What is it?
Black tea is a product made from the Camellia sinesis plant. The aged leaves and stems are used to make medicine. Green tea, which is made from fresh leaves of the same plant, has some different properties.
Black tea is used for improving mental alertness as well as learning, memory and information processing skills. It is also used for treating headache and low blood pressure; preventing heart disease, including “hardening of the arteries” (atherosclerosis) and heart attack; preventing Parkinson's disease; and reducing the risk of stomach and colon cancer, lung cancer, ovarian cancer, and breast cancer. It is also used for type 2 diabetes, stomach disorders, vomiting, diarrhea, and as a diuretic to increase urine flow. Some people use black tea for preventing tooth decay and kidney stones. In combination with various other products, black tea is used for weight loss.
In foods, black tea is consumed as a hot or cold beverage.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for BLACK TEA are as follows:
Likely effective for...
* Mental alertness. Drinking black tea and other caffeinated beverages throughout the day helps to keep people alert, even after extended periods without sleep.
Possibly effective for...
* Preventing dizziness upon standing up (orthostatic hypotension) in older people. Black tea works for this condition because it raises blood pressure.
* Reducing the risk of heart attacks. There is some evidence that people who drink black tea have a lower risk of heart attack. If they do have a heart attack, they are less likely to die if they have been drinking black tea for at least a year.
* Reducing the risk of kidney stones. Women who drink black tea seem to have an 8% lower risk of developing kidney stones.
* Reducing the risk of Parkinson's disease. There is some evidence from large-scale studies that people who drink caffeinated beverages such as coffee, tea, and cola have a decreased risk of Parkinson's disease. For men, the effects seem to be dose-related. For example, men consuming a total of 421-2716 mg of caffeine daily seem to have the greatest reduction in risk. However, there seems to be a significant reduction in risk even with consumption of as little as 124-208 mg caffeine per day. In women, the effects do not seem to be dose- related. Moderate consumption of caffeine (about one to four cups black tea daily) seems to provide the most reduction in risk. Drinking black tea also appears to reduce the occurrence of Parkinson's disease among people who smoke.
* Reducing the risk of ovarian cancer. Women who regularly drink tea, including black tea or green tea, appear to have a significantly lower risk of developing ovarian cancer compared to women who never or seldom drink tea.
* Reducing the risk of hardening of the arteries (atherosclerosis), especially in women.
Possibly ineffective for...
* Reducing the risk of stomach, colon, and rectal cancer.
* Reducing the risk of breast cancer.
Insufficient evidence to rate effectiveness for...
* Brittle bones (osteoporosis). So far there is some evidence that drinking black tea might be linked to stronger bones in women aged 65-76 years. Drinking black tea also seems to be associated with a lower risk of hip fracture in men and women who are older than 50.
* Type 2 diabetes. Some research suggests that Japanese adults who drink a cup or more of black tea daily do not have a lower risk of developing type 2 diabetes compared to those who drink less than a cup daily.
* Lung cancer. There is evidence that men who get more chemicals called phytoestrogens in their diet have up to a 27% lower risk of developing lung cancer than men who do not get these chemicals. Green tea and black tea contain phytoestrogens.
* Stomach disorders.
* High blood pressure.
* Preventing tooth decay.
* Reducing the risk of other cancers.
* Promoting weight loss.
* Other conditions.
More evidence is needed to rate the effectiveness of black tea for these uses.
How does it work?
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Black tea contains 2% to 4% caffeine, which affects thinking and alertness, increases urine output, and may reduce the symptoms of Parkinson's disease. It also contains antioxidants and other substances that might help protect the heart and blood vessels.