What Is Black Tea?
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 the fermentation process).
Black Tea and Caffeine
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.)
Black Tea and Antioxidants
Black tea contains a number of antioxidants, which 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.
Black Tea Benefits
Here's a look at the science behind black tea's health effects:
1) Cardiovascular Health
To date, research on black tea's cardiovascular benefits has yielded mixed results. For instance, a 2009 review of nine previously published studies (including a total of nearly 195,000 participants) concluded that drinking three cups of black or green tea daily reduced risk of stroke by 21 percent. However, a 2007 study of 31 adults (ages 55 and older) found that six months of black-tea consumption did not significantly influence any cardiovascular risk factors (such as inflammation and systolic blood pressure). Both the National Center for Complementary and Alternative Medicine and the National Institutes of Health point to this study as evidence that black tea may have no impact on cardiovascular health.
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.
3) Cancer Prevention
While some studies indicate that regular consumption of black tea may reduce cancer risk, others report no cancer-related benefits of black tea intake. Furthermore, some research suggests that black tea consumption may be significantly positively associated with increased risk of overall breast cancer and estrogen-receptor positive/progesterone-receptor positive breast tumors.
Drinking Black Tea for Health
Black tea consumption has not been proven to prevent or treat any health condition. Although black tea intake may offer certain health benefits, it's important to consult your doctor to determine which dose might be appropriate for you. In some individuals, high doses of caffeine may lead to a number of adverse effects (such as anxiety, increased heart rate and blood pressure, and the worsening of ulcer symptoms).
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