Black tea (generic name)
treats Oral leukoplakia/ carcinoma, Osteoporosis prevention, Colorectal cancer, Dental cavity prevention, Asthma, Stress, Diabetes, Metabolic e...
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TraditionWARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Acute pharyngitis, antioxidant, anxiety, cancer multidrug resistance, circulatory/blood flow disorders, cleansing, Crohn's disease, diarrhea, diuretic (increasing urine flow), gum disease, headache, hyperactivity (children), immune enhancement/improving resistance to disease, influenza, joint pain, kidney stone prevention, melanoma, obesity, osteoarthritis, pain, prostate cancer, stomach disorders, toxin/alcohol elimination from the body, trigeminal neuralgia, vomiting.
Adults (18 years and older)
Black tea has not been proven as an effective therapy for any condition and benefits of specific doses are not established. A maximum of eight cups of black tea daily has been suggested. One cup of tea contains approximately 50 milligrams of caffeine, depending on the strength of the tea and the size of the cup.
Children (younger than 18 years)
There is a lack of available information about the safety or effectiveness of black tea in children. Due to the caffeine content, caution is advised.
SafetyDISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.
People with known allergy/hypersensitivity to caffeine or tannin should avoid black tea. Skin rash and hives have been reported with caffeine ingestion.
Side Effects and Warnings
Studies of the side effects of black tea specifically are limited. However, black tea is a source of caffeine for which multiple reactions are reported.
Caffeine is a stimulant of the central nervous system and may cause insomnia in adults, children, and infants (including nursing infants of mothers taking caffeine). Caffeine acts on the kidneys as a diuretic (increasing urine and urine sodium/potassium levels and potentially decreasing blood sodium/potassium levels) and may worsen incontinence. Caffeine-containing beverages may increase the production of stomach acid and may worsen ulcer symptoms. Tannin in tea can cause constipation. Caffeine in certain doses can increase heart rate and blood pressure, although people who consume caffeine regularly do not seem to experience these effects in the long-term.
An increase in blood sugar levels may occur after drinking black tea containing high levels of caffeine. Other early studies suggest that green tea may lower blood sugar levels and increase insulin levels. Caffeine-containing beverages such as black tea should be used cautiously in patients with diabetes. People with severe liver disease should use caffeine cautiously, as levels of caffeine in the blood may build up and last longer. Skin rashes have been associated with caffeine ingestion. In laboratory and animal studies, caffeine has been found to affect blood clotting, although effects in humans are not known. It is unclear whether black tea with or without caffeine would have similar effects. Black tea may stain teeth.
Caffeine toxicity/high doses: High doses of caffeine may cause symptoms of anxiety, delirium, agitation, psychosis, or detrussor instability (unstable bladder). Conception may be delayed in women who consume large amounts of caffeine. Seizure, muscle spasm, life-threatening muscle breakdown (rhabdomyolysis), and life-threatening abnormal heart rhythms have been reported with caffeine overdose. Extremely high doses may be fatal.
Caffeine withdrawal: Chronic use can result in tolerance, psychological dependence, and may be habit-forming. Abrupt discontinuation may result in withdrawal symptoms such as headache, irritation, nervousness, anxiety, tremor, or dizziness. In people with psychiatric disorders such as affective disorder or schizoaffective disorder, caffeine withdrawal may worsen symptoms or cause confusion, disorientation, excitement, restlessness, violent behavior, or mania.
Chronic effects: Several population studies initially suggested a possible association between caffeine use and fibrocystic breast disease, although more recent research has not found this connection. Limited research reports a possible relationship between caffeine use and multiple sclerosis, although evidence is not definitive in this area. Animal study reports that tannin fractions from tea plants may increase the risk of cancer, although it is not clear that the tannin present in black tea has significant carcinogenic effects in humans.
Drinking tannin-containing beverages, such as black tea, may contribute to iron deficiency. In infants, black tea has been associated with impaired iron metabolism and microcytic anemia.
Pregnancy and Breastfeeding
Large amounts of black tea should be used cautiously in pregnant women, as caffeine crosses the placenta and has been associated with spontaneous abortion, intrauterine growth retardation, and low birth weight. Heavy caffeine intake during pregnancy may increase the risk of later developing SIDS (sudden infant death syndrome). Very high doses of caffeine have been associated with birth defects, including limb and palate malformations.
Caffeine is readily transferred into breast milk. Caffeine ingestion by infants can lead to sleep disturbances/insomnia. Infants nursing from mothers consuming high levels of caffeine daily have been reported to experience tremors and heart rhythm abnormalities. Components present in breast milk may reduce infants' ability to metabolize caffeine, resulting in higher than expected caffeine levels. Tea consumption by infants has been associated with anemia, reductions in iron metabolism, and irritability.