, potentially, Parkinson’s disease.
Depending on how strong it’s brewed, black tea contains about 50 mg of caffeine per cup. In comparison, green tea contains 8 to 30 mg per cup, while coffee contains 100 to 350 mg.